Archive for the jet Category

Flying the Fuel Mule to Seattle

Posted in air travel, airline pilot blog, airliner, airlines, airport, flight crew, jet, passenger, pilot, travel with tags , , , , , , , , , , , on April 9, 2014 by Chris Manno

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Pace yourself: a Seattle turn is 1,600 miles northwest, then 1,600 southeast. Seduced by the 12 day work month, you’re about to find out how 90 flight hours can be logged in so few days. And, for W2 purposes, you’ll pick up another day of voluntary flying, to top out near 100 hours–in only 13 days. Looks good on paper, fly it.

First, consider the illusion: 8.2 hours of flying turns into an 11 hour work day–if all goes as planned. Here’s how it unfolds: report at 11:40 for preflight duties, pushback at 12:40. If, that is, the inbound arrives at the gate on time. Arrival weather can slow that down considerably, and so can maintenance requirements on the $55-million dollar air machine. That could happen before it leaves wherever it started its flight day–Miami, in our case–which will put it on our gate late. Regardless, your day starts on schedule no matter when you eventually pushback.

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Until you get your hands on the jet, consider the route, the weather, and the winds. That last element is crucial, because wind variance from planned can easily add 10-15% to your fuel burn. DFW to Nashville? Barely 2 hours, so plus or minus 10% is nominal. But over 4.5 hours? You can’t ignore the extra fuel burn, which could easily be 1,000 pounds or more. on longer flights, you have to be mulishly stubborn about fuel. Here’s how.

The winds used by the flight planning computer program are fairly accurate, but not perfect. They are a blend of historical data, predictive calculations, and some real time pilot reports. But consider their “Best if Used By” label: they were fresh 3 or 4 hours ago when reported, but with the sun that many hours higher since, you know wind patterns and intensity will change.

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Which brings up another wild card: the front range of the Rockies. You have to cross that ridge northwest bound, probably just west of Pike’s Peak. The old rule of thumb says you’re vulnerable to mountain wave turbulence half again as high as the mountain range, so if you figure between 15,000 and 20,000 on top of a generous average for the range, you’d figure to be a smooth cruise in the upper 30-thousands, right? Seldom works that way and in fact, often the ride is worse higher and better lower. That’s due to many variable factors: the jetstream pattern, heating and temperature bands in layers, and the orographic effect of the uneven range peaks themselves. Plus, the higher sun angle throws adiabatic heating into the mix, adding convection to the orographic disruption. End results: riding a dump truck down a dirt road.

Add those concerns to your awareness of the slimmer margin between high and low speed buffet at the higher altitudes, particularly early in cruise when fuel quantity and thus aircraft weight is the highest. Sometimes, lower than optimum cruise altitude is a wiser choice if there’s a possibility of significant turbulence. Again, there will be a higher fuel burn for that segment of cruise.

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So there’s another possible fuel penalty, and it’s not as simple as the increased incremental fuel burn at a lower altitude for the front range transit time, although that is substantial. You also have to add the fuel burn for another climb back to optimum cruise altitude for the remainder of the flight.

Plus, if anywhere in the 1,600 mile route we discovery that a lower altitude is a better ride compared to a turbulent optimum cruise altitude, we’re going to descend and accept a higher fuel burn. Again, short flight like Nashville? No worries–just stay low. But not for 2-3 hours as in the Seattle flight.

So, in your head, you’re computing a comfortable arrival fuel, plus an extra 15% for wind and turbulence options. And “comfortable” depends on current and forecast Seattle weather. Yes, “current” weather in Seattle is important for a couple reasons. First, if their weather is causing flight delays there now, there’s a good chance for the imposition of arrival metering–unless it clears in the 5 hours before your planned landing time. That could mean an outbound (YOU) ground stop, or even enroute metering, vectoring or slowdown–all of which cost fuel.

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The ground stop eventuality saves jet fuel, but burns YOUR energy, adding an hour or more to what’s typically an 11-12 hour workday for a Seattle turn. That type of delay on top of any maintenance or inbound delay can make your day an endurance contest: just getting to Seattle in 5-ish hours is only half of the game–you still have to juggle all of those factors and the same mileage southbound.

There are a few windfalls that will likely come your way, too. Frequently, the cargo load will drop off, sometimes the passenger count too, but that’s very unlikely for Seattle. But the cargo weight dropping a thousand pounds or more will allow an early climb to a higher cruise altitude with a lower fuel flow and more favorable winds.

Today we’re actually flying longer route on a more northerly course, passing east of Denver, and I can see why: there the jetstream becomes more of a crosswind than the headwind we’d get on a more westerly route. The typical westerly route is shorter mileage on a map, but not in the sky where the flow of the air mass acts like a treadmill: it’s already moving against us, whereas on the more easterly course, it’s not. No treadmill effect, or at least significantly lower.

So, here’s the numbers game for today: SEATAC’s landing south (grumble: longer arrival and  approach) with variable winds (could switch to north, you hope) and neither poor weather nor delays. Ceiling 700 to 1,000 and, with the trend data, improving. Good. 6.0 arrival fuel will be fine, and it will likely balloon to 7 if all goes well but comprises a good pad if not. Worst case, we visit McChord AFB twenty-some miles south.

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Weather at DFW makes for outbound delays, not due to the heavy rain so much as the convective (read: spring thunderstorms) cells dotting the radar, disrupting the standard departure routing and forcing all jets into a 10 mile in-trail spacing to allow radar vectoring after takeoff. More grumbling: sure don’t want our southbound leg to be delayed or god forbid, ground-stopped in Seattle. But the steadily moving frontal line snarling DFW will be well clear by the time we return around 10 pm. We’ll worry about that later.

Somewhere over Wyoming at take-off plus two hours, you share a wry observation with the First Officer: “We’re not even halfway yet.” She laughs: “And even that’s only halfway to halfway.”

Hello, Idaho.

Hello, Idaho.

True enough. Because every single step of analysis, planning, preflight and execution repeats itself sure as Bill Murray’s Groundhog’s Day as soon as you set the brakes in Seattle.

Pace yourself: it’s going to be a long day. If you’re lucky, you’ll get home 12-13 hours after you left for the airport this morning, allowing you to get a good rest in order to do it all over again tomorrow.

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Fried Sky with a Side of Regret.

Posted in air travel, airline, airline industry, airline pilot, airline pilot blog, airliner, flight, flight attendant, flight crew, jet with tags , , , , , , , , , , on March 29, 2014 by Chris Manno

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Night falls slowly, painfully on the flight deck westbound. Chasing the sun but losing, sunset grudgingly unfolds in slo-mo, Pat Summerall running color commentary: “Oh my, that’s not how it’s supposed to happen.” A burning lip flecked with cobalt, shafts of charcoal stolen from the blue promising a stormy beating for a landscape miles away, yet you know, feel, what you can’t see. Darkness comes in withering shades and declining latitudes, searing the horizon, azure overtaking the florid arc as if the smoldering, sighing sun just didn’t give a damn anymore.

Entropy flies in the cargo belly: chickens–baby chicks breathing through air holes in cardboard cartons, never imagining themselves winging 500 knots across the ground–and radioactive material (aft compartment), tagged bags and other stuff, plus a tissue sample on dry ice rushing to doctors on the sunset coast, deciding if someone in the eastern darkness can live or die, or so the cargo folks told me.

