Who's Afraid Of A Dead ASI?

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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.

Comments (24)

The preceding article written by "One of the Pauls." But which Paul? Cast your ballot here!

Posted by: ANDREW PATTERSON | November 28, 2018 5:25 PM    Report this comment

Pegged Mr. Berge in first sentence. Really enjoy both.

Posted by: John Savant | November 28, 2018 6:24 PM    Report this comment

It ISN'T 'Id Est' ... it's the REAL Paul.

The guy who taught me to fly went on to become an A330 Captain. He told me that he HATED those things for crazy software algorithms that required insider knowledge of how to make the airplane do things despite itself. Once he was in the cockpit, he took off his airline hat and put on a Boeing hat just for spite. HIS favorite airplane was the 727-100.

Posted by: Larry Stencel | November 28, 2018 9:40 PM    Report this comment

I like Swiss cheese on my ham sandwich, you can keep your cottage cheese, "yuk."
That being said, there's just plane :) to much crap in th cockpit in the name of safety. It's not working. It's actually creating situations for accidents to happen. The pilots brain is Swiss cheese quickly turning to cottage. It's not just aviation where this is happening, I see it in the construction industry also. In the name of safety the so called "Swiss cheese safety experts" are making some sites less safe. We're beyond the point of diminishing returns, we're now into the world of negative returns. The harder you try the worse it gets.

Posted by: Tom Cooke | November 29, 2018 5:32 AM    Report this comment

A-Paul-ing! Nice job, Berge.

I'll add that, in the little Pipers, you'll need to disable the electric stall-warning horn. I'm fond of simply turning off the master switch, immediately after takeoff... late in the student's first night flight, while doing closed traffic. (I coordinate this with ATC, so light-gun signals get tossed in, too).
You'd be amazed ( ? ) how many students pour on the coals after their successful landing. At which point, I close the throttle and gently ask: "Would you take off at night with the electrical system inop?"

One poor bugger got an unexpected first-night-flight treat. A (real) engine failure after takeoff, at 600 feet - just as we entered the crosswind turn. The outcome was just like we had briefed it. Another story, for another day.

Posted by: YARS (Tom Yarsley) | November 29, 2018 6:05 AM    Report this comment

You are absolutely correct, Tom

I just got back to FL after being up north for the summer. When I pulled my near new low mileage truck out to reposition it, it died and wouldn't start. Its never done that before and it blind sided me.. After a while it did so I blew it off. Driving it the next day, it started dying while I was driving, it wouldn't restart but then would ... so I had to limp it to the dealer with five stops enroute. I was told the ECU got "stupid" and had to be reflashed That cost me $175 ! What kind of software designer would make a perfectly good vehicle die while it was moving? There ought to be a fail safe mode. And all of that so that all those onboard systems can do stuff I don't really care about because some bureaucrat with an agenda dictated it ?

Moving back to the Airbuses or Max8, same story only MORE serious. How can you hand fly an airplane that won't let you cross control it into the wind? Worse, if a computer (read MCAS) won't let you do the same thing unless you snap your fingers, pull your ear and wink first. Geezola !! I'd love to have an airplane with one of those 912iS engines but now ... I'm not so sure. There ought to be one big red button in the cockpit. Let's call it the "holler uncle" button. You push it and you have to then do everything manually in some sort of fail safe mode. At that point, you pull back on the stick to make the houses get smaller. The Lion Air crash is a perfect example. KISS and if you can't ... at least tell me how all that magic works.

Posted by: Larry Stencel | November 29, 2018 6:05 AM    Report this comment

I enjoyed the article by "One of the Pauls" I was lucky enough to have a couple of instructors who considered partial panel as having only the oil pressure gauge for reference.

Now how about an article by "Both of the Pauls"?

Posted by: Richard Montague | November 29, 2018 7:06 AM    Report this comment

Paul? It sounds more like John..or maybe Ringo. I dunno, but it's a familiar tune in any event.

Posted by: phil delong | November 29, 2018 7:31 AM    Report this comment

"What kind of software designer would make a perfectly good vehicle die while it was moving? There ought to be a fail safe mode."

