Cockpit Confidential (8 page)

Windshear got a lot of press in the 1970s and 1980s, when relatively little was known about them. The crash of Eastern flight 66 in New York in 1975 is considered the watershed accident after which experts began to study the phenomenon more carefully. Since then, windshear has become relatively easy to forecast and avoid. Major airports are now equipped with detection systems, as are planes. Pilots are trained in escape maneuvers and can recognize weather conditions that might be hazardous for takeoff or landing.

This would have been a “compressor stall,” a phenomenon where airflow through the engine is temporarily disrupted. The compressors of a jet or turboprop consist of a series of rotating airfoils—each blade is, in essence, a tiny wing—and if air stops flowing smoothly around these airfoils or back flows between the sequential stages, your compressor is stalling. It
can
damage an engine, but chances are it won't.

Miscellaneous engine peculiarities, compressor stalls included, can sometimes put on a show. Aside from a bang, you might see a long tongue of flame shooting from the back, or even the front, of the cowling. Tough as it might be to accept, the engine is neither exploding nor on fire. This is the nature of a jet. Any time the engine is running, fuel is combusting, and certain anomalies will unleash this combustion rather boldly.

The stalling compressors of an Alaska Airlines 737 once made the news when, by chance, a burst of flame was captured by somebody's camcorder on the ground. The video was alarming, but the stall was effectively harmless. And when this sort of thing happens at the gate or during taxi, passengers have been known to initiate their own evacuations. One such panic took place aboard a Delta plane in Tampa, Florida. A stampede of frightened passengers made for the exits, refusing to heed flight attendant commands. Two people were seriously hurt.

While it may surprise you, it's not the least bit uncommon for jets to descend at what a pilot calls “flight idle,” with the engines run back to a zero-thrust condition. They're still operating and powering crucial systems, but providing no push. You've been gliding many times without knowing it. It happens on just about every flight.

Obviously an idle-thrust glide is different from the engines quitting outright, but even then, the glide itself would be no different. There's no greater prospect of instant calamity than switching off the engine in your car when coasting downhill. The car keeps going, and a plane will too. In fact, the power-off performance of a large jet is better than that of a light Piper or Cessna. It needs to glide at a considerably higher speed, but the ratio of distance covered to altitude lost—close to 20:1—is almost double. From 30,000 feet, you could plan on a hundred miles worth of glide.

Total engine loss is about as probable as a flight attendant volunteering to give you a shoe-shine, though it
has
happened. Culprits have included fuel exhaustion, volcanic ash, and impacts with birds. In several of these incidents, crews glided to a landing without a single fatality or injury. In other cases, one or more engines were restarted before reaching the ground.

Pressurization is one of those things that few folks understand and that many fear needlessly. Something about the word “pressurization” causes people to picture the upper altitudes as a kind of barometric hell. I've been asked, “If the plane wasn't pressurized, would my eyes pop out?”

Cruising in an airplane is not the same as dropping to the Marianas Trench in a deep-sea diving bell. The cabin is not pressurized to keep your eyes in but to allow you to breathe normally at high altitudes, where the air is thin and oxygen levels are very low. The system uses air drawn from the compressors in the engines and regulated through valves in the fuselage to squeeze the rarified, high-altitude air back together, recreating the dense, oxygen-rich conditions at sea level. (Or close to it. Pressurizing all the way to sea level is unnecessary and would put undue stress on the airframe, so the atmosphere in a jet is actually kept at the equivalent of 5,000 to 8,000 feet, meaning that you're breathing as you would in Denver or Mexico City—minus the pollution.)

That's all there is to it.

Great, you're thinking, but what about a
loss
of pressurization: the plastic masks dropping, people screaming…

Yes, a cabin decompression is potentially dangerous. During cruise, depending on the altitude, there's a differential of somewhere between 5 and 8 pounds per square inch between the pressure inside the plane (high) and the pressure outside (lower). You can think of the fuselage as a sort of balloon, with up to 8 pounds of force pushing against every inch of it. Introduce a hole or a leak into the picture, and you've got a problem. Loss of pressure means loss of oxygen, and if this happens explosively, such as from a bomb, the resultant forces can damage or outright destroy the plane.

However, the overwhelming majority of decompressions are not the explosive kind, and they are easy for a crew to handle. Odd things have happened, such as the bizarre Helios Airways accident in 2005, but crashes or fatalities from pressure problems are extremely uncommon, even with a fairly rapid decompression brought on by a hole or puncture.

If cabin pressure falls below a certain threshold, the masks will deploy from the ceiling, exposing everybody to the so-called “rubber jungle.” Should you ever be confronted by this spectacle, try to avoid shrieking or falling into cardiac arrest. Instead, strap your mask on and try to relax. The plane will be at a safe altitude shortly, and there are several minutes of backup oxygen for everybody.

Up front, the pilots will don their own masks and commence a rapid descent to an altitude no higher than 10,000 feet. If the descent feels perilously fast, this isn't because the plane is crashing: it's because the crew is doing what it's supposed to do. It might be jarring, but a high-speed emergency descent is not unsafe by itself.

One afternoon I was working a flight from South America to the United States. All was quiet high over the Caribbean, when suddenly there was a loud whooshing sound that seemed to come from nowhere and everywhere at once. I could feel my ears popping, and sure enough, a glance at the instruments showed we were quickly losing pressurization. The captain and I put our masks on, took out the book, and began to troubleshoot. Part of that troubleshooting involved one of those steep descents. Commencing such a drop is a multistep process: set 10,000 in the altitude window; select “flight level change” from the autoflight panel; increase the speed command to a point slightly below maximum; deploy the speedbrakes; retard the thrust levers to idle… To the passengers, I'm sure it felt like a roller coaster, but everything was carefully coordinated. The autopilot was engaged the whole time, and no limits were exceeded.