Not really more sanguine upstairs in the pressure hull defying the -60 degree stratopause inches away, with a meager partial pressure of oxygen that would instantly start the blood bubbling and the gas escaping crushed lungs in a fog. Never mind, eyes on the prize, 250 degrees true, beyond the jagged threshold of the Rockies and Sierras. Less than an hour to go.

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While I’m ten stories forward of the aft jumpseat confessional, I’m aware of what’s unfolding nonetheless. One just left her husband, the other just got left. Forward galley, well he’s an old friend, a gay guy with a good head on his shoulders and compassion enough to care how hard relationships, same sex or otherwise, can be when the wreckage piles up.

And we both have Old Testament faith in flightcrew clannishness: we’ll get through whatever together, day, night, a few thousand miles or continent, even an ocean away; the jumpseat and crew van and the gawd awful bidsheet that binds us hot forges a flightcrew stronger than we could ever be alone. So we never really are–and the two pros will smile and work that coach cart, they’ll do the giving that they always do, with stronger hearts regardless of the weight they’re bearing.

Me, up front, I’m just the timekeeper, shoveling coal to stoke the boiler fire and constantly questioning the course I’ve set: can we get the chickens and tissue and broken hearts and shattered dreams to the far coast with fuel burn I counted on? Does the X-Ray vision of the radar and the wind plot say that the wedding gown carefully, almost religiously stowed in the forward closet will make it timelessly to the reunion with the soul-sister maid of honor waiting to pick up the bride in the City by the Bay?

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Flex. Breathe, flex again; crank the rudder pedals back, unfold the six foot scrunch another inch, strapped in just the same. Breathe. Force the HEFOE litany carved in stone an age ago: “hydraulics, electric, fuel, engines, oxygen,” amen. Simple, my part as captain is: keep us flying forward, rightfully, safely. Be the faceless guy in the locomotive cab of the wailing freight train, dragging an ice trail across the night sky, contrails silhouetted in moonlight like silver rails against a shadowy landscape thundering below: dusk left and right, darkness behind–we sail on ahead nonetheless.

Crossing the last waypoint before arrival and descent, claim that inward smile: job done, promises kept; plans worked, fuel plenty, brides, chicks and heartbreak alike–delivered. From here it’s only about negotiating the descent, the approach, landing and taxi in. Cake. And folks will either be happy or not, but you did what you promised them. Chicks will either recognize a new coast or they won’t, someone in New Jersey will get good news (I hope) or bad, and somebody’s big day will lead to a lifetime of heartache or not. And the heartbreak cabin crew will be replaced by another eastbound, instantly bound by the Gilligan’s Island of flight crews: castaways, for better or worse, on a thin air island eight miles above and a world away.

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Yet in the end, it’s not regret, really, that darkens your sky, but in a way it is: can’t be sure how any of what we landed just now turns out afterward, though I’m not sure I’m supposed to know. Back off; take a deep breath and set out once again on the ironclad litany for the eastbound flight, the homeward leg. Regret can wait; another worthy ark of eastbound hope and dreams and everything in between sails on at brake release and pushback in an hour. Claim a breath, a moment of peace, then get your head back in the game: details, captain, and promises you must keep for the hundred some souls on board.

Keep ‘em, every one, defy the sunrise alone. Careful, truthful, the sky is the footpath home.

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Malaysian 370 and the Land of Oz.

Posted in airline pilot blog, airport, airport security, jet, passenger, pilot with tags , , , , , , , , , , on March 19, 2014 by Chris Manno

Since we first considered here what didn’t happen to Malaysian Flight 370, there’s been a virtual flood of “theories” proposing what did.

The problem is, all of them start out with “it’s possible that” (rather than “the facts indicate”), from which a thinking person could only conclude what “might” have happened–with no better chance of knowing what actually did. Worse, once the boundaries are stretched to include “possible” and “might” as operative terms, you no longer have an investigation at all; rather, you have a piece of creative writing.

So much of what has been advanced as “theory” lately falls into that category, and those who are not airline flight operations insiders are most vulnerable to what is no doubt their good faith desire to find answers. But, with neither the technical background nor the aviation experience to separate what’s plausible from what isn’t, the results obscure the very truth they search for in the first place.

Malaysian authorities brief the press.

Let’s start with the most recent red herring “released” by Malaysian authorities–“the big left turn,” which supposedly “proves” that the turn was deliberately programmed into the flight computers, presumably by someone with nefarious intent.

In a word, that’s meaningless. There are just too many active and passive ways for “the big left turn” to be executed, even with no “programming” by what they insinuate was a rogue pilot. For example, look at the photo below:

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The letters to the left are all navigation waypoints, composed of four or five character words representing geographic navigational fixes. Notice the waypoint “PROUD,” followed by the word “then,” which is atop the five empty boxes?

Below that, see the words, “Route Discontinuity?” That is the aircraft’s Flight Management System (FMS) telling me, the pilot, that I haven’t told it where to proceed after PROUD. In other words, there’s a break in the route and if I don’t fill those five empty boxes, the FMS will execute a big left turn (or right, depending on the shortest distance due to winds) and backtrack along the route to the points it came from.

And that’s just one possible, passive real time cause for “The Big Left Turn” so many theorists–including the Malaysian authorities and a news-starved press corps rushing to fill dead air–inexplicably point to as proof of some sort of deliberate, diabolical course programming.

Also, for some unfounded reason, the Malaysian authorities insist that “such a drastic turn could only be done by the autopilot coupled to the Flight Management System.”

Power control is key to airspeed.

Absolute nonsense. Daily, flight by flight I and hundreds of airline pilots hand fly all manner of climbs, descents and turns at all altitudes and speeds. That’s what we do.

Which brings me to the newest red herring that has the press panting and Malaysian authorities puffing up: the captain’s flight simulator video game. Supposedly, they’re going to search the game’s memory to see if the captain had “planned or practiced programming or flying” the Dreaded Big Left Turn.

Seriously? A captain with 18,000 flight hours needs to “practice” a left turn, or rehearse the FMS direct track to a waypoint? Which leads from the ridiculous to the absurd: no career pilot would need or want to “rehearse” a task that is on the level of an average person turning left into their own driveway. Even worse, accepting that the Malaysian authorities are investigating this as a serious clue is to accept that such a fundamentally meaningless red herring even bears investigation.

Once you do, it’s down the rabbit hole: “might” and “could” substitute for “did,” “assumptions” displace facts, which leads to conclusions that hold water like a sieve. Meanwhile, as the Malaysian authorities proffer useless leads, contradicting themselves with their own red herrings, inconsistencies and half truths–while the real investigative trail goes cold, and gets old.

What would motivate Malaysian authorities to divert public scrutiny to such empty yet showy “revelations?” Could it be to deflect attention from their top to bottom mishandling of the incident since the first minute: if, as the Malaysian authorities finally admitted, their military radar detected an unplanned, unauthorized penetration of their airspace by an uncommunicative jet at 35,000, why did the Malaysian Air Force not scramble fighters to intercept this very clear violation of their airspace and threat to their population at large?

Malaysian Air Force F-18

If they had (yes, their Air Force has fighters and they are guided by the very radar that detected the straying airliner) no one today would be searching for Malaysian 370–because they would have followed it and determined their course and intentions.