You didn't mention which truck you got, but in my car I know there is a fail-safe mode. I had an issue where the electronic throttle position sensor disagreed with the commanded position, so the ECU would go into fail-safe mode where it would idle the engine regardless of throttle pedal position. That's better than it potentially going to WOT uncommanded (and it's a sports car, so that would be a bad thing). But the engine did still run, so I had power steering and brakes and could control the car. Fortunately, turning the engine off and back on again would reset things and I could continue to drive. I eventually replaced the electronic throttle and the problem went away. In my mind, it did exactly what I would want it to do. And if it was all mechanical (no electronics), I would either have to give up performance for the same mileage, or give up mileage for the same performance.

As for the flying, I've never tried covering up the ASI and flying without it, but I suspect I would be able to pull it off. I did have a bad VSI once during IMC, though. Oddly, the altimeter and ASI appeared to be working, but I still decided to ignore those and go by the power setting and pitch attitude while I troubleshooted the issue (i.e. switched to alternate static air). It was mostly a non-issue, and involved the same method of control that would be used if it was a faulty ASI.

I think regardless of what the problem is, everything comes down to knowing the aircraft systems and possible failure modes, and how to fly using very basic power/pitch combinations (i.e. "seat of the pants" flying).

Posted by: Gary Baluha | November 29, 2018 8:21 AM    Report this comment

Your old-school airline pilot correspondents apparently haven't been reading the published information about the Lion Air accident. The problem wasn't the unreliable ASI.

The leading theory of the accident is that the aircraft had what amounts to a runaway stabilizer, as a result of a faulty AOA reading that led to the aircraft automatically trying to trim nose down. Since the AOA reading was faulty, actually being nose down did not stop the trim motor.

Here's what your correspondents evidently missed: on the 737MAX, no, you cannot "just grab the controls and actually fly the thing". On the 737NG, maybe. But not on the MAX: the stabilizer is more powerful than the pilot. Yoke, rudder and throttle won't save you.

I read these "I can't believe someone would crash a perfectly good airliner when they have a system problem - I can fly my Piper Cub with no instruments at all!" articles, and I recall a conversation I once had with a hang glider pilot who was planning to buy an ultralight sailplane. In his mind, he could fly a hang glider, and you can fly an ultralight sailplane under Part 103, so it's just another hang glider, right?

No, I said, it's not. It's a sailplane. In a hang glider, at full nose-down you'll top out at 60 mph and nothing bad will happen. In this sailplane, you can shoot through VNE in under three seconds and you may not be able to recover. In the hang glider, at full speed, if you pitch up or hit a punchy thermal, it will be exciting, but nothing really bad is likely to happen. In the sailplane, well above VNE, you may lose the wings. In a hang glider, you just fly your approach "fast-ish" and that's fine; in the sailplane, if you do that you'll float all the way to the end of the landing area without touching down - so use the airspeed indicator to set your approach speed.

The good news: after he recovered from the crash, he got pretty good with an ultralight sailplane.

No, just because you can do it in a Cub or a Cherokee or a hang glider doesn't mean anyone could do it in any airplane. I have about an hour in a Piper Cub. Easiest-to-fly airplane EVER (admittedly, on a grass strip, no wind). I did things in that airplane I have never done and will probably never do in any other airplane. I looked - and felt - like an ace! Certainly, flying from the back seat with an instructor in the front meant no ASI, from the get-go.

But I'm not fooled by my brilliance in a Cub. Low-drag airplanes are different. Highly-loaded wings are different. Swept wings are different. Jets are different. A 737 is not a Cub.

The Lion Air crew appear to have had big-airplane problems.

Posted by: Thomas Boyle | November 29, 2018 9:12 AM    Report this comment

"Which Paul"?

In the first sentence, the word "illuminati" made me think it was Bertorelli--one of the things I like about his writing is his reference to words and ideas not commonly used by the "10th grader" that writers are cautioned to use as their target audience.

As the article progressed, however, I believe it to be Berge--references to everyday metaphors like "swiss cheese"--references to military flight training experiences--and MANY references to how to instruct.

