Page 18 - May24Tv2

Swift, but Methodical by Thomas P. Turner
Several years ago, a fatal mishap occurred in a Beech Duke at Wilmington, Delaware. The failure that instigated the crash would be very hard to correctly
identify in real-time from the pilot’s seat. As multiengine pilots, we’re trained to respond to the indications this failure would present in exactly the wrong way. In a single-engine turboprop, the condition might surprise us as well.
From the NTSB (Accident Number NYC08FA051):
“According to a witness, prior to arriving in the run-up area, the pilot lowered the airplane’s flaps. After the right flap fully extended, the flap key on the drive shaft inside the 90-degree drive assembly adapter fractured, in overload, in the direction of flap extension. Before takeoff, the pilot raised the flaps; how- ever, with the fractured key, the right flap would have remained fully extended. The pilot could not have identified this condition
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prior to takeoff, either visually [because of the Duke’s window design] or by means of the flap indicator, which received its input from the right flap actuator.
“The pilot subsequently took off, and the airplane turned left, but it is unknown at what point the pilot would have noted a control problem. The pilot climbed the airplane to 250 to 300 feet and allowed the airspeed to bleed off to where the airplane stalled and subsequently spun into the ground. Airplane manu- facturer calculations revealed that the pilot should have been able to maintain control of the airplane at airspeeds over 70 knots. According to the pilot’s operating handbook, the best two-engine angle of climb airspeed was 99 knots, and the best two-engine rate of climb airspeed was 120 knots.
“The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot’s failure to