It would seem less embarrassing for government and aviation authorities to paper over that glaring failure with sideshows like a crewmember’s flight simulator, or which pilot spoke last on the radio, or a mysterious Big Left Turn–which is probably why they’re doing exactly that.

And into the dead silence left by a complete lack of real evidence, come the voices of those who propose creative theories whose flames are fanned by social media with the nonsensical equivocation, “well, nothing else makes any more sense,” or “you can’t prove this didn’t happen.”

For example, some pundits propose there “might” have been a “fire,” which “could possibly” explain the transponder being “off.” Not “turned off,” in this scenario seemingly validated mostly by the way Hollywood portrays cockpit electrical failures: sparks, lights flicker out like in your house during a thunderstorm, then someone barks at a radio, “Ground control, come in please! Omigod–it’s dead!”

But a Boeing jet is not like your house, nor a Hollywood make-believe cockpit. There are multiple power sources and current routings, all designed to swap sources and even types of power to vital equipment–especially to communications and safety gear, including radios and firefighting systems.

And even if there were a fire, a turn toward land and an immediate descent with a mayday call is as instinctive to pilots as breathing and, in my Boeing jet–just like theirs–under most conditions I can set it up to perform the descent and level off safely even without me maintaining consciousness. That’s the way airliners are designed to fly, that’s the way professional pilots fly them.

And as my colleague Jeremy Giguere (he pilots The Big Kahuna, the Boeing-747) notes, Swissair 155 had a fire that destroyed the aircraft–but they talked with controllers for a full 15 minutes as they headed for land.

Fire? Sinister flight path reprogramming? All come under the venerable pilot term “WAG,” which translates to “Wild Ass Guess,” which is exactly what it sounds like.

So let me be clear: I don’t know what happened to Flight 370–and nor does anyone else. That’s because there are no facts from which to draw conclusions and until there are, I won’t attempt to wring fact from fiction.

To do so is to enter the Land of Oz where trees throw apples and winged monkeys dart about the sky, and Dreaded Big Left Turns plus Fire “possibilities” create a chaos that obscures what really ought to be a quiet, diligent search for facts and truth, when or if ever they are discovered.

Despite the shameful Malaysian bungling and the pointless social media circus following this puzzling tragedy, I believe in time the real facts will come out. Then a properly conducted investigation will yield a probable cause that will allow the aviation industry and flying community to make air travel safer.

The 200 lost souls and the loved ones they left behind deserve nothing less.

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Malaysia Flight 370: What Didn’t Happen.

Posted in airline, airline industry, airline pilot blog, cruise ship, fear of flying, flight crew, jet, Malaysian Air 370, security with tags , , on March 15, 2014 by Chris Manno


Speculation on what happened to Malaysia 370 now runs rampant across the world media, just as it always does after any airline disaster. But as usual, most of what the “informed sources” hypothesize is unfounded or at least, not based on fact. That’s because whether the “experts” popping up on broadcast media want to admit it or not, there are few facts; and for all the wrong reasons in this case, there are fewer than ever.

That in itself is significant and, in my judgment from the perspective of one who makes a living piloting Boeing jets, a major factor largely ignored in the media. Specifically, what didn’t happen to that Boeing 777 holds the key to what did.

First, let’s start with the most obvious clue, which basically is the common denominator in one major risk factor that affected everyone who boarded Malaysia flight 370: the two travelers with stolen passports. No, I’m not even suggesting that they were players in a terrorist plot, although that is possible. Rather, the common denominator risk factor is this: clearly, third world security once again and not surprisingly, failed.

The Interpol database listing those stolen passports would have been cross checked in the United States, Canada, Great Britain, and every country in Europe. Was the database available to Malaysia? To the airport in Kuala Lumpur? Of course it was–but the database was never crosschecked against the flight manifest. That’s the starting point of what didn’t happen, and that trail only gets worse.

Is there a good reason why the Interpol list wasn’t checked? Actually, the more important question, the answer to which bears heavily on the common denominator in play, is this: does any good reason for not checking even exist? Technological deficit? Budget constraint? Manpower? Mismanagement? Incompetence? Is there a “good” reason for this failure, which would imply there is a level of acceptance appropriate for the failure to secure the screening process?

If what the rest of the modern world considers essential–airline and airport security–is simply not maintained in Malaysia, what else is not done there?

“We don’t really know.” Seriously?

That brings me to the jet itself. I’ve had a printer message pop up at 40,000 feet that read, “Please check the vibration level on the right engine–it’s reading high down here.” Down here, in this case, is my airline’s technical operations center that is receiving, monitoring and screening the extensive data stream flowing from my Boeing 737-800, including detailed telemetry from the two CFM-56 high-bypass jet engines.

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Malaysia Air says there was no data stream from flight 370, while Rolls Royce, the manufacturer of the engines on that 777 who monitors that data stream says there was. Which raises the larger question of why the two disagree? Why would the airline–and the authorities governing airlines in Malaysia–not have the data, or say that they didn’t? Again, is there even a good reason? Lost data? Technical shortcoming? Incompetence? Insufficient budget or manpower resources?

Which brings worse to worst: untruth. In an incident I witnessed from the left seat, the key piece of cause data that nearly led to hull loss with 150 fatalities (including me) was the radar plot and audio tape of the Mexico City Approach Control’s vectoring. Which, of course, went “missing” in the subsequent investigation.

Which lowers us to the worst of the worst factors at play in Malaysia and Mexico and other third world countries where, as Asiana Airlines proved last summer, a “competent and qualified” cockpit crew could fly a perfectly good 777 into a sea wall. That is, culture.

Asiana crew flies into seawall on landing..

Certainly, the Ethiopia Airlines copilot who recently commandeered his own 767 and nearly ran it out of fuel over Central Europe was, according to Ethiopia Air and their aeronautics regulators, “highly qualified” like the Asiana crew.

“Hijacked”–by the copilot.

In a country like Malaysia where no heads roll when passports are not checked against databases of security risks, stolen documents, and worldwide watch lists, when key flight data may or may not be recorded, monitored or maintained (all that data, by the way, is key to modern jet safety and maintenance), when convention and tradition–essentially culture–mandates that power relationships (and likely, money) transcend the first world strictures of duty, common sense and personal responsibility–what does anyone think could–and did, and will–happen?

The only reason this list of failures–which barely scratches the surfaces of things that didn’t happen, causing the disaster that did–is a surprise to the flying public is because of a twofold consumer bias: price, and marketing. A 777 in the paint job of Malaysia Air looks as impressive as a 777 in United Airlines paint, and they both have a $250 million dollar price tag. But that’s where the similarity ends–technical capability, maintenance standards, government regulatory oversight, budget, manpower and culture run the gamut–and there is a bottom end upon which the airline passenger who goes by appearances gambles everything.

Consider the billion dollar cruise industry, where it’s common to register a half-billion dollar ocean liner in the country with the least competent (read: least costly/interfering) regulatory capability, like Liberia, the Bahamas, or Panama. And when a mega-ship’s engines fail in cruise, or the steering quits, or a fire disables the electrical system, or the incompetent captain runs the ship aground showing off, we get a thousand personal anecdotes, cell phone pics, YouTube videos and talk show interviews from those who survived the incompetence, decrying what didn’t happen that should have prevented what atrocity actually did.

“Experienced,” certified Costa cruise ship captain Francesco Schettino runs ship aground–then abandons the ship and 2,000 passengers.

