Tuesday, June 23, 2020

Did nobody think about the weights and masses involved?


Last week an incident at Aberdeen airport in Scotland saw a DHC Dash 8 Q400 commuter airliner (empty and powered-down) roll unchecked across the hardstand, to run into an Embraer ERJ-145 parked on the other side.  Total damage to both jets is likely to run into the hundreds of thousands of dollars.

The incident was captured by a security camera. There's no sound in this footage.





I'm still shaking my head at the sight of ground workers trying to physically stop the airliner by pushing and pulling at it.  They must surely have been aware that, even empty, a Q400 weighs almost 20 US tons.  How, precisely, is human muscle alone supposed to stop that sort of mass once it's rolling?  What did they think they were going to achieve?

Verily, the mind doth boggle . . .




Peter

9 comments:

  1. While I'm sure that ground crew are not supposed to get in the plane, the damn stairs were down! Climb in, stomp on the pedals, turn the wheel to the right, something. But no, companies and our educational system train all of the brains out of people, and this happens.

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  2. Beat me to it. Rules are rules, you know.

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  3. Hey Peter;

    As a A&P type, the first thing I thought of was, ...why was the wheels not chocked....why was nobody riding brakes.....and the last thing I thought was....oh well...get ready to pee into a cup...

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  4. I watched a guy get off a heavy (#25k?) mule used to move the big aircraft, he parked it on the slight incline going down to the hanger doors and was walking down to the hanger and the mule started to roll.
    He got in front of it to try to stop it, not for long then he got out of the way.
    It rolled down & hit the nose doc hanger doors with a big bang. There was a huge bang when the two big doors fell and landed on the mule! People showed up from inside all around to see what caused that noise.
    He said he turned about and it was moving, he did what he could then he got out of the way. It was something to see...
    This was on an Air Force base (we were Coast Guard) so there were a LOT of people interested in what happened! He had put the parking brake on before he got off so he was covered.
    You do what you can...

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  5. Actually, even with the weight of the plane, if he had caught it as it first started inching forward and put his foot under the front wheel it would have stopped it. Once it got significant forward motion it was too late to do anything except make a jump for the boarding ramp or just sit back and watch the chaos.

    There's that slightly split second, though, where he could have stopped it. Maybe would have hurt, but it could have been done, especially if he was wearing steel-toed boots. Operative phrase is 'could have.'

    I've seen a similar sized vehicle chocked by a cordless drill or heavy flashlight.

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  6. No wheel chocks these days? Progress, I suppose.

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  7. Someone can kiss their job goodbye. SOP is that the wheels are always chocked unless the onboard pilot has signaled them to be pulled. Simple question, who was supposed to do that? He's toast. No ifs, ands, or buts.

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  8. Theoretically, if they'd all gone to the nose and pushed to one side, they probably could have turned it some. Whether that would have been good or bad is another story (it could have rolled another 500-1000 meters and gotten to 2-3 times faster before impacting, or rolled to a stop -Who knows).

    The weight of the aircraft is actually less than those semis used in those "world's strongest man" competitions as pull toys. Of course those trucks have people ready to use the brakes when the puller reaches the finish line.

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  9. I worked on the flight deck of an Aircraft Carrier (the USS Independence and later the USS Eisenhower) and we routinely pushed aircraft backwards that had their engines running by simply pushing on hard points. Took about 10 or 12 guys but it worked. F-14's (at 72,000 pounds) down to the S-3 Viking (44,000 pound). Even the mighty F-4 phantom (I don't remember their weight) and A-6 Intruder. You just had to be careful where you put your hands when you pushed.

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