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FLYING LESSONSFLYING LESSONS for December 19, 2013 suggested by this week’s aircraft mishap reports FLYING LESSONS uses the past week’s mishap reports to consider what might have contributed to accidents, so you can make better decisions if you face similar circumstances. In almost all cases design characteristics of a specific make and model airplane have little direct bearing on the possible causes of aircraft accidents, so apply these FLYING LESSONS to any airplane you fly. Verify all technical information before applying it to your aircraft or operation, with manufacturers’ data and recommendations taking precedence. You are pilot in command, and are ultimately responsible for the decisions you make.

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This week’s lessons: I was flying a Beechcraft A36 Bonanza home from Thanksgiving with my wife and our son aboard. Somewhere over Indiana the Bonanza’s attitude indicator (AI) began to tumble.

The indications began slowly, but very soon the “artificial horizon” (to use the archaic term) was pitching up and down in very distracting oscillations.

Click on the photo or the link below to see video of the failure indications.

See www.youtube.com/watch?v=SRwuiQ9Yus0

I immediately knew something was wrong, however, because the airplane’s KFC225 autopilot—which references the AI—disconnected as soon as the instrument’s gyroscope lost stabilization. Although the Flight Director command bars remained elevated (making it look like the autopilot might still be operating), the autopilot disconnected. The AP annunciator extinguished and the Autopilot Disconnect horn chirped.

The airplane was trimmed for level flight before the AI failed, so it was still trimmed after—any loss of control would have been entirely my fault. All I had to do was to keep from making gross control inputs and the airplane’s natural pitch and yaw stability would keep me upright and straight. The Bonanza is neutrally to slightly negatively stable in roll, so it was important to keep the wings level. I did so by holding heading with rudder instead of trying to make small corrections with the yoke—this made my inputs less likely to impact all three axes of flight, and the Beechcraft aileron/rudder interconnect tended to coordinate small rudder pressure inputs as well.

Four things were going for me (and my passengers): 1. I was in visual meteorological conditions (VMC). Attitude control meant looking outside

the airplane.

2. I regularly practice partial panel flight (flight by reference to some, but not all of the basic instruments). This keeps my scan sharp, and probably at least as importantly, emphasizes the need for very light, very small inputs on the controls in partial panel flight.

3. The A36’s heading indicator is electric, not air-driven. It continued to work, making identification of the failed instrument easier and partial panel control much less challenging.

4. The autopilot disconnect told me immediately that the gyro had failed—or at least that something had changed and I needed to find out what it was.

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A quick scan at the usual suspect, the gyroscope’s air source (an instrument air pump in the case of this A36, a vacuum pump in most light airplanes), revealed indications of normal air pressure. The late-model Bonanza’s INSTR AIR light was not illuminated. It appeared the gyroscope itself had failed, not the source that drives it.

Regardless, and even though I was virtually certain it would make no difference, I activated the airplane’s standby instrument air pump. The STBY AIR annunciator lit up, and the instrument air gauge showed a very slight uptick in pressure—both expected indications. Also as expected, nothing changed with the AI. The wild gyro oscillations, as seen in the video, continued. I turned off the back-up air pump.

That’s easy to fix. I always fly with a stack of “sticky notes” handy for a number of purposes. One is to quickly cover up a failed instrument. Look again at the video, then see this picture (right) to see how much easier it is to fly “partial panel” without the distraction of the gyrating gyro. See www.youtube.com/watch?v=SRwuiQ9Yus0

CAUTION: I don’t use the standard “soap dish”-style instrument covers. One of my former supervisors found out the hard way that the glass in the face of some AIs is thin enough that a good push to stick on the “soap dish” can break the instrument glass. The Federal Air Regulations required a report to Air Traffic Control and terminating flight when it was no longer equipped for the type of flight operation (in this case, IFR). The airplane’s Limitations also require a functioning AI for IFR flight. Luckily, I was in very clear skies and flying directly toward the center of a dry high pressure system. I called up the satellite imagery on my Garmin 796 hand-held and confirmed there wasn’t a cloud in the sky between my position and home. I continued the trip home VFR.

Not working in our favor: the airplane did not have a back-up attitude indicator and the attitude-based autopilot was functionally unable to re-engage. In a real pinch I could have called up a synthetic vision presentation on the 796, at least for basic attitudinal orientation.

An FAA/AOPA report tells us we don’t do all that well at identifying failed instruments, or flying by reference to a partial panel after an instrument quits. See www.thomaspturner.net/FAA%20Partial%20Panel%20Performance%20Study.pdf

There is no checklist for “attitude indicator failure” in the A36’s Pilot’s Operating Handbook. It’s unlikely one exists in the handbook for the airplane you’re flying. This is one of those things we’re expected to consider ahead of time to develop a course of action. Your personalized checklist might include, however:

1. Maintain control of the airplane. Do not retrim unless you (or the autopilot) was retrimming at the time the failure occurred. Keep the trim set until you need to change it with a change in flight conditions. Use very light control inputs and limit use of the ailerons.

2. If you have an autopilot and it’s still working, use it. Right or wrong, we IFR pilots often pride ourselves on our ability to fly partial panel so much that we’re unwilling to do the one thing that will save our lives—turn on the autopilot. Don’t be a hero. Use it.