How does that regulatory, cultural and operating failure play out at 35,000 feet and 500mph? Ask the passengers of Malaysia 370 about the end result–if you can find them. Because in their case, all of the above things that should have protected them did not.

The bigger mystery in the Malaysia 370 disappearance isn’t what happened, or even what failed to happen which caused the loss of 200+ lives. Rather, it’s that people are actually surprised that it did.

. . . a week later: still nothing.

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A “simple” aircraft change? You tell me.

Posted in air travel, airline delays, airline pilot blog, airliner, airlines, airport, flight crew, jet, passenger, pilot, travel with tags , , , , , , , on December 1, 2013 by Chris Manno

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Walking down the jet bridge to the plane, flight plan in hand after outwitting two balky printers, and I overhear a man telling a woman, “It was something to do with the plane coming in.”

Maybe a touch of skepticism, or maybe I’m over-thinking because I’m a little defensive since I’m the one who flew it in. Late.

“This flight’s late because of something with a plane in Dallas?” she asks.

And also, I’ve already taken a load of crap from the Number 4 flight attendant, urging me to take whatever shortcuts I can to speed up this turn-around so she won’t miss her 2-day New Orleans trip, which she really wants to do.

I want to un-hear that: I don’t take any shortcuts, ever, and it’s difficult for me too–I have a life, and a body clock that doesn’t care for flying after midnight. But that’s the captain double-down: tired, late–you don’t rush, you take extra care to not mess something up.

“The jet we were supposed to fly out of DFW took a few birds in an engine on their approach,” I interrupt, breaking my own cardinal rule of maintaining invisibility, “So we had to swap planes.”

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“Oh,” she says, still not sounding convinced. I can’t really blame her for that, because it does seem like a pretty simple thing, a swap, right?

You tell me.

Flashback: I meet the inbound crew as they deplane. This is where captains exchange a look that usually tells the story. Normally, at that moment, the captain handing over the aircraft says something preemptive like, “Good jet.”

This time, silence. Then the “other” look. “We hit a bunch of birds on the approach.”

Crap.

“Where?” I ask.

“Mostly the nose.” Mostly. I know what that means. I have to ask.

“Any adverse engine indications?”

He shrugs. “Not that we noticed.” Good–maybe it’s just a guts clean-off and a thorough exterior inspection.

But I know better. “Well,” I say, making a lame attempt at levity, “that’s what they get for indiscriminate flocking.”

He laughs weakly, giving me a “you’re screwed” look as he walks off. Guess I’ll save the “canary-al disease” joke for another bird strike.

I drag my flight gear down the jet bridge and park it near the door to the ramp. Down the stairs to the ramp, then over to the nose gear.

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Yup–bloody skid marks, guts on the strut. But not a real problem. Two maintenance techs are already on the ramp, flashlights in hand, meaning they’d just done a close-up inspection of an engine. One is shaking his head. Crap.

He jerks his thumb toward the right engine. “It took a few,” he says.

CFM 56 N1

I check for myself: shiny spots on the huge N1 fan blades, meaning they’d been “shined” by a semi-soft impact at 30,000 RPM and 160 mph. Some down-ish debris in the first and second stages, and the final clue, the exhaust area smells like burned kerosene and rotisserie chicken. Actually, the latter makes me a little hungry.

“Well,” I ask, “what do you think?”

One tech shakes his head. “They’re probably going to have us bore-scope the engine. But even if we don’t, it’ll take at least an hour or more to get inside to make sure there’s no debris blocking the oil cooler.”

Or any of the other gazillion probes and moving parts. The engine can eat birds no problem, but it’s the fine tolerances for moving parts and intakes that demands close inspection: even dust-fine volcanic ash can trash a jet engine.

My internal clock calculator runs: it’ll take a few minutes for the techs to report their findings to Maintenance Control in Tulsa. Give them fifteen more minutes to come up with a plan: clean? Clean and bore scope? If the former, expect a 1:30 delay; the latter means taking the aircraft out of service.

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I could be fine with the first option if the two mechanics are (any of them who haven’t been laid off are super-experienced) but if I were Tulsa I’d insist on the second–and I’m sure they will.

So I’ll shortstop this by calling Flight Dispatch.

“We haven’t been notified of an engine problem yet,” he says, sitting in the War Room two miles south of the airport. “But I’ll  go talk to the equipment desk to give them a heads-up.”

They’re the folks–also in the war room–who reassign jets to meet needs such as this. The ramp crew is milling around with questioning looks: do we load bags and cargo, only to have to unload and reload them on another? That takes time.

The techs shrug. “We have to call Tulsa.” They head for the jet bridge phone.

“Just hold off,” I tell the Crew Chief, rolling the dice. If I’m right, this will speed the process of switching planes. If I’m wrong, we’ll be late and it’ll be my fault. But I’m betting that once Tulsa works their decision tree and passes it along to the Equipment Desk, we’ll be getting assigned to a new “tail number.”

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Back up to the gate podium where my crew is milling around, trying not to act like they’re dreading their 10 hour workday going to twelve or more. I am too.

“I’m betting on a change of aircraft,” I tell them. “I’ll let you know.”

“Can you call catering?” our Number One asks. “I don’t want to have to do a First Class meal service with the leftovers from some other catering.”

“Sure,” I answer. We can take whatever extra fuel there is on board, though I make a note to subtract the max landing weight and fuel burn first, but she wants to do a decent service.

I type the code for our flight into the computer and instead of departure time, it says “DCN 13:40.” Good–that means Tulsa has put a maintenance hold on the flight, saying they’ll have a “decision” by 13:40. We’re supposed to push at 14:05, so we know this one’s going “off-schedule,” but at least the Equipment Desk can line up a spare.

We’re at pushback time. I call Dispatch back. “Any word yet?”

“No,” he says, “but call me back in ten minutes and maybe they’ll have something for us. But I do know they’ve burned all the 737 spares today.” Meaning there have already been several maintenance swaps today. Some days are like that, and it has more to do with the birds’ bad planning than the airline’s.

Some of the more than 40 jets damaged by hail in the storm, awaiting inspection and repair.

That elicits a line of people asking if they can be put on another flight. I say nothing, but would warn them that they’ll end up standby on a later flight–better stick with this one. Glad I’m not an agent, because people are demanding to know what we don’t know ourselves: decisions are unfolding, not some hidden secret.

My cell phone rings: Flight Dispatch. “Looks like the Equipment Desk is stealing the 6 o’clock’s bird. It flew in from LaGuardia.” That means a later flight will be delayed outbound. But likely, that’ll be a flight terminating at its destination, not bringing back 150 people (for a total of 300 waiting on this one, counting both legs) as we are. “It’s two gates down.”

It’s not official yet, and I don’t want to start a stampede. But I can get down there and determine what we need on board, plus get the F/O busy preflighting the aircraft. “Looks like gate A-17,” I tell the Number One quietly. I remember the call to Catering, but they can’t start swapping until the word filters down.

gate area 1

The pilot’s signature date in the new aircraft’s logbook is yesterday–Dispatch says it flew in from LGA. Did the captain forget to sign it? Or has it not flown yet today? If the latter, that means a longer origination preflight rather than just a quick through-flight checklist.

