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So I'm at airport dealing with a locker at my tiedown whose combination lock was frozen solid and would not open. There is a 172 with its engine running about 50 feet behind me in its tiedown. It had been recently started and the pilot was doing his pre-taxi checks.

While I had my back to the aircraft I suddenly heard a sound like an extremely loud backfire followed by silence. At first I thought that ir was the loudest backfire I ever heard, but the silence was alarming. I spun around to see that the 172 had rolled forward into a parked Cherokee that was across the taxiway. The 172's propeller at idle RPM managed to take off all of the leading edge outboard of the fuel tank to the wingtip all the way back the spar. In an instant it pulled out all the rivets, warped the wing, and tore the skin apart. It also sent pieces of fiberglass, plastic and metal all over the ramp.

Fortunately the pilot was not hurt, though he was in shock for a few minutes. A flight school lost 2 aircraft in a moment of lost focus. I was stunned to see how much energy that spinning prop has at idle RPM!

Thanks for the inside, Oracle427. Cessnas are infamous for their poor parking brake grip and the aircraft is likely to drift if the pilot loses focus. At my local airport, we have a dozen of C152s and as many C172s, and I have flown almost every of them at least once. And on almost all of them the parking brake won't hold for long. This made me take a habit of keeping my feet depressing the brake pedals always while I am supposed to stand still on the ground in a Cessna.

There was an infamous case close to here where a pilot reportedly attempted to throw start a Cessna, model 152 I think. Or actually succeeded. The plane was apparently at modestly high power, the parking brake was either not set, or not properly set, and of course there was no one in the cockpit. Nor any wheel chocks apparently. The plane went off through the apron fence, luckily not hitting much anything - or anyone - else. I believe the aircraft was scratched off. Pilot escaped with no injuries I understand.

-Esa

ilya1502 wrote:Thanks for the inside, Oracle427. Cessnas are infamous for their poor parking brake grip and the aircraft is likely to drift if the pilot loses focus. At my local airport, we have a dozen of C152s and as many C172s, and I have flown almost every of them at least once. And on almost all of them the parking brake won't hold for long. This made me take a habit of keeping my feet depressing the brake pedals always while I am supposed to stand still on the ground in a Cessna.

As an instructor I always had a rule about parking brakes. I treated them myself as being non- existent on the aircraft. I can't remember a single time in all the years I was active as a pilot when I used a parking brake. My rule and what I taught every student I trained to fly was simple. Anytime an engine was running a parking brake should NOT be in use.
Parking brakes are about the most unreliable system ever invented to be put in an airplane. They slip, in the winter they freeze "ON" and are generally useless.
Using them during mag checks I consider a prime way to allow forward movement of the aircraft while your head is otherwise occupied looking at the panel. Also, you can't "feel" the brakes fail if your feet are off the pedals.
On mag checks I STRONGLY suggest to pilots they not use parking brakes. For example, in a situation where more than one aircraft is warming up in the run up area at the end of a runway, aircraft can be sitting fairly close to one another. If the plane in back of another plane does a run up using a parking brake and the brake fails to hold, there could be a serious incident. Had the pilot in back been holding the brakes with the pedals, the forward movement of the plane might have been detected and controlled.
If you are beginning to get the picture that I don't like parking brakes, my time here hasn't been wasted. LOL
Dudley Henriques

Uploaded a picture. It was a CHerokee 140 that was struck. It looked like a 172P 160HP that hit it. From a distance you may not notice any damage on the 172, but the prop is bent outwards at the tip and has some good gouges in the leading edge and camber face.

Oracle427 wrote:Uploaded a picture. It was a CHerokee 140 that was struck. It looked like a 172P 160HP that hit it. From a distance you may not notice any damage on the 172, but the prop is bent outwards at the tip and has some good gouges in the leading edge and camber face.

Looks bad. Thankfully no human damage this time.
DH

My father in law was telling me a story a couple months ago of a C-45 that he's going to be repairing. Another pilot couldn't get his starter to engage so he got out of the plane, moved the prop to reach through the cowl and tap the starter, but he left the mags on and it started when he moved the prop. I don't think he got hurt but there was substantial damage to his plane and the C-45 it ran into.

