Created Sunday, Feb 14th 2021 11:55Z, last updated Friday, Apr 8th 2022 18:08Z
A Manta Air de Havilland Dash DHC-6-300 Twin Otter, registration 8Q-RAE performing flight NR-117 from Como Malifuushi to Male (Maldives) with 6 passengers and 3 crew, landed on Male's water "north right" runway at 07:32L (02:32Z) but flipped over and came to a stop upside down. All occupants were rescued, taken to a hospital and later discharged. The flight attendant received minor injuries.
The aircraft was later recovered.
On Mar 30th 2021 the Maldives' Accident Investigation Coordinating Committee (AICC) released their preliminary report summarizing the sequence of events after stating the aircraft was landing on Male's North-Right water runway:
The FO (33, CPL, 3,299 hours total, 2,138 hours on type) was Pilot flying (PF) for this sector. Taxi-out, take-off, cruise and approach into VIA were normal. The captain (33, ATPL, 7,939 hours total, 7,270 hours on type thereof 4,138 hours in command) stated that the aircraft landing attitude was flat on this flight as was the case of all landings carried out by the FO on the previous day. The captain (PIC) believed that this could have been a factor due to the differences in landing attitudes between the ATR aircraft and Twin Otter on floats.
The aircraft, while landing touched down and veered right, and the aircraft RH wing digged into the water and took a U turn and came to rest upside down.
The cabin crew assisted the passengers to evacuate the aircraft. Soon after the accident, the MACL rescue boats arrived and rescued all the passengers.
The AICC reported:
The airplane was equipped with life jackets for each passenger seat and all crew members. Some passengers retrieved and used life jackets installed on the aircraft.
Passengers stated that they tried to hold on to the aircraft in the water and that the wreckage remained afloat through out - until they were rescued.
The AICC reported the flight attendant received minor injuries, all others remained unharmed.
The aircraft received substantial damage, the occurrence was rated an accident. The aircraft had accumulated 43,932 flight hours in 78,854 cycles. It's CoA had been last issued on Dec 17th 2020 and was valid until Dec 16th 2021. The aircraft had departed with no technical defects remaining open, the crew did not report any technical difficulties during the flight.
The AICC annotated: "There were no evidences of an activated ELT."
On Apr 8th 2022 the AICC released their final report concluding the probable causes of the accident was:
- FO maintained a flatter than normal attitude of the aircraft at touch down;
- FO released the controls too early for an aircraft operated on floats due to his flying motor skills on a land aircraft which require release of the control at touchdown;
- Loss of control of the aircraft immediately after touchdown;
- PIC did not take over the controls from FO in a timely manner;
The AICC analysed that the configuration of the aircraft was correct for landing as well as the aircraft's speed, which was deduced from CCTV.
With respect to the landing attitude the AICC analysed:
A “flatter” than normal landing attitude was performed by the FO and was area of grave concern ever since reconversion of the FO to Twin Otters took place. According to the PIC the FO tended to touchdown flat and ease the control column immediately after, as opposed to keeping the control column pulled on longer. One reason is that FO was flying ATR for a considerably long time and his mind was still conditioned to landing ATR aircraft - an acquired motor memory, an issue known.
Having observed the incorrect landing attitude practiced by the FO, the PIC guided the FO on addressing the issue in five of the seven landings carried out by the FO on the previous day, it was revealed during the interviews conducted post-accident.
Incidentally, the issue was also brought to the attention of the FO at dinner the previous night and reminded again by the PIC on approach into MLE.
The steep approach carried out by the crew prompted the PIC to instruct the FO to level off the aircraft early. FO acted accordingly, by leveling off the aircraft prior to touch down. However, due to ground effect the aircraft floated longer. Instinctively, the PIC commanded the FO to pull and hold the control column to ensure maintaining the correct attitude at touchdown. However, rather than holding on the control column longer, the FO eased the control column prior to achieving the correct landing attitude. Consequently, the RH float dug in followed by left-hand wing dropping from which the aircraft failed to recover.
The FO admitted that he tended to level off and ease the control sooner than normal after touchdown as is the case with ATR 42/72 aircraft. His mind was conditioned to landing ATR aircraft.
Past incidents and accidents revealed that pilots who transit from wheelplanes to floatplanes had difficulties in mastering the motor skills necessary to maintain the current landing attitude, in the short timeframe specified in the Operations Manuals of the operators. So was the case with the operating crew of flight NR117.
The AICC analysed with respect to the crew:
Records held with Manta confirmed that the PIC had undergone only a single Proficiency Check as opposed to two required on DHC-6 after joining Manta Air on 29th August, 2020 and is non-conformance against the requirements set forth in the Operations Manual.
Review of the training records also confirmed that the PIC had not fully completed the Training Captain Course as described in OM D, Chapter 2.6.2.1 and referenced in different sections of the OM, Part D.
...
Given the conditions, it was too early for pairing the two crew to fly
commercial flights: PIC as LTC (Line Training Captain) and FO as LIFUS (Line Flying Under
Supervision).