“Just do the full origination,” I tell the F/O, who’s already grouchy, but too bad. Better safe than sorry. “I’ll do the outside,” I tell him, throwing him a bone. I actually like the outside–I like the jet, it’s beautiful: high wing, graceful 7′ winglets. The smell of jet fuel–and I’m still thinking wistfully of rotisserie chicken.

Two gates down, I see the catering truck pull up to our old jet. Good–that means that if the catering company has gotten the word, the assignment is official so now I can get a new flight plan (they are aircraft specific) and flight release from the computer on board and the paperwork from the gate printer. Time to wrap up the exterior admiration and get the release done upstairs.

catering1

As I fold up the new flight plan, up stairs in the terminal, a young woman, a passenger, approaches me haltingly.

“Can I ask you a question?”

“You just did,” I answer, then kick myself: a nervous flyer, stupid. You’re such a smart ass.

She brushes it aside. “Is it dangerous when birds go into an engine?”

“No,” I answer honestly. “Not unless they’re really huge. The inbound crew didn’t even notice any engine effects.” I consider telling her about the homey baked chicken smell wafting from the tailpipe, but I shut up.

 

I fold my stack of flight paperwork and head for the cockpit as boarding starts. The door warning panel shows both cargo doors open, which means they’re at least loading stuff–I can hear the tumult of bags and cargo from the forward hold–and the aft catering door is open, so at least that swap is underway, too.

lights doors

We finish our preflight, verify the route and refile an ATC clearance twice before the ATC computer accepts us, having timed out the original clearance.

The F/O is grumpy again because I overruled the high Mach number he wanted to use at cruise. But that makes little sense: we’re pushing back an hour and twenty late; the higher Mach number might shave 5 minutes off, but for a thousand pounds of fuel? Really? I’m all about arrival fuel, which means time and options.

“You ready for me to close up?” the agent asks, poking his head into the cockpit.

“Not yet.” I have one eye on the fuel totalizer–they’re still pumping fuel aboard, and that requires at least one escape path for passengers in case of fire. And it’s pumping slowly.

fueling 1

Finally, the total reads 19,400 pounds. “Go ahead, pull the bridge,” I say.

With the jet bridge gone, the ground crew begins our pushback. Going to be late into the west coast, even later back here. After midnight, driving home.

Worry about that later–there are over two thousand miles and an equal number of details to be managed to exacting standards between now and then.

Back to the present.

“Why does a simple airplane change take so long?” the woman on the jetbridge repeats.

I’m back to my cloak of invisibility, heading for the cockpit. You explain it to her, I tell her travel companion, in my head. I still have one more set of everything to accomplish before we all get to drive home.

sunset crz

The Flight of the Pilgrims

Posted in air travel, airline pilot blog, airliner, airlines, airport, flight crew, jet, passenger, pilot, travel with tags , , , , , , , , , , , , , , on November 23, 2013 by Chris Manno

The construction paper Indian headband was festooned with crayon-decorated paper feathers, hand-colored in orange and brown. The boy under it had the whirlwind dishevelment of preschoolers, with boundless energy and activity pulling clothing awry, and he stood staring wide-eyed at the airport equivalent of a Disney character–the airline pilot.

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His beleaguered mom, holding a baby on one hip while attempting to fold up a stroller, says, “He’s the one who will fly the airplane for us!”

“Police man!” The boy chirps. You laugh at that. The pilgrims–literally, in the pint-sized dynamo wearing crayon feathers–are flying: it’s the holiday season.

“I can help with either the baby or the stroller,” I say, realizing that I’m not even halfway qualified to operate the Byzantine affair of joints and latches that fold-up strollers have become. But I’ve also spent a whole flight day with baby puke or worse drying on my uniform, so I’m more willing to take on the stroller.

We'll remind you of the proper procedure after you've successfully accomplished it.

The average business traveler, typically posing as studiously bored and self-assured, couldn’t hold a candle to pilgrim mom, juggling kids, strollers, car seats and bags.

And that’s because unlike the straphanger biz flyer, the pilgrims are not simply going from point to point, conceding their presence to the process of travel–flight, in our case–grudgingly, and with neither wonder nor trepidation.

But in the kid’s eyes, wide and clear, there was the wonder of Thanksgiving, turkeys, family; who even knows what flight actually is, but it’s bound to be magic!

“Can I give you this?” I say, digging into my suitcase. I’ve been dragging this bulky thing around for weeks, figuring when the families start their holiday migration, I could give it to someone who could use it.

“It’s a car seat cover,” I say. “you don’t want her” I point to the little one still on her hip, smiling almost slyly, “car seat getting grimy in the cargo hold.”

DFW C-2

And the cover has taken up most of the spare space in my bag. Darling Bride was going to throw it out, because our “baby” is now a teenager. I said no–not just to the throwing out, but also to my membership in the parent club concerned with such things. Cute baby, too. She deserves a clean car seat.

“Are you serious?” mom asks, looking over the bag almost perfectly sized for the car seat among her pile of hand carried bags.

Well, yeah I am serious. I actually need to get down the jet bridge myself, and get on with preflight, fuel loads, landing weight, takeoff thrust (we’ll use MAX and don’t forget the wet runway correction), weather enroute, systems downgrades and setting the jet up for flight.

But first, I can share a pilgrim moment myself.

“Well only if you want,” I say. “We always used this, and it even makes it easy to carry and retrieve from baggage claim.” I miss those days, our years of travel with our little one, a sweet girl like the one in her arms. Now she’s a teenager, 5′ 8″ and of course still wonderful as ever, but dads still get wistful sometimes about good old times.

“Sure,” she says. “Thanks!” I stash her car seat in the bag, zipping it deftly, though not as smoothly as her stroller disassembly but still. I attach the bag tag the agent hands me.

“You’re good to go,” I say, glad that my bag’s finally unstuffed. “Tell the pilgrims at your Thanksgiving dinner I said hello,” I tell the pre-schooler in the construction paper head dress. He still just stares, and I only wish I knew what he was thinking.

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But best to get on board before the spell wears off, before he dashes off in perpetual motion, in flight, imaginary or real.

I’ll take care of the real part, I decide, walking down the empty jet bridge to the cockpit. We’ll take him, his family, the elderly folks in wheel chairs cued up at the gate for pre-boarding, the college students with their books and backpacks, military men and women; everyone–we’ll do more than just fly.

It’s a holiday pilgrimage to family and home, tradition, reunion, togetherness. More than just a flight, we’ll make a passage together.

Okay, as soon as they all deplane safely into the arms of family and friends, I’ll turn right around and retrace the flight path with more pilgrims, connecting them with the places and things that matter to them.

Crowded terminals, packed flights, cranky kids, beleaguered moms, family, holiday and finally home. That’s the flight of the pilgrims, an annual rite that often ain’t pretty, but always has it’s windfalls. Like my little headdress friend, and our mutual admiration for the costumes we each wore.

From now until sometime after New Years, air travel becomes more than just flight. Since I fly year round, I was going to be here anyway, but somehow there’s just more to it right now. Maybe it just seems more meaningful at either end, and maybe it really is. Could be sharing space with believers in pilgrims, or the mirrored reflections of such things in our own lives playing out anew in those making their way across the country this season.

Something to think about at level off. For now, time to get ready for flight.

