25th of December 2016, Blog #579
68 passengers and four crew were onboard a scheduled domestic ATR 72-600 flight in Indonesia, between Bandung Airport and Semarang-Achmad Airport.
The aircraft in its final position, note the collapsed landing gear and the damaged propellor (© KNKT)
At 17.34 lt (local time) the aircraft departed Bandung with the captain acting as Pilot Flying (PF) and the co-pilot as Pilot Monitoring (PM), there were no known technical issues with the aircraft at the time of departure. The flight continued without any issues and after receiving descend clearance commenced descent towards Samarang. At 18.12 lt, while flying in the dark the crew received a broadcast from Semarang Approach Control informing all traffic that rain was falling at the airport.
The PM queried ATC about the intensity of the rain. ATC replied stating it was "slight rain"
A short while later the crew were instructed to hold over waypoint KENDA at an altitude of 4000 feet, to obtain the necessary separation with a preceding aircraft. At 18.17 lt the flight was cleared to descend to 3000 feet. Subsequently, the crew received clearance to leave to hold at KENDA for an RNAV approach to runway 13 and were instructed to switch to Semarang Tower. The weather around the time of the approach was reported as follows (local time is UTC+7):
At 18.20lt the PM contacted the tower stating they were on finals and had the runway in sight, ATC instructed the flight to continue with the approach, informing the crew the wind was from 190º at 15 knots, the altimeter setting was 1008 hPa and the runway was wet.
A minute later the tower controller cleared the aircraft to land, which was confirmed by the PM who also requested the intensity of the approach lights to be reduced. This was done and the new setting was confirmed with the crew to be appropriate.
t 18.24 lt the aircraft touched down and bounced three times before settling on the runway, at that time the tower controller observed the right-wing navigation light to be noticeably lower than the left-wing navigation light and pressed the crash bell, followed by a telephone call to the Airport Rescue and Fire Fighting (ARFF) personnel, that there was aircraft accident near the taxiway D As the aircraft decelerated it moved to the right runway edge, coming to a stop near taxiway D.
The aircraft being evacuated (Source; avherald.com © Unknown)
Two minutes after touchdown the crew contacted ATC giving their position and requesting assistance, ATC replied stating help was in the way. The crew kept both engines running while awaiting the arrival of the fire brigade. At 11.29 the fire brigade at the aircraft to assist with the evacuation, on request of ATC the engines were then shut down by the crew. The evacuation was completed 10 minutes after the aircraft came to a stop. There were no injuries to the occupants. The damage to the aircraft was extensive;
The right-hand main landing gear collapsed
The right-hand propellor blades lost ~26 cm from the tip
Multiple dents in the right fuselage
The collapsed gear and damaged propellor (left) & the dented fuselage (right) (© KNKT)
The Komite Nasional Keselamatan Transportasi (KNKT - Indonesian Transportation Safety committee) was alerted and started an investigation, covering all aspects of the flight and the incident.
FDR data from the approach to engine shutdown (©KNKT)
In January 2019 the KNKT published their final accident investigation report, in this report, they identified a long list of findings and contributing factors, the main ones being;
Late flare due to the illusion of being higher than the real altitude resulting in a touchdown on the nose landing gear
Unrecovered bounced landing, resulting in a 6g vertical acceleration on the third bounce, leading to landing gear failure.
Delayed engine shutdown due to pilot consideration that the electricity for lighting on cabin passenger was needed for the passenger evacuation. (The lighting to the cabin would be available after the engine shut down and the activation of the MIN CAB LIGHT switch as described on the Emergency Evacuation on Ground checklist.)
Delayed engine shutdown went against FCOM instructions
Emergency evacuation procedures not performed correctly
No Go-Around was initiated after bounced landing, which went against FCOM instruction
The full list of findings and contributing factors, as well as several safety recommendations, can be found in the investigation report (also the source for this blog), which can be accessed by clicking on the .pdf file below;