Use caution taxiing behind big A/C on runup

[pelmet]

A good reminder that while it may be reasonable to taxi behind some turbine stuff if they are just holding in position, when they are doing a runup, be extremely cautious. A 150 got flipped over in Trenton quite a few years back. That one should have been obvious but an ATR can put out a good blast of air. Be paranoid. I flew some light fabric aircraft and was especially paranoid about prop wash and wake turbulence even from small helicopters on the ground and in flight.


A14C0014: The Millenium Aviation Cessna 150M, registration C-GCOT, was taxiing for a local training flight at Saskatoon, SK. The aircraft was taxied behind an ATR completing an engine runup. The instructor extimated the distance to be about 120 to 150 meters from the ATR. The prop wash from the ATR lifted the left wing of GCOT causing the right wing tip and propeller to strike the ground and sustain substantial damage. There were no injuries.

[AirFrame]

By the same token, it may be worth reminding larger operators to look out for smaller aircraft before firing up. A couple of years ago, clearing customs at KBLI, we pulled into the customs box that's painted on the ramp, about 100' from a RATHER large helicopter, that was parked, and had no people around it. As we got out to talk to the customs personnel and clear, the crew walked out to the helicopter and proceeded to start up. The customs staff was rather irate that we wouldn't leave our aircraft to go inside and clear customs, even when we pointed out the helicopter spooling up.

Adding stupidity to the situation was the customs officer who insisted that we could not move our aircraft out of the customs box until we had cleared customs, even though there was plenty of ramp space well away from the helicopter that we could have pushed to, then pushed back to the box later.

Pilot and passenger in each aircraft got on the upwind side and held onto the wingtip. The helicopter nearly picked us up with the aircraft as it lifted off... The customs officer who wouldn't leave us nearly sh*t himself when he realized what was happening. Helicopter pilot never clued in, or was just a complete *sshole, we never figured out which. He waved at us as he left. I think I waved something at him too.

[pelmet]

Good point, I had an RJ a couple of years ago park in such a way for de-icing that he was blowing jetblast where we were loading even at idle. I was worried about when he would power up to taxi out and the effect on our doors which have windspeed limitations. Glad we closed them.

And I had a captain turn around for parking in an area and damage a boat that was to be loaded on us.

Also had a Falcon 50 driver(from Magna I was told) many years back who used lots of breakaway thrust at an FBO that swung a PC-12 into a twin Cessna that I used to fly.

And so I dont leave myself out, I got an angry blast over a Unicom frequency many years back for doing a runup holding short of a runway pointed at a hangar with its doors open. Should have known better. I have tried to be very careful ever since for runups, startups and turning around in tight areas. Hopefully by the time you get some decent experience, you consider these things.

[JDW]

The same applies to large helicopters. I was waiting to take off out of buttonville a few years back when one of the ornge beasts was either arriving or departing not far from me. The yoke in my 172 snapped back so hard it couldve easily broken a few of my fingers. I doubt there was a risk of flipping us but it definitely got the heart going and under different circumstances couldve easily damaged control surfaces.

[Big Pistons Forever]

Also don't let ATC push you into crossing behind a large aircraft. YYJ , for example, is pretty bad for this as there is almost always a 737 or Q 400 mixed in with the light aircraft. All ground have to say is "Caution jet blast" and they are off the hook. It is ultimately up to you to decide if it is safe to proceed.

[looproll]

A Jetstream flipped over a C172 in Fort McMurray a few years ago.

[RatherBeFlying]

I was landing a Citabria while a Bell 47 was doing hover practice some 50 yards off the runway. Thought that was far enough away from a light helo, but the landing was interesting.

The other interesting landing was at YYZ past where a 747 was making a 135 degree turn to a taxiway. We were well above the top of the fin. but the air was definitely disturbed and we were quite happy not to have been lower.

[cgartly]

A 172 was flipped over here in Kelowna from propwash from a Convair doing a high power run about 2 years ago.

[TG]

Nice stories, at list some people or yourself are around to see what's going on.
If not, results are pretty obvious (flipped over?)

The worst situation: An aircraft being blasted without anybody realizing what's really happening.
You can get all kind of internal damage afterward that you won't see during a walk around.

http://www.flightglobal.com/news/articl ... in-319840/

Investigators have concluded that on-ground jet-blast contributed to the failure of elevator cables on the Air Moorea de Havilland Canada Twin Otter which crashed in French Polynesia last year.

France's Bureau d'Enquetes et d'Analyses had already determined that the Twin Otter crashed, killing all 20 occupants, after the pitch-up control cable failed shortly after departure from Moorea on 9 August 2007.

Outer strands on the cable had already suffered significant wear. But the BEA has also determined that several strands broke while the aircraft was on the ground, and believes that this on-ground failure was due to exposure to jet-blast.

It points out that the Twin Otter operated to Papeete, the airport on Tahiti served by Airbus A340s. By considering the airport layout the inquiry has constructed a theoretical scenario showing the blast from an A340 during start-up - even at a distance of 80m (260ft) behind - could have exposed the parked Twin Otter's empennage to exhaust velocities of 20-90kt.

I also know of a F406 crash in Uganda, total lost of elevator control after take off.
A day or so before, another aircraft was seen doing a power run blasting its tail from behind and more than probably damaging some cables or fairings.
It would have take a good inspection to find it, not a mere walk around without knowing what happened before.