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I have heard of pilots rolling airplanes that aren't approved for it (Cessna 172, Learjets, etc.), and other than the obvious legal issues, are there any mechanical or safety reasons to avoid it?

DISCLAIMER
I do not advocate doing anything (like this) that is not legal, but am looking more for additional reasons that I can use to dissuade people from doing this when they say that it isn't hurting anyone or something along those lines.

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2 Answers

up vote 22 down vote accepted

There are a lot of good reasons not to roll such an airplane.

  1. If the plane has gyroscopic instruments, you might tumble them (cause the spinning gyro to hit the inside of the instrument). This can be expensive.

  2. You might easily over-stress the air frame. Normal category light aircraft are rated to -1.5 to +3.8Gs. (That's for a new aircraft) A botched roll can easily hit 4.5 or higher.

    If you over stress the air frame, you might just put a lot of very expensive "wrinkles" in the skin that would be very hard to explain to the FBO, your boss, or the insurance company. Trashing the gyros would be cheaper.

    If you're not lucky, the wings fold up and you fall out of the sky. It's a stupid way to die.

  3. Non-aerobatic aircraft typically have limited elevator authority; once upside down, you might find it very difficult to keep the nose pushed up high enough to keep the roll going. Turning a botched roll into a "split-S" is one of the worst "recovery" mistakes you can make, and you're setting yourself up for it.

  4. Non-aerobatic aircraft often have gravity-feed fuel systems. A little bit of 0 or negative "G" and it will get very very quiet in the plane. Some people consider this silence detrimental to the continued safety of the flight.

  5. Non-aerobatic aircraft rarely have inverted oil systems. As the engine gets quiet, it also loses most of its lubrication. Bare metal on metal friction can be detrimental to achieving TBO.

Having said all that, in the hands of an expert, it is technically possible to barrel roll most aircraft.

A good way to tell if you're an expert is to call your insurance company and tell them exactly what you plan to do. If they'll quote you affordable coverage, you might be an expert.

Obligatory links because if I don't include them someone else will:


If you want to roll an airplane, contact your local aerobatic club. In the US and some countries, it's the International Aerobatic Club. Get some competent dual instruction in a suitably rated airplane.

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I think it was a 707 that Tex Johnson rolled. It was done during a presentation of the plane, in front of the president of Boeing and an FAA representative. There were reporters on board, and one of them managed to get a photo out of the window when the plane was inverted. –  Edward Falk Dec 30 '13 at 22:36
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And as shown in the Bob Hoover video, a properly-executed barrel roll is a gentle positive-g maneuver all the way through. In theory, you could do this with any plane, as Tex Johnson demonstrated. In practice, don't do this unless you're Bob Hoover. –  Edward Falk Dec 30 '13 at 22:40
    
@EdwardFalk - you are correct, it was a 707. I've updated the answer. Thanks –  Dan Pichelman Dec 31 '13 at 20:06
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Do not even think about it unless you are an expert. I read about an incident in Sport Aviation in which a non-aerobatic performer rolled a piston twin. The airframe was overstressed and it broke up in flight. All four on board were killed.

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What if they are an expert aerobatic performer? –  Lnafziger Jan 12 at 23:18
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