This one is interesting...
This time, it involves prop overspeed on descent and approach; the Swedish air accident investigation branch (SHK) found that in a number of occasions in which this occurred (4 times in one acft!), on none of these occasions was the checklist correctly followed. The report criticised SK and Bombardier training, saying that the checklist itself was difficult to follow.
In one particularly serious incident, the aircraft was approaching Kalmar and became seriously destabilised, to the extent that the ATC officer alerted fire crews; a safe landing was made, but the approach was heavily criticised by the SHK.
http://www.flightglobal.com/articles/2007/11/08/219260/inquiry-into-destabilised-sas-q400-approach-finds-checklists-not-followed.htmlWhile the Q400 managed to land, with no injuries to its 73 occupants, SHK says “at no stage” did the aircraft meet the requirements for a stabilised approach.
“[We] cannot judge how close the aircraft was to a crash in respect to height, speed and controllability, but can conclude that both pilots on separate occasions during the approach were convinced that they would not reach the runway,” it says, highlighting the “balanced” crew resource management which ultimately kept the Q400 under control.
SHK says the overspeed checklist procedure was “not completely clear”, notably regarding the crucial issue of retarding the throttles.
“There is no information in the checklist to say that a power lever should not be placed at flight-idle,” says SHK. “Nor was the company informed of the potentially dangerous situation that can arise by having an engine power-lever in flight-idle if the propeller is not feathered.”
Sounds remarkably similar to the accounts of the planes engines over speeding....