Should a pressure loss occur over mountains or other high terrain, pilots will follow predetermined depressurization routes, sometimes called “escape routes,” that allow for a more gradual descent, in stages. Even if crossing the Andes or the Himalayas, there is
always
the opportunity to reach a safe altitude before supplemental O
₂
runs out.

The short answer is no. No commercial aircraft is unsafe or anything remotely close to it. The long answer is more nuanced. Whether regional aircraft are, on some level,
less safe
than mainline jets is open to debate. There is no practical reason why anybody should outright avoid smaller planes, but it's still a debate worth having:

Size, strictly speaking, isn't the issue. I can't speak to claustrophobia or absence of legroom, but there is almost nothing about an airplane's size that correlates one way or the other to the likelihood of it crashing. A modern turboprop or regional jet can cost tens of millions of dollars, and if you haven't noticed, that money isn't going into catering and sleeper seats; it's going toward the same high-tech avionics and cockpit advancements you'll find in a Boeing or Airbus. These planes might be small, but quaint they are not. And, so you know, pilots bristle at the term “puddle jumper” the same way an environmental scientist bristles at “tree hugger.”

Of course, a plane is only as safe as the crew flying it, and there has been controversy over the training and experience levels of regional pilots. With wages and working conditions at regional carriers notoriously substandard, it has become increasingly difficult for these companies to recruit and retain experienced pilots. New hires have been brought aboard with surprisingly low flight time totals. More about this in chapter four (
see regional pilots
).

Love them or hate them, RJs are here to say. In the United States, RJs now account for more than 50 percent of all flights. There are literally dozens of different “Express” and “Connection” affiliates hitched up with the majors. Unbeknownst to most travelers, these carriers operate independently from the majors, sharing little more than a flight number and paint job. They are subcontractors, with entirely separate management structures, employees, and training departments.

If you're impressed by big numbers, you'll be grabbing for the high-lighter when you find out a 747 tops off its tanks at just over 45,000 total gallons. It takes around 11,000 to fill a 737 or A320. A fifty-seater with propellers might hold less than a thousand gallons. Paltry in comparison, but still enough to drive your car from Washington to California six times. Fuel is stored in the wings, in the center fuselage, and even in the tail or horizontal stabilizers. The cargo jet I used to fly had eight separate tanks, and much of my job was moving their contents around to keep them balanced.

Flights rarely depart with full tanks, however, as lugging around excess tonnage is expensive, impractical, and limits cargo or passenger payload. The amount to be carried is a somewhat scientific undertaking, with some hard-and-fast rules. Crews do not ballpark the load with a cursory glance at a gauge, as you might do in a car before a road trip. It's the dispatchers and flight-planning staff who do the calculating, in strict accordance to a long list of regulations. They are intricate, especially when flying internationally, and can vary from country to country (a plane is beholden to its nation of registry, plus any local requirements if they're more stringent), but the U.S. domestic rule is a good indicator of how conservatively things work: There must always be enough to carry a plane to its intended destination, then to its designated alternate airport(s), and then for at least another 45 minutes. The resulting minimum is nonnegotiable. Sometimes, if weather criteria so dictate (the particulars are very specific), two or more alternates need to be filed in a flight plan, upping the total accordingly. If traffic delays are expected, even more will be added. And although dispatchers and planners devise the figures, the captain has the final say and can request more still. Carrying surplus fuel costs money, but not nearly as much as the hassles of diverting.

The preflight paperwork includes a detailed breakdown of anticipated burn, which is carefully tracked once the flight is underway. Remaining fuel is compared to predetermined target values as the flight progresses from waypoint to waypoint. The totals are monitored by the crew and dispatchers, the latter receiving updates via datalink transmission. You have a solid idea, well in advance, of exactly how much fuel you'll be landing with. If for some reason that number drops below or close to what's legally required (unexpected headwinds, a mechanical issue), there's ample time to plan a diversion.

Do airlines cheat to save money? You'll periodically come across scandalous-sounding news stories describing planes dispatched with “reduced fuel loads,” allegedly resulting in unsafe situations when these flights are hit with delays and holding patterns. Carriers are, in some situations, cutting back on the carriage of extra fuel, which is heavy and expensive to haul around. But note the word
extra
. It's the above-and-beyond fuel that airlines look to reduce, not regulatory fuel. While these cutbacks allow for less wiggle room, they are not dangerous. The penalty isn't crashing; it's having to divert earlier than you'd like, with logistical hassles for passengers and crew.

Given all of that, the idea of running the tanks dry would seem far-fetched. Yet a small number of fuel depletion accidents have occurred. Understanding how and why they occurred would entail pages of boring (for both of us) analysis that I haven't the space to explore. These were once-in-a-billion mishaps. Most of them happened decades ago, and suffice it to say the stories were a lot more complicated than an airline being cheap or a copilot waking from a nap and exclaiming, “Holy shit, we're almost out of gas.”

People will sometimes complain to authorities about what they take to be streams of jet fuel trailing behind airplanes low to the ground. What they're actually looking at are trails of water vapor—the condensed cores of the vortices spinning from the wingtips (
see wakes and vortices
). This is common when humidity is high. You will sooner see sacks of hundred-dollar bills being heaved overboard than fuel being spit away for no good reason.