For G0ULI
“This was the only recorded accident involving an Electra that involved loss of aileron control....”
Thanks G0ULI.
I think that’s right. However, you don’t mention the many aileron issues (all potentially capable of causing loss of all aileron) that pilots had written in the aircraft’s log’s attached squawks.... and that’s but one airplane in a large fleet.
Common in the Fleet? How were the many squawks addressed? CAB stated “not very well, even casual...”
Question. How many times had this flight crew operated N137US? Were they familiar with the aircraft’s problems?
On the day, the co-pilot told us what was wrong, told us what they were doing to correct, and what was happening to the flight path. Had they ever discussed this individual aircraft, had other pilots? Almost certainly yes. In the flying fraternity, it’s called a “heads up”.
It would not surprise me in the least if other pilots had reached a consensus of sorts:
“Boost issues...” It was the squawks that finally motivated NW to replace the boost unit, the thinking being: “maybe this will help.”? Who does not know a mechanic whose theory of repairs is: “keep replacing parts until the problem goes away”?
It was noted that this boost removal/replacement was the first NW had done. Was the boost unit the cause of all the squawks? It wasn’t the power arm? The Control Valve? The pumps? The check valves? A hung pushrod in the wing? What was the methodology used to chase down these potential and hazardous issues?
As to the “damage” that shows separation of the cable, it was not evidence that led to the opinion about cable separation, it was the opinion that led to the “evidence”, with an experiment designed by Lockheed to prove the opinion, not to challenge it.......
Let’s review the squawks, informally
Aileron Slop. Yoke vibration. Chatter with any input. Sluggish response.
Off the top of my head, this sounds not like the boost unit ouput at all. It suggests a problem with the control valve, and its plumbing.
Last edited by Concours77; 11th Jan 2018 at 15:19.