Archive for the travel 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

image

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.

image

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.

image

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.

image

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.

image

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.

image

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.

image

LGA: Landing on LaGarbage.

Posted in air travel, airline pilot blog, airliner, airlines, flight crew, pilot, travel with tags , , , , , , , , , , , , on March 22, 2014 by Chris Manno

fd1

Normally the jet handles smoothly with 3,200 PSI of hydraulic muscle powering the flight controls–but not flying down final at LaGuardia on a day when a gale blusters over the water as you slow and dirty up the jet. Sometimes, too, it seems like the eight foot tall winglets aggravate the tendency to weathervane in high crosswinds, and though the engineers might disagree, realtime air sense says otherwise.

Well, you’ve known about this wind for the last 1,200 miles; no surprise there. But foreknowledge doesn’t give you any more rudder throw or a definitive bank to set in gusty winds. Now the question is, will the rudder be sufficient, or the commensurate wing-low maneuver be too excessive to keep the engine pod on the low wing from scraping? Got to keep the nose tracking straight down the runway–can’t land in a crab, especially on a short, wet runway.

Xwind

On downwind, you can see RJs–regional jets–touching down smartly, but again, I wonder about their flying real estate: our wing has more acreage, thus not as clean, and I don’t care what the engineers might say (I think I know), our winglets hold the wing stiffer and the lessened flexibility translates more lateral motion to the jet. End result: rougher ride.

All of that comes with the territory: you know the limits and the options, so pre-planning is key to not looking stupid, or in less conspicuous terms, to arriving safely. And that is, arriving in the vicinity of LaGuardia: we’ve already discussed among ourselves, one approach, then clearance on request to JFK.

But why not plan enough fuel for two or more approaches? Isn’t there a good chance that if you fly down to minimums, then go-around, that on the next approach you’ll know exactly how to counter the winds?

AIPTEK

I’ve had that conversation with more than one new captain, when I was a Check Airman, taking the newly four-striped pilot through the initial flights of what one hopes will be a long, safe career as pilot in command. The “newly four-striped” distinction is the key–meaning, hasn’t scared the snot out of himself yet. Let me help.

I learned the hard way; uh, I mean, I heard of others getting caught in this line of reasoning. It’s borne of the can-do attitude, the feeling that you can handle anything and everything thrown at you and your jet, and you’d damn well better be able to. But the key is, you don’t want to have to.

I “discovered” a long time ago and have never challenged the fact that there’s nothing I’m going to see on that second approach that’s any different or better than on the first. And as important; no, MORE important, is this: no matter how much extra fuel you take on, it will require more.

Which puts you in the very ugly “all or nothing” mindset when you finally do get vectored back onto final approach, because inevitably you will have eaten up your mental fuel endurance padding (not your legal reserve, which isn’t even an issue–you NEVER stray into that) which means if you DON’T get it on the ground on this one, you’re really must-land at your alternate.

Manhattan

With that alternate being JFK, you’re going to look real stupid for declaring an emergency for fuel (swallow your pride–you’re out of options) in order to bust into their landing pattern ahead of the big rigs arriving from overseas. At least if you declare an emergency, you can demand the headwind runway–you’re already looking stupid, might as well take full advantage.

And sure, they’re all pretty at closing time, but in a jet, as captain, you’d better go ugly early and get out of town–or one of these long flight days, you’ll wish you had.

While on final, I’m cursing the powers that be for landing us with a direct cross while take-offs are being done on the crossing runway and thus, with a direct headwind, and I make a note to find out who and why this illogic (at least from a pilot standpoint) decides who gets the crosswind.

Because as a pilot, I’d prefer to face the crosswind on take-off in a state of increasing energy and control responsiveness rather than the reverse: slowing, losing energy and control effectiveness on landing. Plus, on take-off, once the wheels are off the deck, who cares: weathervane into the wind, that’s fine.

