Taipei, The crash of a Black Hawk helicopter in waters off Lanyu, an island near Taitung County, early this year was caused by pilots ignoring warning signals when the chopper encountered air turbulence shortly after take off, the Aviation Safety Council (ASC) said Sunday.
The UH-60M Black Hawk, operated by the National Airborne Service Corps, went missing near Lanyu on Feb. 5 after it was dispatched to transport a patient to Taitung County in southeastern Taiwan.
The helicopter was located on the seabed at a depth of about 1,000 meters near Lanyu a month later, but the wreckage was not retrieved until April 12.
The Black Hawk was carrying a pilot, co-pilot, engineer, flight nurse, one patient and a family member of the patient, and was making its way back when it disappeared from radar screens. All six have been confirmed dead.
Asked about a recently released ASC report, ASC Executive Director Kuan Wen-lin (???) told CNA that data retrieved from the chopper's Flight Recorder, made up of a flight data recorder and cockpit voice recorder, indicates the aircraft did not encounter mechanical problems before crashing.
Encountering air turbulence at low altitude, the pilot and co-pilot failed to follow standard procedures in dealing with the situation. They also ignored warning signals that flashed on the chopper's aviation guidance system, "unknowingly taking the helicopter into a critical situation," Kuan said.
According to the ASC report of the incident, the Black Hawk took off from Lanyu airport at 11:48:36 p.m. on Feb. 5. Thirty-eight seconds later it flew into air turbulence, which the pilot and co-pilot reported.
However, the helicopter did not accelerate to distance itself from the turbulence but slowed down. The pilot also changed the way he was flying, reducing torque to maintain flight altitude, the report said.
After taking off, the alarm on the helicopter's aviation guidance system sounded between 11:48:56 p.m. and 11:49:44 p.m., when it was less than 300 feet above sea level, Kuan said, noting that the alarm was reminding the pilots of flight altitude and speed.
At 11:49:57 p.m. the chopper crashed and the flight recorder stopped working, according to the report, indicating that five seconds before the crash, the pilot realized the altitude was incorrect and asked the co-pilot to check.
Flight Recorder data shows that no messages were exchanged between the two pilots about the warning signals, nor did they say out loud the helicopter's altitude and speed as required when such signals flash.
Their response deviated from standard aviation procedures, Kuan said.
He added that UH-60M Black Hawks are advanced helicopters with sophisticated instruments designed to ensure safe flights. He said it was unknown why rather than use such instrumentation the pilots decided to fly the chopper based on their own visual assessment.
This is a question any future probe will need to answer, Kuan said.
Source: Focus Taiwan News Channel