DFW ramp dusk

Jet Fuelishness

Posted in air travel, airline pilot blog, airliner, airlines, airport, flight crew, jet, passenger, pilot, travel with tags , , , , , , , , , , , , , , on November 15, 2013 by Chris Manno

I’ve always agreed with the pilot maxim, “The only time you can have too much fuel is when you’re on fire.” But, as with all things in life, there’s a catch: first, you have to be able to lift the weight into the air, and second, you have to be able to bring the tonnage to a stop on landing.

fueling 3

Two simple requirements, or so it would seem–yet nothing could be further from the truth. Let’s look at the second requirement: stopping distance.

All month I’ve been flying into John Wayne-Orange County Airport in Santa Ana. That’s by choice–I like the  typically favorable weather, plus the lack of ground traffic that makes for a quick in and out. Plus, the food options from Gerry’s Wood Fired Dogs to Ruby’s awesome turkey burgers rival the Udon, Cat Cora and Tyler Florence options at San Francisco International. But I digress.

sna 10-9

Today I’m flying the 737-800 from DFW to Santa Ana (SNA) and approximately 2 hours from takeoff, I’ll call Flight Dispatch and ask, “What fuel load are you planning today?” And he will say, “I don’t know.”

That’s because the flight planning system won’t issue a fuel load until one hour prior. I realize that–but as crew, we show up one hour prior and by then, the fuel is already being pumped into the jet. I want to shortstop a problem unique to SNA. That is, fuel is really expensive at some California airports, including taxes, airport assessments and surcharges. So it does make sense to “ferry” some fuel into those airports.

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That is, if I need an arrival fuel of say, typically, 5,200 pounds in order to have divert or go-around options at the destination, we fuel up to that total, then add “ferry fuel,” or an additional upload so as to require less refueling, buying less with the added fees, taxes and cost for the return flight.

Problem is, SNA has a fairly short runway (5,700 feet, versus 13,000 at DFW) making stopping distance is critical.

So, while extra fuel saves money on refueling (yes, you have to figure that it does exact a higher fuel burn inbound because of the additional weight), we still have to have a sufficient stopping margin.

737 landing crop

In all cases, the maximum landing weight of the jet based on the structural limit is 144,000 pounds which, on a dry runway, requires 5,300 feet out of the 5,700 feet available to stop. I discount headwinds, which are favorable, and simply disallow tailwind corrections: at 144,000 pounds, I require zero–I’m not even trifling with a 400 foot margin touching down at 150 knots.

So my effort in calling Dispatch is to intervene in the numbers game: do NOT plan max “savings” ferry fuel until you know what the zero fuel weight (passengers, cargo, empty jet–everything BUT fuel) is.

boeing-logo

Then subtract the zero fuel weight from 144,000 (max landing weight), deduct the planned enroute fuel burn and see what is left over–THAT , minus 2,000 pounds as a safety buffer (mine personally), and you’ll have a reasonable ferry fuel load.

The problem is, by the time I get to the jet, the “planned” fuel load–which doesn’t include the above calculation, because the zero fuel weight isn’t firm yet–is already aboard. If I do the math and find that we’ll be arriving weighing over the max landing weight, I have two choices: defuel (bad choice) before pushback or fly lower (dumb choice) to reduce the landing weight.

Both are bad options: if we defuel, that fuel must be discarded–trashed–because quality assurance standards wisely say you cannot take fuel from one aircraft’s tanks and meet the purity standards for another aircraft. So that’s money in the trash, plus a guaranteed delay to accomplish the defuel.

sunset contrail

The “fly lower” option works, but look what we’ve done: to “save” on return fuel, we’ve wasted thousands by flying at 24,000 feet versus 38,000 or 40,000 feet, just to squeak in under the maximum landing weight. And it’s bumpier and noisier down there among the cumulus clouds.

I always choose the second option, although I don’t always like landing at the maximum structural limit of the airframe on the shortest runway in the system. But, at least we can save the absolute maximum fuel for the return, rather than simply defueling into the trash.

On a longer runway, say LAX, stopping distance wouldn’t be a consideration, but the 144,000 pound limit is simply universal: doesn’t matter where you land, 144,000 pounds is max allowable. I need to intervene in the mathematics before the fuel goes on the jet outbound.

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The second, problem: the return. Dispatch may shave the arrival fuel to 5.0, which is sufficient, but there’s a catch. He’s planned us at a low altitude (29,000) because of chop reported in Arizona at the higher altitudes. If he’s right, at that lower altitude (FL290) I know from 38 years as a pilot that there will be both flight deviations for spacing or weather, or a choppy ride anyway.

So here’s what I personally do: I add another thousand for additional time and distance flexibility in case the turbulence forecast is correct–but I also plan to climb immediately to 39,000 feet to see for myself if the ride is choppy. That’s because I’ve just flown through that airspace inbound and know firsthand what the winds and the rides are, whereas the Dispatch and even the ATC reports are hours old. Plus, and again, this is based on over 22 years as an airline captain, I know we’re taking off at dusk and the entire thermodynamics of the air mass will change dramatically.

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So based on intuition, I’ll do the climb to 39,000 and “take the hit:” the early climb will be heavier and burn more fuel versus a later step climb, but my gut feel says we’ll regain that amount and more by cruising the longer time at the higher altitude. Notice I didn’t say 41,000, because I’m claiming a little pad because of the narrower range between high and low speed buffet at the max altitude. Plus, this time of year, surfing the jet stream at the higher altitudes will get you 510 knots or more across the ground. That’s the pay dirt of efficient flying.

Also, if I’m wrong, I did add the fuel pad up front. But I bet I’m not. The alternative is to fly lower (noisier, crowded, more weather) and experiment with the step climb–which burns fuel, too, and if you have to come back down because the ride’s bad, you’ll wish you hadn’t. But in the worst case, we’ll still land at DFW with a comfortable fuel pad.

And if I’m right, we’ll save a couple thousand pounds eastbound at the higher altitude and land fat on fuel. Fuel is time, to me, so nothing could be more important than more fuel.

Unless as I noted above, you’re on fire, or more realistically, as I’ve just explained, you’re trying to achieve the best outcome as efficiently as possible. Anything less is just plane fuelishness.

777 to

Common Sense Descents

Posted in air travel, airline pilot blog, airliner, airlines, flight crew, jet, passenger, pilot, travel with tags , , , , , , on October 18, 2013 by Chris Manno

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Getting 75 tons from cruising 8 miles up at 500 miles per hour down to walking speed at sea level is dependent upon one ever-changing three-point triangle.

That is, the dynamic relationship between altitude, distance and speed.  This relationship is as closely interrelated as a balloon animal: squeeze any one part, and the other two expand.

Descent planning, including mandatory crossing restrictions stipulating specifics in all three parameters would be simple if the triangle of altitude, distance and speed remained fixed. But it seldom does.

Here’s the simple, unrestricted problem: descend from 41,000 feet to sea level. Simple problem, simple math: a comfortable descent rate could be achieved in an idle power, clean (no drag, like spoilers) glide at 290 knots airspeed using the 3:1 rule 3 times the altitude in thousands to lose, or 3 x 41 = 123 miles.

Descent 1

But, here’s the first modification required: the max speed below 10,000 feet is 250. So, you have to allow more miles to decelerate from 280 to 250, plus more miles from 10,000 feet to touchdown because the descent will need to be shallower to keep the speed to 250 knots or less.