So a day later I grumbled about this to the most experienced pilot in the free world, a 747 instructor pilot and one of the few aviators entrusted with an open ATP–meaning the FAA has said he’s certified to fly any and every aircraft in the world.

Long JFK runway.

We both agreed that LaGuardia must use the same runways that are in use at JFK because they are so geographically close–you can’t have jets at LaGarbage on a south final with JFK launching north departures.

But then Randy offered the key, which I hadn’t thought of: JFK is launching heavies loaded down with fuel for 3,000 to 6,000 mile flights. And the long runway is key–so, LaGarbage conforms, and now I’m wrestling a crosswind on final.

Usually, below 200 feet is adequate to put in the cross-controls to be sure they’re sufficient and really, if you put them in much higher, the winds near the surface will be different anyway. But with LaGarbage having a “go ugly early” type day, and me seeing the runway only out of the far corner of the wind screen (smartass to the end, I ask my F/O, “Does it seem like we’re flying sideways to you?”), I start feeding in the rudder and dropping the upwind wing at 500 feet.

The wing shudders at the cross controls–winglets, I’m telling you, they don’t like it–and the upwind spoilers create an additional burble. My apologies to those passengers aft of the center of gravity, especially those near the tail, who’ve just asked themselves does it seem like we’re flying sideways? Can’t be helped–I ain’t the ace of the base, just an average, journeyman pilot who doesn’t do wondrous, spectacular things with the jet. I need time to get these controls set where they need to be.

AIPTEK

And truly, I feel no pressure at all, because Plan B is set: if this doesn’t feel right below 100′ (we’re flirting with the max demonstrated crosswind for the aircraft), we’re simply getting out of town to enter either JFK’s or Newark’s pattern with a fuel pad that makes the process simple and routine.

It’s not going to be pretty, because the runway is short and we have ironclad touchdown distance limits. Fine, but it will be on speed, no crab, and where it needs to be. Passengers will say the touchdown felt as if everyone in Manhattan simultaneously jumped off a chair, but no matter; safe, stable and however un-pretty that may be, let’s all just give thanks that Boeing makes one tough, reliable and durable jet.

Because besides flying back to DFW in less than an hour, we get to do this turnaround tomorrow and the next day, too.

At least tomorrow into LaGarbage it will be me watching and my very capable F/O wrestling the jet. Then he can ask, does it seem like we’re flying sideways? Yes, it does–and now you know why.

imageContact JetHead privately: see “About”

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

DSCF2947

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.”

IMG_0098

“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.

IMG_0095

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.

IMG_0105

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.”

flash

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.

IMG_2466

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.

IMG_4945

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.

IMG_0806
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.

IMG_1375

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.

throttles 2

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

fd1

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.

410

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.

IMG_2531

Summer Weather, Flight Delays and YOU.

Posted in air travel, airline, airline delays, airline pilot blog, airport, fear of flying, flight crew, flight delays, passenger, travel, travel tips, weather with tags , , , , , , , , , , , on May 29, 2013 by Chris Manno

fll sunsetYou can see the weather plain as day. But it’s miles away, right? How could that cause flight delays? Or worse, on a day that’s clear at the airport–yet your flight shows a one hour or longer departure day. Why?

Think big–or at least think far: miles translate into minutes in the air, and unlike your car on the freeway, we’re not creeping along under the storm–we have to get through it. At altitude, sure, we can go around weather or sometimes, even over a storm. But there’s the problem on take-off and landing: we are too low to do either.

First, let’s look at departure:

wx radar departure

Sure, the weather is nearly twenty miles away. But in flight time, we’re talking about maybe three minutes. Then what?

Normally, there are at least six eastbound routes available, but as you can see, due to the weather that extends from the north to the south, even twenty miles away, there are only two routes available to go east: straight north, or straight south. And guess what? They’re the same ones that will have to be used for the inbound aircraft–and they’re already in the air, many for over three hours inbound from the east coast, or up to nine hours from Europe. Guess who rightfully has priority on the clear routes?

