Silver Wings Then Other Things: Part 3
This is Part 3 of the series putting you in the captain’s seat.
Want to start at the beginning? Click here.
I love the smell of jet fuel in the morning.
Okay, maybe right before noon–I don’t bid early flights and since I’ve been here over 25 years, I don’t have to do the buttcrack of dawn flights anymore. But it all leads to the same place: ready for take-off.
And whether that’s your first solo or your most recent take-off line-up, it’s the best part of the world ever: nose pointed down the line, strapped in tight, slight bend at the knees so as to have easy rudder throw in either direction, holding brake pressure on top of the rudder pedals, waiting for release.
Calm. All the engine instruments are flat-lined like a comatose patient, breathing; heartbeat but not much else. Idle RPM on both the giant fan and the turbine.
These new jet engines are mechanical and technological marvels, gi-normous Swiss watch-like machines: tolerances to the thousandth of an inch, spinning at 30-50,000 RPM for hours, tirelessly, core temps averaging blast furnace heat all the while. Each engine weighs over two tons, but puts out 27,000 pounds of thrust, so with both at full power, you have 26 tons of thrust at your fingertips for take-off or whenever you need it.
The pair of CFM-56 engines will gulp down nearly a thousand gallons of jet fuel between take-off and level off, but the marvel is, even heavy-weight we’ll climb to 38,000 feet in about fifteen minutes. That’s also attributable to the Boeing wing: they were wise enough to increase the size of the wing as they stretched the airframe. Not so with Douglas jets like the DC-9–they just added length to the fuselage and kept the original wing.
I like the feel of the fat, swept and cambered-up Boeing wing, which as a result of the lengthening has a lighter wing-loading than the stretched Douglas.
It just feels more stable and reliable both in the low-speed regime and almost more importantly, at altitude. So on take-off, there’s just a confidence you can bank on with the Boeing: it has power and lift to spare.
“Cleared for take-off” are the words you’re waiting for. Once you gang-bar the exterior lights, the First officer will call, “Before take-off checklist complete.”
You stand the throttles up and immediately, the CRT displaying engine instruments springs to life. The computers below the flight deck measure the throttle position and project where the RPM of both the giant fan and the subsequent rotors will be in a matter of seconds. They stabilize at 40%, then the actual rotor speed catches up as the engines snarl to life. Satisfied at 40%, I punch the take-off power button on the throttles and they move to the position that the engine computers say matches the temperature and the other parameters we programmed and will produce the thrust we’re expecting. I double check that they are within 2% of what I expect, then turn my eyes to the runway stretched out ahead.
It’s best to cast your eyes way down the runway so as to have a good peripheral awareness: engine failures will be most obvious from the initial yaw, plus, directional control at over a hundred miles per hour is best judged with a long view.
Now I’m steering with the rudder pedals, trying to just nudge the nosewheel–stay off the centerline lights with their annoying thumping–until between forty and seventy knots when the forty-foot tall rudder takes a good enough bite of the air to become effective at aerodynamic control.
“Eighty knots,” is the first callout, and it comes fast at take-off power. That’s the abort dividing line: up till eighty, I can consider aborting for various systems problems. After eighty, the abort response is different and because of the kinetic energy built up in our 70-ton freight train, stopping is much more critical a maneuver with serious consequences in terms of brake energy.
Plus, it’s not wise to try to arbitrate at over a hundred miles per hour whether a system indication stems from a failure that would affect our ability to stop: brakes, anti-skid, hydraulics, electrics.
That’s why I’m relieved when the aircraft announces “V1.” That means we’re beyond abort speed–and I’m thinking only of flying, even on just one engine if need be.
Almost immediately, the First Officer calls,”Rotate” and I ease the yoke back gently. Have to let the 737 fly off and get some tail clearance from the pavement before smoothly rotating the nose up to take-off pitch, which is shown in my heads-up display (HUD). Off we go.
When I see vertical velocity climbing in the HUD, plus increasing radio altitude numbers, I simultaneously give the hand signal (flat open right palm moving up) and say, “Positive rate–gear up.” The hand signal is in case my voice is blocked by radio chatter or other extraneous noise.
The HUD’s also showing me the energy building on the wing, plus the speed trend. Call for the flaps up before the limit speed, engage vertical navigation (“V-Nav”) at 2500 feet. Track the departure outbound, centering up the radial. I sneak peaks down from the HUD to the Nav display so as to anticipate the turns ahead. Roll into the turns easy–the 737 flies really tight and responsive–and carve out a smooth arc.
