Ask the pilot

Was Obama in danger when his plane made an emergency landing? What's an "unforgiving" aircraft? The pilot answers readers' burning questions.

Published September 19, 2008 10:00AM (EDT)

Now and then this column needs a slap upside the head -- a reminder not to forgo the tried-and-true format that got it started: fielding questions from the traveling public.

In your article about last month's Spanair crash, you state that the MD-80 series aircraft is perfectly safe to travel in. But you also describe it as "not the newest, most advanced, or quite frankly the most forgiving plane in the sky." Could you briefly explain what you mean by that? "Not the most forgiving" sounds more than vaguely ominous.

That's a good, simple question with a long, knotty answer that is bound to be misinterpreted. But I'll give it a try anyway, beginning with the classic disclaimer that all commercial jetliners are remarkably safe. I'm reminded of the time I accused the ATR turboprop of being "fragile," or when I called my old DC-8 cargo jet a "relic." This is a pilot being colloquial. Don't take such statements literally.

It shouldn't be surprising that a pilot might prefer one aircraft type over another. Airplanes, like any large and complex machine, have their own personalities, as it were, characterized by various quirks and idiosyncrasies. Some models are less operator-friendly than others.

With respect to the MD-80, you could say, for example, that the plane's internal systems and cockpit layout are not as intuitive as those found on planes designed by Boeing or Airbus. The auto-flight system, to pick one, is a pain in the neck, and certain switches are found in odd, seemingly random places. There's an awkwardness to the plane's engineering.

Handling-wise, the MD-80 has a small wing with minimal high-lift devices, meaning it needs to perform certain maneuvers at relatively high speeds. It is sluggish in turns, especially when slow, making strong crosswind landings a tad tricky. The wings are placed very far aft, thus so is the center of gravity, which means the rudder is less effective at counteracting asymmetric thrust with a failed engine. Although its tail-mounted engines have a close-to-centerline thrust vector, an engine failure requires more rudder correction than would be needed on many planes with wing-mounted engines.

As you're aware, these sorts of traits in no way make the MD-80 unsafe. But they do make it more challenging and work-intensive. Many crews enjoy the MD-80 (the cockpit is quiet and surprisingly roomy, among other good points), but on the whole it is not a pilot's favorite. The thing I enjoyed least during my brief tenure as an MD-80 first officer was a constant toilet smell; only a thin bulkhead separates the first-class lavatory from the flight deck.

Incidentally, reports now say the Spanair tragedy in Madrid was caused by improperly set flaps -- more on that in the weeks ahead. Once again early speculation, which in this case focused on engine problems, including eyewitness accounts of fires and explosions, missed the mark completely.

In July, Barack Obama's campaign plane, an MD-80, made an emergency landing after the crew apparently lost pitch control. I'm curious how close you think we came to possibly maiming or losing Sen. Obama and his staff in a crash.

Pitch refers to a plane's rotation about its lateral axis. That is, its nose-up, nose-down motion. Pilots adjust pitch primarily by moving the steering column forward or aft, which in turn moves the hinged portion of the plane's horizontal tail -- the elevators. Loss of pitch control would be extremely serious, if not catastrophic. But that's not what happened.

The MD-80 carries a large inflatable escape slide inside the tail cone. During an evacuation, the tail fairing drops off and the slide extends to the ground. Well, on Obama's plane that slide malfunctioned and deployed during flight. The tail cone did not detach, and the inflated slide, wedged within the tail structure, put pressure on some of the elevator cables. The controls became stiffer and less responsive. Unsure what they were dealing with -- and possibly remembering the crash of Alaska Airlines Flight 261 eight years ago, in which a stabilizer malfunction caused a terrible crash -- the crew opted for an unscheduled landing in St. Louis.

Now, had the slide deployed a slightly different way, could it have put further pressure on the controls, perhaps rendering them dangerously unresponsive? I don't know.

Meanwhile, big surprise, try Googling any variance of the words "Obama," "plane," "conspiracy" and "sabotage," and behold the chatter. Forgive me if this is in bad taste, but just imagine what would have erupted following a more serious accident. One of this column's first installments took on the conspiracy theories in the wake of the accident involving Sen. Paul Wellstone. Wellstone was an up-and-coming Democrat killed in a plane crash in 2002.