Here’s more bad news for your outbound schedule:

lowgn4All of the departures–like the one pictured in above, and depicted on the navigation display with the radar image above–have very specific instructions for headings, altitudes and even speeds. But with the weather blanketing the area, no jet can comply with these very orderly instructions, so instead, air traffic controllers have to issue all headings and altitudes individually to each aircraft, checking to be sure that weather doesn’t interfere.

So the Air Traffic Control system must space jets by ten, sometimes ever twenty miles in trail to allow for the individual handling required, which means that instead of the usual interval of thirty seconds to a minute between launches, now takeoff will have to be 2-3 minutes in between.  You’re number ten for take-off? Count on at least 30 minutes, maybe more–especially if the weather arrives over the field while you wait.

flick

So, rather than have a traffic jam at the end of the runway waiting to take off, ATC issues all aircraft an “EDCT” (Expect Departure Clearance Time), or “edict,” as the acronym is typically mangled by crews, or even “wheels up time” in more common usage. This can usually mean an Air Traffic Control imposed delay on your pushback from the gate of forty-five minutes to an hour or more.

That presents another problem: while a delayed flight is held on the gate, the next aircraft scheduled for that gate will be delayed as well, either in the deplaning of passengers or the boarding of its next segment. At a major hub for any airline, there aren’t enough extra gates to make up for flights that must be held on their departure gates. If you arrive at the terminal and notice about double the normal amount of passengers milling about–that’s why: their outbound jet is waiting while a delayed flight sits on the gate, waiting for its EDCT time to roll around.

That’s what happens on the ground–here’s what happens in flight–which actually contributes to the confusion and delays on the ground.

wx radar arrivalSee the racetrack pattern near “CAPTI?” That’s where we’re going to be holding, hoping the weather clears within our allotted holding fuel, which is about 45 minutes. The airport is under the blob of storms at the convergence of all the lines.

The jet we’re flying is being ardently awaited at DFW by 160 passengers who plan to fly on it to LAX after we deplane our Dulles passengers at DFW. But, we’re now on our way–diverting–to New Orleans because DFW is still closed and won’t open for at least an hour.

Add to that the fact that my copilot and I started our flight day at 12:35pm. We leave New Orleans at 11pm, but have to fly all the way to Abilene before we can turn back to the east around the scythe of thunderstorms bisecting Texas. What’s normally a one hour and ten minute flight turns into two and a half hours, pushing my first officer to a 14 hour flight duty day, landing at 2:15am.

Not sure what happened to all the LAX-bound folks, whether they got a crew to fly the leg or not, or what happened to the connecting passengers on our flight arriving after 2am.

All I know is that this promises to once again be another season of crowded skies, summer storms, bone-achingly long flight days and above all, a challenge to everyone’s fortitude and patience. Now that you know the “what and why” of the weather story–maybe you could explain it to the guy seated next to you, wondering why everything is so messed up because of a little old storm?

ramp DFW

Flight Crew Talk: The Beatings Will Continue.

Posted in airline cartoon, airline pilot blog, flight, flight attendant, flight crew, jet flight, travel with tags , , , , , , , , , on May 15, 2013 by Chris Manno

What we have here . . . is a failure to communicate.

You wouldn’t think it would be so hard for crewmembers to communicate in flight–we have the technology; interphone, PA system, headsets and handsets–even our oxygen masks on the flight deck are wired for sound.

Nonetheless, once the cockpit door is closed, communication dies a slow, miserable death and as captain–it’s YOU taking the Cool Hand Luke beating from the Road Boss.

You don’t like it, I don’t like it–but that’s the way he wants it . . . so he gets it.

Let’s start with what’s usually the first salvo, fired right as we climb through ten thousand feet. That’s the magic end of “sterile cockpit,” which is the time period when flight attendants know non-essential communications with the pilots is prohibited because it’s a phase of flight requiring our concentration in the cockpit, and distractions are not welcome. I have answered the crew interphone when we’ve received a call below 10,000 feet with the admonishment, “We’d better be on fire if you’re calling me now.”