First milestone: ten thousand feet. Roll in some nose-down trim so as to accelerate beyond the 10,000′ limit of 250 knots. A quick check to be sure that the cabin is climbing and that fuel is flowing properly: above 10,000′ we can burn center tank fuel if we didn’t on take-off or if there was less than 5,000 pounds at take-off; less than 3,000 pounds now and you reach up and open the fuel crossfeed manifold and turn off the aft fuel boost pump.
Eyes back on the road. Trim. Smoothness. Coffee.
Before you know it, the chronometer says around 18 minutes elapsed time and the altimeter reads 40,000 feet. Trim it up, level and smooth, trim out any yaw, engage the number 1 autopilot. Check the fuel burn, the fuel flow and the quantity. Cabin pressure stable at the correct differential value. Nav tracking properly. Cool: we’re cruising.
So now, here’s you:
No, not just punching the time clock–counting fuel flow, measuring miles remaining against fuel and miles per minute. Print the uplink of the destination weather. Was your forecast correct? No, you didn’t do the weather forecast–you predicted what fuel you’d need on arrival for the approach in use. Kind of glad to have a little extra in the hip pocket, right? Conservative fuel planning.
Note the climb point and more importantly, the gross weight where that can occur. Pay attention; note when it arrives early and use it: tailwinds or headwinds shift the point, but track the weight.
Now it’s time for the P.A. Nobody cares or pays attention–especially the flight attendants who will ask “what’s our ETA” even though you just announced it. Whatever. It’s always partly cloudy, make up a temperature, read off the latest ETA, “glad to have you flying with us today; for now, sit back, relax” blah-blah blah, get ready for the approach.
You know the arrival winds. You got the uplinked current weather and terminal information. Set up the approach in the course windows and frequency selectors. Yes, it can change while you’re enroute, but now is the time to set up the approach and get it straight in your head.
There’s the art in what you do: translate this schematic into three dimensional movement in pitch, bank and roll. Each approach has its own peculiarities–so start thinking it through now.
Meanwhile, however, just a constant flow of navigation, fuel flow and performance considerations. Keeping a fuel and navigation log, constant contact with Air Traffic Control:
That and maybe some of the catering from First Class provisioned as “Crew meals.”
The best catering of breads and desserts is out of Mexico and Canada, I think. But at any rate, it’s probably good to stay “calorized” as a survival tool: time changes, sleep disruptions, long hours, extremes of climate and especially the prolonged hours in a low-humidity cabin–it all takes a toll, physically. And flight crews work in that realm week after week. At least you can buttress your health with the caloric energy you need. It’s not always available between flights.
Manage the fuel. Weather radar and traffic watch. Ride and wind reports, both from other aircraft and uplinked from our Ops center. navigation–course modifications, shortcuts, direct clearances, higher altitudes when we’ve burned off enough fuel.
So it goes for hours on end.
The nav systems are plotting a descent already. They have drawn an imaginary line from altitude to our destination and I can see constantly the angle and the rate of descent changing as we draw nearer. I’m going to induce the descent–with ATC clearance, of course–a little early, maybe fifteen miles or so depending on winds, to make the descent a little flatter and more comfortable in the cabin. Besides, the automation doesn’t account for ATC restrictions added to those already published. Let’s get ahead of the game.
HEFOE Check: Hydraulics, electrics, fuel, oxygen, engines; periodic checks, the mantra from the Air Force days–nostalgic, but appropriate still in an airliner at the top of descent. Which, I’ve decided in my mental picture of the descent angles, distances, speeds and times, is now.
“Tell them we’d like lower,” I say to the First Officer. He nods, instinctively aware that it’s about time to start our descent. This is where passengers in the cabin notice the slight decrease in engine noise and a bit of a nose-down tilt.
The shoulder harness come back on in the cockpit; headsets replace overhead speakers and boom mikes take over from the hand mikes. Approach plates are reviewed on more time; crossing altitudes and speeds, intercepts and radials. This is the fun part: translate the myriad of plotted out instructions into a graceful series of maneuvers culminating with a safe touchdown, then dissipating the kinetic energy of sixty tons thundering down the runway at about one hundred and sixty miles an hour, bringing the whole remarkable aircraft to walking speed, then to a gentle stop at the gate. Piece of cake.
Next week, Part 4: the approach and landing.