At Oshkosh, I once told Bertorelli that I enjoyed his insouciant style of writing. He replied "Insouciant? Where I come from, that's a big-***** word!"--the rejoinder was insouciance itself! BOTH Pauls pepper their columns with bon mots and descriptive verbal illustrations of their point--without wandering TOO FAR afield.

And that's why they are our favorite aviation authors!

Posted by: jim hanson | November 29, 2018 9:48 AM    Report this comment

To the two Paul's...an outstanding article. I believe they collaborated and we got the best of both of them. I lift my glass in a toast to unusual but entertaining metaphors to explain a street-wise, common sense approach to outside the cockpit, good old fashion, attitude flying.

Regarding the Lion Air crash and Bonanzas, the VNE on my D35 is 203mph. The early Bonanzas have a drag coefficient almost identical to a P-51. Through the ultimate stress analysis of certifying an early Bonanza in the utility category, it had to demonstrate the tail would stay on through 286mph. Beech learned that it took just 6 seconds in a 30 degree dive to accelerate from VNE of 203 mph to 286mph at cruise RPM. it doesn't take long to let a Bonanza get away from you. A 737 MAX is cleaner than a 70 year old Bonanza and weighs a bit more than my 2725lb gross weight. With pitch excursions every 5 seconds, one can surmise how rapidly out of control that Lion Air flight progressed. Like previous folks have expressed, a 737 MAX is no Cub.

Posted by: Jim Holdeman | November 29, 2018 10:44 AM    Report this comment

"Here's what your correspondents evidently missed: on the 737MAX, no, you cannot "just grab the controls and actually fly the thing"

They didn't miss this at all, Thomas. We don't have enough information to know what else was going on in the cockpit, but pointing out here that once a runaway trim condition is recognized and both stab trim cutouts are employed, the airplane can be hand trimmed and hand flown, as the previous crew did with the same set of conditions. The trick is to recognize the condition. Also unknown is if other mechanical failures could have been involved that were not for the previous crew.

Posted by: Paul Bertorelli | November 29, 2018 10:46 AM    Report this comment

I have BAD news for everyone ... Paul Berge (aka 'Id Est') is a pseudonym that PB uses. It's the same person. He can write two different ways ... kinda like people who speak two languages. :-)

Gary B: Near new GMC. It was throwing so many different DIC messages that I couldn't figure out what was happening. All I knew is that it would suddenly die. I anticipated that it might do that while driving it so I purposely stayed on the R side of the road to be able to roll off ... and did several times. I didn't have PS or PB so I had to manhandle it ... like Lion Air. Because the ECU s/w was corrupted, it allowed it to die yet it'd start up fine after a minute or so?? I don't believe it was an ECU input issue; I agree with the mech ... it was the ECU. In the hands of a lesser driver, a crash could have occurred (sound of me patting myself on back). Oh for the days of my first car ... a '53 Chevy stove bolt six with a sofa for a back seat (read between the lines - hint, drive ins). When the first EMP hits, only '53 Chevy's will be usable.

Tom B: The blog is just talking about Lion Air and then digressing to losing the ASI. I took away from all the reading that the prior crew MAY have successfully flown the airplane with the trim switches turned off to bypass the MCAS system but didn't communicate this?? What this DOES show is that you need to understand ALL the subtleties of each airplane you fly. Some of them are insidious. Now toss in that they weren't even aware of that system and ...

Speaking of ASI loss ... this happened to me a couple of years ago (pitot tubing failure). I never flinched. I've flown the airplane so many hours and years that I know what it feels and sounds like. Besides, most folks have SO many GPS sources in the airplane that GPS ground speed +/- wind ought to give you an idea of what's happening as a backup.

Yars won't like this but ... I believe this points out that there will never be an autonomous airliner. One pilot with a backup crew who can maybe step in but never autonomous. NOW I've started it

Posted by: Larry Stencel | November 29, 2018 12:34 PM    Report this comment

Being older than dirt, almost, I was taught "pitch plus power equals performance." It works.

