Plane collision at Aberdeen Airport
It doesn't appear that there was an engine run taking place, although there was clearly an engineer in the cockpit for some reason (who wisely abandoned ship when it clearly wasn't going to stop).
The METAR showed a light south-easterly surface wind, so that wouldn't have been a factor. But there is a discernable slope (downwards west to east) in the terrain between the Bristow apron on the western edge of the airport and the passenger terminal, so good old gravity may have played a part.
de minimus non curat lex
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Tell me I'm not the only one hearing the Benny Hill chase music when I watch that (somewhat sped up) video .
I guess I didn't know my speakers were off, because on re-viewing it actually does..
I guess I didn't know my speakers were off, because on re-viewing it actually does..
Last edited by Mad (Flt) Scientist; 20th Jun 2020 at 13:17.
It will come out in the wash. It was on a remote stand as as David has pointed out where a tug would not be required to see off the aircraft. One doesn't push to manouver a 20 tonne airframe unless as a last resort. Chocks should only be removed when the aircraft is ready to be moved or for engineering reasons as aircraft jacking for a wheel change or a maintenance proceedure. Here ends the CRM / HF lesson for today.
Loads of us that are furloughed will have to get back in the zone that was very likely with those that were in the video. Currency for a lot of us that are professional fight crew, CC , Engineers and others has been serverly degraded in the last few months. Going back to work needs us to think and remind ourselves that we are not current.
Last edited by Cat Techie; 20th Jun 2020 at 20:41.
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Thread drift... when I worked for deHavilland in the early '80's, Dash 8 number one, C-GDNK (named for DH Director Donald Kendal) was painted for its roll out. As with airplane things, there was a bit of a rush at the last minute, so we were there Sunday evening just after the final coat of paint went on. I was just hanging around, I had no actual role in preparing the plane for display. It was determined that the tug which had pulled the plane into the paint shop, could not easily be positioned back to push it out. So six of us, and one elderly painter carrying a set of chocks, pushed it out. Four of us each took a main wheel, and two more pushed on the main gear legs, as there was no other place to push on - new, and not cured paint. We couldn't quite get it over the hump of the hangar door tracks, but by then, the tug could be positioned to finish the job.
But yes, rolling any plane by hand, with no plan to stop it is a bad idea. And placing the chock under a wheel in motion is certainly hazardous!
But yes, rolling any plane by hand, with no plan to stop it is a bad idea. And placing the chock under a wheel in motion is certainly hazardous!
I also checked across pad 31 and the slope is about the same all the way across but by then I had done the screenshot.
My question is why the individual who was on the aircraft didn't jump into a seat and apply the brakes?
if the accumulator was depressurised, the brakes would not operate until the engines were turning, or the accumulator was recharged with a ground hydraulic rig.
Would be interesting to know when the chocks were removed and by who, or was it parked up without them and these guys set things in motion..The video will hopefully have the evidence for that.
The airport authority have everything they need to investigate. I am not rated on the Q400 and while I know the likes of a Jetstream 41 has no standby electro pump, am surprised the Q400 has not. Then again my other ratings are regionals where standby hydraulic power is highly desirable or essential.
Thread drift... when I worked for deHavilland in the early '80's, Dash 8 number one, C-GDNK (named for DH Director Donald Kendal) was painted for its roll out. As with airplane things, there was a bit of a rush at the last minute, so we were there Sunday evening just after the final coat of paint went on. I was just hanging around, I had no actual role in preparing the plane for display. It was determined that the tug which had pulled the plane into the paint shop, could not easily be positioned back to push it out. So six of us, and one elderly painter carrying a set of chocks, pushed it out. Four of us each took a main wheel, and two more pushed on the main gear legs, as there was no other place to push on - new, and not cured paint. We couldn't quite get it over the hump of the hangar door tracks, but by then, the tug could be positioned to finish the job.
But yes, rolling any plane by hand, with no plan to stop it is a bad idea. And placing the chock under a wheel in motion is certainly hazardous!
But yes, rolling any plane by hand, with no plan to stop it is a bad idea. And placing the chock under a wheel in motion is certainly hazardous!
Last edited by Cat Techie; 20th Jun 2020 at 20:38.
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Given that both the rudder and steering, (along with the brakes) require hydraulic pressure to operate it wouldn't have made any difference.
Might as well be a spectator outside as be one inside.
Might as well be a spectator outside as be one inside.
The Q400 has a hand pump in the right landing gear bay to pump up the brake accumulator. Nothing could be done in the cockpit once the aircraft started to move.
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The parking brake is on the No2 system, with a nitrogen charged accumulator located in the right wing root. According to most SOPs, minimum pressure in the No2 system before engine start is 500psi, anything below that then the system pressure must be restored by operating the manual pump in the right engine nacelle. That is why it is normal to start the No2 engine first on the Q400. The hydraulic pumps are driven of the reduction gearbox, the APU supplies DC power and Air only. The reason most SOPs use 500psi as minimum pressure (or 1000psi if you choose to start the No1 engine first) is because it is possible to have indications of pressure in the No2 system below 500psi but that is most likely residual accumulator gas pressure, and brakes will not function. So it is quite easy to foresee a scenario where an aircraft parked on an incline with little or no accumulator pressure will begin to roll when the chocks are removed or someone cycles the parking brake to test it and unwittingly depleting the remaining pressure.