Who's Afraid Of A Dead ASI?
If you’re among the aviation illuminati, you will know about the Swiss cheese theory of accident incidence. That’s where the holes in multiple slices of cheese line up to allow the determined accident to sail straight through to the bottom of that smoking hole where you find yourself picking shards of your iPad out of your forehead amidst the smoldering contents of your genuine AOPA logo flightbag. With luck, that new ADS-B will have kept ticking, so you’ll have a WAAS-assisted crater grid reference. Next time, try the Havarti.
Lately, like this morning, I’m beginning to believe the Swiss cheese theory also applies to pilot brains as we age because I otherwise have no explanation of why how I learned to fly without an airspeed indicator popped into my head. But it probably had something to do with the Lion Air accident, in which faulty instrument indications may eventually be a factor.
My exposure to airspeed-indicator-optional flying occurred in primary training, which I did at a military club at Ft. Bragg, mostly with civilian instructors. But stage checks were sometimes conducted by military pilots and I did my post-solo review with a just-back-from-Vietnam Warrant Officer named, if I recall correctly, Larry. Loach pilot; big black-and-yellow Cav patch, plus a CIB and you didn’t see many of those on Warrants. I regret not asking how he got it. By the way, Loach referred to the OH-6 Cayuse. Nobody called them that, because Cayuse sounded like someone’s butt. They were Loaches.
Ten minutes into my flight with Larry, he got bored with stalls and steep turns, produced a carefully folded dollar bill and covered the ASI. I repeated all these maneuvers without airspeed reference. Big deal. Ten minutes later, bored again, he took the airplane and said, “Lemme show ya something.” We dove straight for the Cape Fear River and spent the next 40 minutes strafing rapids, trees and sandbars at 10 feet. Maybe less.
The Law of Primacy being what it is, this left certain indelible impressions on the 19-year-old version of me. One, low flying is exhilarating and you can do it without people yelling at you. Two, you don’t need an airspeed indicator to fly a little piston airplane and probably not much of anything else, either. Three, just-returned Loach pilots were adrenaline starved and Warrants in general were the crazy sumbitchs we always thought they were, making me respect them yet more. And if you ever have cause to talk to a veteran wounded in combat and yanked out by a Dustoff, you’ll get a master class in respect.
In my instructional career, I have passed on that ASI-less drill with mixed results. Just a WAG, but I’d say about a third of pilots find it no big deal to take off, fly, maneuver and land without airspeed reference. Maybe another third can do it, although not comfortably. The remaining third are, in varying degrees, nervous, reluctant and terrified. I once had a Mooney owner refuse to land the airplane until I peeled the soap dish off the ASI. OK, pard, but I’m withholding your Steely Eyed Aviator merit badge.
There’s really nothing to flying without ASI, even in IMC, but definitely when you can look out the window. Level the wings, select a power setting you know will deliver a ballpark airspeed and motor on. Airspeed as an absolute is usually irrelevant. We’ve just learned to use it as a surrogate for stall awareness, since not everyone thinks about stalls the way they should, which is angle of attack.
Now that AoA indicators are making inroads, well, bully. But let’s not substitute one crutch for another. If you can’t look out the window and fly the airplane on the wing without reference to any instruments, your primary instructor was an idiot. Maybe that’s too harsh. But you were certainly shortchanged in the fundamentals. But he may still have been an idiot.
Landing without ASI is no different. Just trim the airplane for what looks like a familiar attitude, set a known power setting and carry on. You’ll probably be a little fast because trying to suck the seat cushion through your sphincter inhibits concentration, but just relax. If you practice this—and no surprise, I’m saying you should—you’ll learn to nibble the speed back to near normal and be comfortable doing it. The point of doing this is not so much to prepare for losing the ASI—a relative rarity—as it is just refining your hand-eye feel for the airplane. We used to call this stick and rudder, but now we just have autopilots do most of it so we can deepen the surface eye glaze caused by staring at glass all the way to the brain stem.
In the background, I’ve been corresponding with what I might call old-school airline pilots, which is to say people who grew up learning to fly piston airplanes and carried those habits right into the cockpits of Boeings and Buses. They’ve been guiding my reporting about the Lion Air crash by noting that big airliner or not, you can still grab the controls and actually fly the thing. Boeing even has a published procedure for flying with unreliable airspeed: Set pitch to 4 degrees and N1 to 70 percent. I dunno; not that different than a Bonanza.
Then again, at the higher levels of automation known only to the pilots of Airbuses, airplane designers have done their level best to divorce the pilots from feeling wind over the wings. During the course of my research on Lion Air, I came across an incident earlier this year in which the crew of a Malaysia Airlines A330 managed to takeoff with all three pitot covers in place. This is not so much Swiss cheese as cottage cheese liberally dolloped in the space between the ears.
But hey, who hasn’t done this? Actually, I haven’t, but I did take off once with the cowl plugs still in place, a story for another time. In most airplanes, a covered pitot tube is a nuisance, but not cause for alarm. Ah, but an Airbus is different. With no pitot input, the checklist calls for turning off all three Air Data Reference systems. And with no ADRs, the gear can’t be lowered except through a backup gravity system which, inexplicably, locks out nosewheel steering. The gear doors, which remained open due to the gravity drop, were damaged during the overweight landing.
I doubt if even Larry could have found that entertaining.