Jetway vs. Airplane...

[Regional4life]

I don't remember all the details of the incident. But the Avro had the generators on engines 1 and 4 and the hydraulic pumps on 2 and 3. I forget now which engine was primary for the break system but either could be selected if need be. As for the incident in question, if memory serves correct from ground school it had something to do with some circuit breakers being pulled that shouldn't have been as part of their maintenance work. Keep in mind my one and only Avro ground was 2 years ago now and the story is a bit foggy. I believe that hull was turned into the fire trainer for the MEM CFR.

Close. Here's the background. MX was doing a runup to test the pressurization system and the mechanic took shortcuts. Instead of holding the squat override switches on the overhead test panel, he pulled the CB's to override the squat switch (definitely not following his job card). On completion of the runup test, he forgot to put the breakers back in. The engines thought they were in flight, so they idled at flight idle (significantly higher than ground idle). As the MX was taxiing in, he realized no brakes (the brakes don't apply when off squat switches, they stop at the anti-skid valves). He forgot about the squat switches, tried to switch to the green brakes (secondary brakes) but again, didn't work. If he would have switched to emergency brakes, he would have been fine as that automatically overrides the antiskid. But, he instead tried to use the DC pump on the overhead panel, which again, won't work because the plane thinks it's in the air. Regardless, FDR said the aircraft impacted the jetway at around 35 knots. (In otherwords, holy S$%@!!!!) Mechanic tried to lie about the incident on what happened but the little boxes that show pulled breakers don't lie. Lost his job (and a 25 million dollar airplane).

 

[Regional4life]

I should also add that he is lucky that he didn't kill anyone. The outbound Captain was standing in the jetbridge waiting for the plane when it impacted the jetway. He suffered some injuries but fully recovered.