On a dark and stormy night in 1982 while the FAA was rebuilding from the controllers' strike, I lost my airspeed indicator in a Seneca over Saint Louis as the pitot heat failed in icing conditions. Not knowing what other deicing equipment was failing, though the boots and ice lights were working, and seeing that DuPage, our destination, was closed, we decided to land. Saint Louis was calling something like 500 and 2 miles, so it was an easy ILS. With gear down and 15 inches or so of manifold pressure (works in essentially any piston airplane), we negotiated the ILS with minimal fuss. I knew the pitch for an ILS, I knew the power settings for an ILS. Yes, I told ATC we had a problem, but I sure didn't sweat the details. It was a simple form of partial power.

Today, however, I see a lot of people who get really uptight thinking about that failure while in severe clear VFR during the daytime. They have forgotten the basic equation.

Posted by: Jeff Williams | November 29, 2018 12:50 PM    Report this comment

Jeff, it's not that they have "forgotten the basic equation," they don't even know.

Posted by: Tom Cooke | November 29, 2018 1:49 PM    Report this comment

"Yars won't like this but ... I believe this points out that there will never be an autonomous airliner. One pilot with a backup crew who can maybe step in but never autonomous."

Oy. I guess I DO need to write that guest blog... For now, let me say simply that a properly-designed autonomous flight control system would have almost nothing in common with any "autopilot," nor with any of the myriad "helpful" little gnomes like Boeing's MCAS. The design paradigm is quite the opposite.

Posted by: YARS (Tom Yarsley) | November 29, 2018 2:18 PM    Report this comment

I KNEW I could reel you in, Yars. That didn't take two hours. :-) When the first fully autonomous airliner enters major carrier revenue service, I will buy you a nice big steak dinner. If it doesn't happen in 20 years ... you owe ME a steak dinner.

Get ta writin' ... you can do it.

I have bad news for ya'll. Doing research this afternoon, I have discovered a psychosis known as Writer's Bipolar Disorder (WBD). When writers who use pseudonyms lose control over who is doing the writing, the disease has entered the terminal phase. Sadly, at that point it is incurable. Medications and therapy have been shown to help.. There's even a test for it ... manifestation of extremely creative writing followed by loss of identity. Methinks we need to start a blogfunding site here to help pay for Paul's identity crisis. Look at who signed off on this blog. I only have one question ... WHO gets the money?

And it ain't even April Fool's day yet.

Posted by: Larry Stencel | November 29, 2018 2:48 PM    Report this comment

...then a foreboding Paul spread over the room... ;-)

Posted by: YARS (Tom Yarsley) | November 29, 2018 3:16 PM    Report this comment

Beginning to appreciate Paul B's good and talented writings.

Posted by: Rafael Sierra | November 30, 2018 1:49 AM    Report this comment

Every spring when doing our first of season recurrency and mutual checkouts for our glider instructors, we inflict no ASI, no altimeter approaches and landings on each other. If the flight is going particularly well or if the instructor is particularly mean, the check pilot may "freeze" the spoilers as well so the pilot must then land using a slip or cut corners in the pattern to hit the touchdown spot.

Posted by: Pete Brown | November 30, 2018 9:11 AM    Report this comment

Well, I'll have get out my old trusty "sardonic meter" and take some careful measurements to determine which PB wrote this essay (hint: Bertorelli often pegs the meter in a most delightful way).

The only ASI failure I ever experienced was when the pitot flap cover stuck closed on our PA-22 (you remember the little vane-operated pitot covers that look like the exhaust flap covers on a John Deere tractor?). While its a little disconcerting to see 0 mph on the ASI during climbout, you quickly settle into "fly the plane mode" and ignore it. Turns out the natural whistling of the slipstream is just about as good as the ASI anyway. If Orville didn't need one, why should I? :-)

Posted by: A Richie | November 30, 2018 9:18 AM    Report this comment

Jim Hanson, as Ma Kettle once said, "I'm surprised at your learnin'," Ya guessed wrong. :)

Posted by: Paul Bertorelli | November 30, 2018 10:06 AM    Report this comment

Just a brief note - I too learned to fly at Ft. Bragg - started in a J-3 at Brown Field on Smoke Bomb Hill and stayed with them through my high school years at Simmons AAF.

Just pleased to hear from another from the "old days."

Posted by: George Burdell | December 2, 2018 6:13 AM    Report this comment

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