Yes, you could add drag in order to maintain the descent rate at the lower speed. But we’re planning the descent efficiently, fuel-wise, and also for passenger comfort: steeper descent angles and rumbly drag devices aren’t as comfortable as a clean descent. Plus, you’ll want to hold drag devices in reserve for when Air Traffic Control (ATC) tosses an unexpected restriction your way.

So anyway, now we have a straight line distance of 133 miles (I added 10 to slow down, remember?) for a clean descent. 290 nautical miles per hour is roughly 4.8 miles per minute. Couple that with a clean, idle descent rate of about 2,500 feet per minute.

The next problem is, however, the straight line. Most of the STARs (Star Terminal ARrivals) multiple lateral segments between a series of points, seldom in a straight line. What happens if you’re issued a revised clearance that shortens the route? That could easily shave off 20% or more of the flight distance, which also shortens the number of miles over which you can attain the descent. So, there’s the balloon animal: shorten the distance and you must increase the descent rate in order to cross the assigned point at the assigned altitude.

UKW STAR

What to do? First and easiest is to increase the speed, which will allow a higher rate of descent. That’s half the reason why I don’t plan descents at speeds over 300 knots–there’s no capacity to add speed if needed to increase the descent rate and accommodate the descent crossing restriction in light of the reduced miles available.

UKW STAR b

The other half is the ride: in the back end of the 737-800, particularly near the tail, all aircraft motion in turbulence, due to the stretched fuselage, are felt more intensely. If you encounter any choppiness at that speed, folks in the back could be tossed about pretty dramatically. Why risk that? Plus, if you plan a descent at 320 or 330–as the on board flight management computers often suggest–and then have to slow because of turbulence, you’re definitely not making your crossing restriction. Now you’ll have to call ATC and ask for relief–that screws up their traffic flow and means an off-course heading and as a result, a delay for you.

So how do you accommodate the shortened distance in real time? First, as soon as you execute the shortened distance in the Flight Management System (FMS), the system will recognize that the 3:1 calculation–the balloon animal of time, distance and altitude–is all out of proportion. The FMS just throws up its hands and switches from “Descent Path” mode to “VNAV Speed,” meaning it’ll hold the speed steady, you figure out how to get back to the descent path.

bug eye cockpit

So I switch the FMS to “level change” mode, meaning I want it to go after the altitude at the max rate with the speed set–then I set a higher speed. That achieves the best rate until, due to the higher descent rate, you re-intersect the normal path. And there’s where you must be on top of the ratios (speed, rate of descent, distance) in order to refuse a descent clearance you know you can’t rationally make.

That seldom happens with a shortcut route clearance, but often will happen if you’re restricted to your cruise altitude past a rational “top of descent” point. Therefore, you have to constantly be aware of the max descent available (with drag and higher speed), sensible (given the chop reports), tailwinds, which rob you of descent mileage, and be ready to refuse an altitude assignment that doesn’t fit those criteria. That only comes from keeping all of the ratios in not only accurately in your head, but also in the jet’s real time performance.

When any parameter changes, as they often do, you have to know how or if you can rationally accept or, even more difficult sometimes, refuse a clearance. I used to fly with a guy who specialized in “creative” refusals: when asked if we could cross a particular waypoint at a certain altitude that was mathematically (and balloon animal-y) unreasonable,  he answer, “We can, but we’ll have to leave the airplane behind.”

Better, I think, to manage the ratios, know what’s practical, plan ahead, and say “no” where required. Anything less, to quote Captain Randy Sohn, a revered name in the pilot world, “Would be considered bad form.” When it comes to balloon animals and jet descents, that just won’t do.

737 a wide

Motion Lotion: What’s the Commotion?

Posted in air travel, airline, airline pilot, airline pilot blog, airliner, flight crew, flight delays, jet, jet flight, passenger, pilot, travel with tags , , , , , , , , , , , , on June 27, 2013 by Chris Manno

“The only time you can have too much fuel is when you’re on fire.” –Anonymous Pilot

Those are words to live by, in the flying business–but jet fuel is expensive. In fact, it’s just about the largest expense in the operation of the airline, which is why it makes sense to use fuel as sparingly but sensibly as possible. But as a passenger, what’s it to you?

Well, for starters, this:

tstm day

Do we go around it? Above it? Through? You won’t like the last option, but fuel is the double-edged sword in this fight: more means we’re heavier, which limits our climb. Plus, going around the weather will burn more fuel, limiting our options at our destination:

fms crz

We’re at 36,000 feet now, which is just about the optimum altitude. “Optimum” is a moving target: as you burn off fuel enroute, the jet gets lighter and the wing can handle a higher altitude, which means the engines can operate at a lower thrust setting, thus saving fuel. We’re within 200 feet of the max if we climb to 38,000 feet to top the weather. We can wait till the “max” readout shows “380,” or really, from experience, we know that in the time it takes to request and receive the clearance, plus what we’ll burn in the climb, we’ll be at the correct weight. But, there’s always a catch.

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The airspeed tape on the left shows us a very narrow operating range at the top end of our altitude capability. That is, your range of acceptable airspeed is from about 212 to about 245. The “chain” above that shows the area of high speed buffet, meaning parts of the aircraft, above that speed, will begin to go supersonic. More importantly, though, in my mind, is Mach tuck: swept-wing jets tend toward a pitch down near the high speed limit, and guess what a pitch down does: your high speed becomes even higher. In a jet, particularly a passenger jet, if you don’t recover aggressively and immediately, you will not be able to stop what will become a dive.

On the bottom of the tape is the yellow line we call “the hook,” which is the slow speed stall. If you go below that speed, your airfoil will stall, and you will fall.

PFD coffin corner

So, at 38,000 feet, we have very little margin between the high and low speed buffet, requiring extreme vigilance on our part: turbulence, mountain wave action, or a drastic updraft of any kind can push us beyond either speed limit. Which is also part of the balancing act the captain must perform:

pfd coffin corner 2

I insert a slower Mach number in order to cruise more toward the middle of the range between the high and low speed limits. That, too, though, will affect our arrival time, won’t it? But that’s a balance I feel can be maintained, knowing that we’ve picked up some direct routing already. I’d rather sacrifice some time (and really, fuel) to gain a better pad between any adverse effects (mountain wave, thunderstorm up drafts, windshear, clear air turbulence) that could push us into either boundary.

And, I’ve already checked: the winds at the higher altitude are more favorable. To be even more accurate, I’ve requested a data-linked update to our flight management system, updating the projected winds the computer is using to calculate the times, distances and fuel burn it displays because what we data-linked into the system on preflight hours ago may not still be accurate:

fms crz wind update

The photo makes it hard to see, but the new, uplinked wind speeds are highlighted, all I need to do is push the “EXC” (execute) button and the entire nav calculation will be updated in a matter of seconds.

Climbing early has taken us out of more headwind earlier, so I believe the ETA will be largely unaffected. This hunch is borne out as we progress in our flight:

flt prog 1

We cross Pocatello, Idaho (PIH) six minutes ahead of schedule and up 700 pounds on fuel. If, however, the higher altitude winds were less favorable, we’d end up with the same result by going around the weather (more miles at regular cruise Mach)  as by climbing above the weather (less miles at a slower speed). The latter option is better, fuel-wise, as you can see from the fuel log above. But we’ll do whatever is safest and most optimum first, and worry about timing  later. Plus, if we don’t have what I consider a comfortable high speed-low speed margin at the higher altitude–we’re not climbing, we’ll just have to fly the additional miles (and minutes) around the storm.