3. Identify the failed instrument. Crosscheck supporting instruments to determine which, if any, has/have failed.

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4. Confirm the failure. Check other indications, such as an instrument air pressure or vacuum gauge, or electrical indicators with electrical instruments. If you need more help to confirm, smoothly level the wings by reference to the attitude indicator. Then check the turn coordinator/turn and bank, and the heading indicator. If two indicators agree then it’s a good bet the third has failed.

5. Cover the failed instrument. Remove the distraction of a dead or wobbly indicator.

6. Use backups, if available. Activate backup instrument air or electrical sources. Switch your scan to backup instrumentation if you have it and it’s placed within your primary scan. Don’t forget “unofficial” aids, like GPS for heading and handhelds, even your iPad, for attitude.

7. Use known combinations of power, flaps and gear position, and as best as possible, pitch attitudes to cautiously control the airplane through the remainder of your flight. Aerodynamics don’t care what an attitude indicator or other failed instrument says—the aircraft will still respond predictably to changes in power, configuration and attitude.

8. If you’re in VMC, stay in VMC, even if that means going well out of your way to land.

9. If you’re in IMC, aim for VMC. Again, don’t be a hero. Aim for clear skies. For U.S. pilots, FAR 91.7 virtually requires it.

See www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=3efaad1b0a259d4e48f1150a34d1aa77&rgn=div5&view=text&node=14:2.0.1.3.10&idno=14#14:2.0.1.3.10.1.4.2 10. If you can’t remain in VMC, declare an emergency. Take any and all help you can get

to make a safe arrival at the nearest airport with above-minimum weather (the higher the better). Choose an approach with vertical guidance to help you fly your approach (this is much more common now with the proliferation of approach-certified GPS).

Before an instrument fails, prepare for your passengers’ (and your) survival: • Know how your instruments are powered, and how to operate the back-ups that exist in

the aircraft you’ll fly. See Section VII, Systems Description, of the POH if one exists for the aircraft.

• Know the requirements and failures modes of any autopilot on board, including which instruments are sensed for what autopilot modes and what autopilot degradation occurs with each type of instrument failure. Read the autopilot supplement to the POH.

• Know precisely the effect changes in power, flaps and (as applicable) landing gear position, and pitch attitude have on airspeed and rate of descent or climb. Commit these numbers to memory, and use them if your ability to monitor performance through the flight instruments is degraded.

• Faithfully conduct the Before Takeoff operational checks of your flight instruments, and terminate flight before it starts if an instrument doesn’t pass inspection.

• Regularly practice partial panel flight with a safety pilot or flight instructor. The cost of an hour of instruction every six months or so is much less than the expense of adding back-up instrumentation to an airplane, and may be worth much more in an emergency. It may be your only option if you are not sole owner of the airplane(s) you fly.

• Keep sticky notes or some other instrument cover immediately at hand, to cover up a distracting failed instrument or instruments.

Surviving instrument failure in flight, especially at night and/or in instrument meteorological conditions (IMC), is a matter of being ready for the event before it happens—not waiting until the failure occurs to see how good you are. Comments? Mastery.flight.training@cox.net

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Debrief: Readers write about recent FLYING LESSONS: FLYING LESSONS cheerleader (I mean that in a good way) Bill Caton writes:

Another great issue!! I particularly like the last section on go/no go decisions. To me, this is the most stressful part of flying. Susan and I are flying to Palm Springs 12/31 with a stopover in Phoenix Goodyear airport for the Baylor Fiesta Bowl game. Tickets and hotel have been purchased. I started thinking weather a day or so ago and how unpredictable it is this time of year. Fortunately we will be travelling to a part of the country where better weather is more consistent. This article is a great reminder that no risk is worth it for a game. The game is the only thing with a hard deadline.

I hope it all comes together for you and Susan, Bill. Yes, we’ll be exploring ways to stack the deck as much as possible toward “go” with preflight planning and preparation, in upcoming editions of FLYING LESSONS Weekly.

Reader Ed Bodkin chimes in:

Tom, I have been flying for 45 years. USMC, American Airlines, and now a Baron 58. I like your approach to flying... Common Sense! Belly Barometer. This is a business fraught with rules, nuances etc., most of which I can’t remember. If it feels bad, appears to be stupid, it probably is! Keep up the good work.

Thanks, Ed! We’ll get to more Debrief items next time.

“Great investment, Tom! Thanks for all you do!!”—Don Bowles

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Thank you, generous supporters

Merry Christmas to all who observe, and happy holidays and best wishes for a new year filled with enjoyable and safe flying to all. Thanks very much for your Debrief comments, your kind words and your support each week, both moral and financial. It makes doing this worth it.—tt

Share safer skies. Forward FLYING LESSONS to a friend.

Personal Aviation: Freedom. Choices. Responsibility. Thomas P. Turner, M.S. Aviation Safety, MCFI 2010 National FAA Safety Team Representative of the Year 2008 FAA Central Region CFI of the Year

FLYING LESSONS is ©2013 Mastery Flight Training, Inc. Copyright holder provides permission for FLYING LESSONS to be posted on FAASafety.gov. For more information see www.mastery-flight-training.com, or contact mastery.flight.training@cox.net or your FAASTeam representative.