Bangkok Airways Flight 125
| Bangkok Airways Flight 125 | |
|---|---|
| Accident summary | |
| Accident type | Loss of control after spatial disorientation |
| place | Koh Samui Airport |
| date | November 21, 1990 |
| Fatalities | 38 |
| Survivors | 0 |
| Aircraft | |
| Aircraft type | De Havilland Canada DHC-8-100 |
| operator | Bangkok Airways |
| Mark | HS-SKI |
| Departure airport | Don Mueang Airport |
| Destination airport | Koh Samui Airport |
| Passengers | 33 |
| crew | 5 |
| Lists of aviation accidents | |
On November 21, 1990 at around 6.15 p.m. local time on Bangkok Airways flight 125 ( flight number : PG125 or BKP125), a De Havilland Canada DHC-8-100 crashed into a coconut plantation southwest of Ko Samui airport after a failed approach . All 38 occupants were killed in the accident.
plane
The aircraft of the type De Havilland Canada DHC-8-100 with the aircraft registration HS-SKI and the serial number 172 was equipped with two engines of the type Pratt & Whitney Canada PW120A . The aircraft had completed 3416 flight hours by the time it crashed.
Flight history
The Bangkok Airways aircraft took off at 4:58 p.m. local time from Don Mueang Airport for a scheduled flight to Ko Samui . The tower in Ko Samui first contacted the pilots at 5:45 p.m. At that time the aircraft was about 220 kilometers (120 NM ) from the airport. The crew was informed that runway 17 was in operation. According to the tower, the weather was fine, with a rain zone southwest of the runway. The pilots were instructed by the air traffic controller to inform him of a distance of 60 NM (93 km) from the airport. The pilots failed to send this message and only made contact with the tower again 20 NM (37 km) from the airport. They received the information that runway 35 (opposite direction) was in operation and the wind was blowing from a direction of 30 degrees. The wind speed was 10 knots (18 km / h) and the visibility on the ground was six kilometers. A minute later, the pilots were informed that the weather east of the airport was still good, but that heavy rain showers were coming down to the west. You have been asked to report that the landing gear is extending . The approach lights at the airport went into operation a few minutes later.
The air traffic controller in the tower observed the aircraft coming from the north east of the airport on a counter-approach with the landing gear already extended, without the pilots having notified this. To the south of the field, the aircraft started transverse approach to the west. At this point in time, visibility at the square had deteriorated significantly due to drizzle and haze. The crew was unable to establish visual contact with the runway during the transverse approach and therefore did not turn into the final approach . Instead, the machine flew with extended landing gear and fully extended landing flaps in a westerly direction and thus into a heavy rain zone with even poorer visibility. The air traffic controller, who noticed the missing final approach, asked the crew whether they would turn into the sea in a left turn, but received no answer. When asked, the pilots stated that they had no sight of the runway and needed information as to whether they should fly to the right or left. Due to the presumed spatial disorientation of the crew, the DHC-8 had in the meantime assumed a bank angle to the left, unnoticed by the pilots. The air traffic controller informed the crew that they should fly to the left as there were hills on their right side.
The captain, who had immediately taken over from the copilot at the controls, then brought the machine, which was already flying at a left bank, into an even steeper left turn by means of an abrupt steering maneuver, so that it tilted over the wing with a roll angle of 89 degrees and into an uncontrolled one Descent passed. With a left incline of 75 degrees and a nose pointing 36 degrees downwards (negative pitch), the DHC-8 hit a coconut plantation five kilometers southwest of the airport at 147 knots (272 km / h). With the exception of the last tail section, the aircraft was completely destroyed and burned out. None of the 38 occupants survived the impact.
Cause of accident
In the opinion of the investigation commission, the accident was caused by the inadequate division of labor on board and the resulting disorientation of the pilots. Even before the start of the transverse approach, the crew had shown themselves to be unfocused and had failed to report the distance report requested by the air traffic controller and the extension of the landing gear. The investigators also criticized the inadequate flight planning of the crew.
The approach to Ko Samui was initially carried out by the co-pilot, while the captain took on the function of “ pilot not flying ”. When the machine was in the transverse approach, the pilots gave up this division of labor and began to look for the runway together, where they probably both no longer paid attention to the instruments. The machine began, presumably unnoticed by them, to roll slowly to the left around its longitudinal axis .
The stipulated standard procedure for an unsuccessful approach to runway 35 provided for a go - around followed by a right turn out to sea. Because the aircraft was not in the final approach, but still in the transverse approach, the inadequately prepared crew appeared to be completely overwhelmed with the situation. The air traffic controller's question as to whether they would turn left (instead of right) into the sea probably contributed to further confusion among the pilots. The increasingly spatially disoriented copilot ("pilot flying") finally asked the captain to take control of the aircraft. This probably took place without the master checking the altitude and attitude of the aircraft using the instruments. Immediately after the master took over the controls, the air traffic controller announced that he would turn left due to the hills. The master then carried out an abrupt deflection of the aileron , which further increased the existing left bank angle and brought the aircraft into an uncontrolled flight condition within seconds.
Web links
Flight accident data and report DHC-8-100 HS-SKI in the Aviation Safety Network , accessed on March 10, 2017.
Individual evidence
- ↑ a b c d e f g ICAO Aircraft Accident Digest No. 37: 1990, Circular 263-AN / 157, Montreal 1996, pages 231-245.
Coordinates: 9 ° 30 ′ 21 ″ N , 100 ° 2 ′ 58 ″ E