It’s not just air miles between us and Seattle–it’s a constant balancing act of time, fuel, altitude and route. It all goes on steadily, quietly but relentlessly in the cockpit, but we all share the payoff in the end.

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Jet Wake Turbulence: Distance Ain’t Enough.

Posted in air travel, airline, airline pilot blog, airliner, jet, jet flight, passenger, pilot, travel, weather with tags , , , , , , , , , , , on January 19, 2013 by Chris Manno

Sneaking up behind me, are you? Here’s an infrared view you might need to heed: not the hotspots, but powerful the twin horizontal corkscrews of air current swirling off the wingtips of my jet. They’re wily, dangerous, and not to be trusted.

According to the Flight Safety Foundation, the vortices from a jet can have an internal rotation of up to 300 feet per second and often extend between 2 and 10 nautical miles behind a jet aircraft. The twin tornadoes–that’s literally what they are, horizontal but spinning powerfully–sink at a variable rate, between 300 and 500 feet per minute to an altitude  between 500 and 900 feet below the aircraft’s flight path and can persist for three or more minutes depending on the meteorological conditions.

That’s the problem, but hardly the full situation. Add to this hazard the closely constrained flight path of jet traffic in terminal areas. For instance:

SFO Q bridge

Approaching from the east, you’ll have a traffic stream from the west as well converging on the same runway complex. Not unusual as far as airports go–except that San Francisco International has less than the standard distance separating the two parallel runways. The FAA has waived the normal lateral separation, but you’d better keep that in mind nonetheless because that also means less than normal separation from the vortices of the aircraft next to you. Remember the outward spreading motion of those two tornadoes?

747 BAThis guy could be your dance partner all the way down final–and if he’s next to you, you aren’t entitled to the separation you’d get if he were ahead of you. Mostly, ATC will “advise” you to “use caution” for the heavy on the west runway, workload and time permitting–but they don’t have to.

And time and workload may not permit any advanced warning, and adverse weather can shroud the entire scene anyway:

SEA 16CLook at the inset on the bottom right corner: Seattle (one of my favorite destination cities!) has three parallel runways grouped together, and you won’t be told which of the three runways you’re landing on until you turn base to final about three minutes from touchdown. Would it make sense or even be possible to keep you informed of the heavies on all three inbound tracks? Add to the mix the typically obscured Seattle visibility, plus the added workload of programming and validating the FMS  sytem approach waypoints at the last second demanded by the late runway assignment and is there a possibility of situational awareness overload, on final approach: was that a heavy in front of us? Or on the outboard runway?

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Bring that back to San Francisco, where the standard runway separation is “waived,” like in MSP and many other cities. Now you’ve got a “buddy” laterally whose wake turbulence is drifting outwardly–just as yours is–and just because he’s not a “heavy” doesn’t mean he can’t roll you.

The ICAO worldwide “recommendation” for separation between a “heavy” and a “medium” following aircraft  (say, a 747 and a 737) is 5 NM (9.3 KM); between two heavies, 4 NM (7.4 KM). But the wild card not even mentioned in the separation rules is configuration and maneuvering: simply put, a “dirty” jet (flaps, gear) creates a nastier wake than a “clean” jet, and maneuvering distorts weight. That is, if I level off my 160,000 pound 737 with an addition one-half “G” force, I add to the effective weight another 40 tons of effect. And we’re a medium jet–imagine a heavy maneuvering dirty adding to his effective weight and wake.

That’s the science, now here comes the art. You know the reported winds at the field, but that’s a red herring: your encounter with wake turbulence won’t happen on the field. You need to be aware of the winds on approach, at your altitude. If the lateral wind at your altitude is blowing into the other jet’s wake, here’s what can happen: if the drift equals the outward spread momentum of the wake–and you have to figure the “dirty,” “maneuvering” wild cards mentioned above–the effect will either be to move the wake away more rapidly, or freeze it in place till it dissipates. Which is it?

You can’t see wake turbulence. You can’t be sure where it is, or know it’s strength based solely on the aircraft designation. And sooner or later, you’ll find yourself in it despite your best, most diligent precautions. What are you going to do, captain?

dusk b

For a true jethead like me, the first answer is always speed–but not so fast (pun intended): you’re configured with restrictive maximum flap speeds. If you’re in a final configuration with 40 degrees of flaps, you’re limited to 162 knots max. But the second instinct is valid: power.

throttle bugeye

But power alone is only part of the answer: what you’re not doing is going down. Why not? Because we know the vorticies are sinking. If we remain level or climb, we’ll escape the effects. What are they?

The Flight Safety Foundation survey of hundreds of wake turbulence encounters reveals uncommanded roll in trailing aircraft of up to 45 degrees at altitudes below 1,000 above the ground. One thousand feet is another magic number at my airline: stabilized approach  (on speed, on altitude, power set) is mandatory from 1,000 feet to touchdown. On glidepath–not above or below; not accelerating or decelerating, power set to flown speed and stable. And certainly wings level.

Which brings up the next problem of two major headaches you’ll instantly own. First, the right amount of counter-aileron, even if applied prudently, in many jets will bring up the wing spoilers to drop the low wing rapidly, inducing adverse drag, requiring more power.

Second, the option of climbing or even flying level is constrained by the published missed approach: protected airspace may be below you if you are above the missed approach altitude. And laterally, not only is there often parallel traffic, there’s also dangerous terrain you must always monitor and stay clear of:

MMMX ILS DME 5R

If you encounter wake effects in a level portion of the approach segment, prior to the aircraft ahead descending, at least you know his vortices will descend eventually below you and in this case, you normally feel the “burble” which now cues you: if the winds are keeping his wake aligned with your flight path, on glidepath you’re likely to fly into the tornadoes again when you’re slow and configured with speed-restricting flaps. Now look at the “mileage separation:” still think distance alone is enough? Still committing to the glidepath?

All of that doesn’t even consider the added, inevitable spoiler in every approach: weather. There’s more than terrain and aircraft for you to avoid in a very constrained airspace.

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There’s really only one good answer: up. And “up” may be a s simple as “no more down,” meaning a stopped descent or a slight climb to exit the effects. In any case, if you’re below 1,000 feet you’re no longer “stable” per the mandatory requirements. If you’re above 1,000 feet, you’ve just been cued that the mileage interval, given the meteorological conditions, nonetheless has left you vulnerable to the adverse effects of wake turbulence–and you’re not going to proceed.

Which means, in the immortal words of my old friend the Chief Pilot at my airline addressing my 1991 class of Captain’s “Charm School” (officially, “Captain’s Duties & Responsibilities”) as we sat rapt: you’re going to “get the hell out of town.” Amen.

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Back in the cabin? Expect the usual complaints about the delay for the second approach, plus a regular dose of exaggerated “there I was” tales about their wake turbulence encounter. So, don’t tell them–if you’ve done your avoidance and even escape properly, they’ll never know you even had a problem, which is the ultimate goal anyway: detecting and avoiding the problem in the first place.

The end result is, what they don’t know won’t hurt them, because you won’t let it. And that’s kind of why you get the privilege of flying the jet in the first place, isn’t it?

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