PILOT IGNORANCE of technical systems, poor asymmetric-power handling skills and inadequate cockpit-resource management (CRM) training have been cited in the official report into the 4 April, 1994, KLM CityHopper Saab 340B accident at Amsterdam Schiphol Airport in the Netherlands.
The captain and two passengers were killed and nine people seriously injured when the aircraft crashed as the crew attempted a single-engine go-around, according to the Netherlands Aviation Safety Board (NASB).
The primary cause of the crash was identified as incorrect use of flying controls during the go-around procedure, says the NASB, citing insufficient rudder application and an attempt to start the climb too early.
On the initial climb-out from Schiphol, the aircraft, bound for Cardiff, in the UK, suffered a short-circuit in the starboard-engine oil-pressure switch, which set off a warning bell and a master-warning-panel light. The captain throttled back the right-engine power lever to flight idle, and saw the engine oil-pressure gauge reduce. Pressure remained within limits, however.
The report says that the drop was associated merely with power-reduction, and the engine was cleared for normal operation. If the engine oil-pressure had been out-of-limits - as the pilot seemed to believe - he should have shut down the engine, says the report. Selection of flight idle gives "substantially higher [propeller] drag" than shutdown, which autofeathers the propeller, says the NASB.
The pilot "...did not realise the consequences" of approaching with an engine in flight-idle, observes the report. "Power, airspeed and pitch were not stabilised" and the captain used insufficient rudder control. The resulting directional asymmetry, says the report, put the aircraft to the right of the runway, hence the captain's decision to go around.
This manoeuvre should have been possible under the circumstances, but because of a combination of "insufficient" rudder application and climbing "too early", the aircraft went out of control and crashed.
Contributory factors, says the report, were lack of crew knowledge of the engine's oil system, and of the consequences of flying with an engine in flight idle, and, finally, poor CRM.
Source: Flight International