This past summer, a Delta flight from JFK to Salt Lake City blew a tire on takeoff. Instead of continuing to their destination, the crew circled for several minutes to reduce weight, then returned to JFK. Then, a few weeks later, the same thing happened to an American flight headed from Los Angeles to Toronto. The plane blew a tire, circled, then returned to LAX. This doesn't make sense to me. Why not proceed to the intended destination? Salt Lake City and Toronto are large modern airports that are perfectly capable of handling something as minor as a landing with a flat tire. The passengers would have gotten to where they were going, and thousands of gallons of fuel would have been saved.

True, but there are several factors in the return-or-continue decision. Runway length is one of them -- longer is always better, and JFK and LAX have some of the longest runways around. Sure, Salt Lake City has some pretty big runways as well, but the airport's elevation (i.e., thinner air) entails landing at a higher speed. With a landing gear problem, it's best to touch down as slowly as possible.

Weather is another issue. Will it be raining or snowing at the destination? Will the runways be slick? Then you have airport crash-and-rescue capabilities and, last but not least, the airline's on-site maintenance capabilities. Los Angeles is a hub for American Airlines. Changing the tire on a jetliner is a little more involved than changing one on a car, and returning to LAX meant the repair would be faster, easier and more affordable. And what if the blown tire has caused further, unseen damage? Imagine if the plane gets all the way to Toronto and they discover damage to the landing gear assembly, an engine or a wing surface? Not only would passengers on the return flight have to be re-accommodated, but now the jet is stranded at an out-station in need of substantial and expensive repairs. Further reading: everything you were afraid to know about landing gear and tires.

Being a frequent flier, I have a lot of time to ponder completely ridiculous scenarios, this particular question being the most recent: What would happen, during takeoff or landing, if every passenger on a plane stood and began jumping up and down?

Obviously, they would be shipped to Guantánamo Bay. Apart from that, it somewhat depends on the size of the plane, but assuming an average-size jetliner, nothing would happen.

It's easy to overestimate the relative weight of passengers and their belongings. The 767 that I fly has a maximum takeoff weight of 407,000 pounds. A full complement of passengers and their carry-ons works out to just under 40,000 pounds, or less than 10 percent of the total. Coming in to land, even with most of the fuel burned away, it's still only 15 or 20 percent. Even on a regional jet that weighs, say, 50,000 pounds, a load of 50 people and luggage is 9,500 pounds, or only about 20 percent of the total.

Passenger and luggage tallies are approximations. Except on the smallest planes, passengers are not required to divulge the specs of their waistlines, and instead airlines use standard values for both people and luggage -- 190 pounds per person (including carry-ons) and 30 pounds per checked bag. This is adjusted slightly higher during winter to account for heavier clothing (please don't ask me about trans-climate routes).

Jumping up and down is one thing; should a large number of people suddenly rush from one end of the plane to another, shifting its center of gravity, that's more serious -- though still not dangerous in most situations. Center of gravity data is computed prior to every takeoff, and must fall within certain parameters. The plane's stabilizer trim, which fine-tunes pitch control, is then set accordingly.

- - - - - - - - - - - - - - - - -


Re: U.S. airline service woes

I found myself flying from Papua New Guinea to Columbia, S.C. -- a 42-hour journey on five different airlines. Qantas and Singapore Airlines offered generous amenities and friendly service. Even humble Air Niugini managed smiles and friendliness along with its jungle survival kits. By comparison, the Northwest leg from Amsterdam to Detroit was among the worst flights I have ever been on. The crew served a small meal and beverage service 30 minutes after we took off, then went and hid for eight hours. One flight attendant shouted at a little girl. While I have long known that U.S. carriers are immensely worse than their international counterparts, never has it been put in such stark relief as during that 42-hour journey.

-- Sarah Martin

Do you have questions for Salon's aviation expert? Contact Patrick Smith through his Web site and look for answers in a future column.

By Patrick Smith

Patrick Smith is an airline pilot.

MORE FROM Patrick Smith

Related Topics ------------------------------------------

Air Travel Ask The Pilot Business