I remember when two Yak-18T at my flight school were ruined in a similar way, but due to a faulty pilot, not the parking brake. In Yak-18T, brakes are pneumatic, and the only directional control during taxi is via differential braking — the nosewheel is free-castering. And to operate the pneumatic brakes you have to open the pneumatic valve which allows the air pressure from the main reservoir to the system. But here is the thing: the engine starter is also pneumatic, so one may think it's impossible to miss the valve, however it is not the case as residual pressure in the system might be enough to crank the engine. And the POH of Yak-18T prescribes to set the throttle to about 1/3 (that's not 1/3 inch, but 33% of throttle travel!) for starting... So you can imagine what happened: they neglected the checklist and forgot about the valve. As soon as the engine roared the airplane yanked forward, but they were unable to either stop the aircraft or at least turn it away. Luckily, no human casualties, but two ruined airplanes.

What ever happened to the aircraft in this story? I hope they didn't end up in the beer can factory.

Both aircraft are being fixed. As of last week both engines were still off and being repaired. The damaged wing still is damaged, I guess they'll fix that eventually. Both engines were damaged as the prop on the parked plane was vertical and the tip was struck by the high wing.

ilya1502 wrote:Thanks for the inside, Oracle427. Cessnas are infamous for their poor parking brake grip and the aircraft is likely to drift if the pilot loses focus. At my local airport, we have a dozen of C152s and as many C172s, and I have flown almost every of them at least once. And on almost all of them the parking brake won't hold for long. This made me take a habit of keeping my feet depressing the brake pedals always while I am supposed to stand still on the ground in a Cessna.

In all the years I instructed and flew, and that included 72 different types of airplanes, I never once have used the parking brake on an airplane. They are notorious for being a failure waiting to happen. I treat them as being non-existent in the aircraft.
There is no produced evidence in this incident that a parking brake was involved although all the classic signs of this are evident.
Dudley Henriques

Here is what I learned about the incident.

The poor was trying to call grind to get a taxi clearance, but getting no response. They checked the radios with no luck. They then decided to check the headset jacks.

In order to look at the jacks, they had to move their seat and their feet off the toe brakes. They set the parking brake to do so, got their head down looking at the connections and within ten seconds, it was all over.

Man that is bad luck. I know of an incident in which a C182T was parked on a hilly airport with the parking brake set and then rolled backwards down the hill and hit a hangar with the tail. The pilots had to watch this in horror as they were drinking their coffee on the terrace. Must be an aweful feeling.

What I take from all this is exactly what Dudley said. Don’t use the parking brake as such or if you must make sure it is holding!

Happy flying

Piper_EEWL wrote:Man that is bad luck. I know of an incident in which a C182T was parked on a hilly airport with the parking brake set and then rolled backwards down the hill and hit a hangar with the tail. The pilots had to watch this in horror as they were drinking their coffee on the terrace. Must be an aweful feeling.

What I take from all this is exactly what Dudley said. Don’t use the parking brake as such or if you must make sure it is holding!

Happy flying

Possible post accident analysis involving a parking brake might reveal that especially during engine runup, if holding a plane with a parking brake while the head in down below the glare shield on the gauges, it can be hard to "feel" any parking brake failure. The aircraft could in theory travel some distance forward before movement was discovered.
This was why I never used them and have never recommended using them.
Dudley Henriques

DHenriquesA2A wrote: Possible post accident analysis involving a parking brake might reveal that especially during engine runup, if holding a plane with a parking brake while the head in down below the glare shield on the gauges, it can be hard to "feel" any parking brake failure. The aircraft could in theory travel some distance forward before movement was discovered.
This was why I never used them and have never recommended using them.
Dudley Henriques

Yes that’s very true. Especially on a hard surface airport the plane would just run off without the parking brake during the run up. I’ll keep that one in mind!

Happy flying