But above ten thousand, here it comes: “Can you turn down the air?”

Sigh. What does that even mean? More cold air? More hot air? Higher temperature? Turn down? So begins twenty questions: “What is it you want?” Sadly, though, the whole thing is our own fault or, honestly, usually the F/O’s fault.

ac tempThat’s because F/Os just CANNOT LEAVE THE TEMP CONTROLS ALONE. This is especially true of those with lingering brain damage from the MD-80, which essentially had a caveman vintage air conditioning system that DID require a lot of tweaking. On take-off, at full power, it could make snow in the back if you didn’t nudge the temp control valve off of the full-cold stop.

Not so with the Boeing–but F/Os HAVE to mess with it anyway–even though if the temp was comfortable on the ground, the Boeing will maintain that in flight.Nope–F/Os have to mess with it, have to do something, even though automatically, it’s fine left alone.

And that brings on the second failure to communicate. Inevitably, the F/O has to argue, usually tossing out, “Well, the duct temp says 75 degrees.”

phone cockpit

Unfortunately, the crew interphone system is a party line, and the flight attendants are listening. Sigh. They don’t give a damn about the duct temp–neither do I–they just know if they’re comfortable.  But that’s the pilot pigheadedness: we already know everything.

To reiterate, as I bump all three compartment temps down, just leave it alone, and give them whatever the hell they want. What do you care? You’re not back there.

Plus, use your head: this is a senior turnaround flight, with senior flight attendants swathed in layers of polyester, hauling carts and traipsing up and down the aisle. You think they want heat? You think I do? Sitting in the gazebo, direct sunlight–I constantly reach over and call for more cool air. You’re cold? Too bad–next flight, bring a sweater.

fd1

Now, let’s visit the cruise portion of our non-communication. The primary voice passengers hear is the PA, which announces information pertinent to our flight, like arrival time and weather. That’s key information for travelers and crew alike. But, there’s a catch: flight attendants can’t hear the PA.

For flight attendants, the PA is like a dog whistle: we can all hear it, average dogs that we are, but flight attendants are oblivious. You could have just said over the PA “we’ll be landing in one hour” and within minutes, the interphone chime will go off and the question will be, “When are we landing?” And not just once, because not only do flight attendants not hear the PA, they don’t talk to each other either. So you’ll get the same call two, maybe three times.

choiceLOGO

And never mind that you’ve given them a hard copy of the flight time before takeoff, and that they’ve typed that information into the touch screen at their station controlling the passenger information and entertainment system . . .

IMG_1822

. . . and that touchscreen, if they look at it, will tell them how much longer we have left in the flight. But, that would mean they’d have to look at their watch, then do the math. Especially when we’re landing in a different time zone–it’s easier to just call up front and ask me. Right?

Well, maybe not me. My answer is usually relative: “About ten minutes early.” Which means: look at your watch. This is your flight–know your own schedule.

Or, look at the gee-whiz panel at your station, counting down the minutes. Or, do the unthinkable: ask one of your colleagues in the back? Nah. Whether it’s the temperature or the time, rather than ask each other, just call up front. All of you–not one call, but four, because you can’t hear the dog whistle or talk to each other. Even had a fifth flight attendant, just riding the aft jumpseat home 130 feet behind me, ask me to “cool off the back.” Seriously?

Okay, it’s a given: we work together, fly together, even all talk–sometimes at once–to each other. We just don’t communicate very well. So, my new policy is this: any time the crew interphone chimes, I look to the F/O and say, “It’s for you.” He’s the one screwing up the temp anyway.

And at least I’m happy, and that’s a start.

sunset contrail

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?

IMG_2185

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.

photo-17

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.

dvt3

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?

IMG_4382

Follow

Get every new post delivered to your Inbox.

Join 4,597 other followers

%d bloggers like this: