De Havilland DHC-6 Twin Otter

The twin engine airplane departed Dire Dawa in the morning on a flight to Harar Meda Airbase located in Debre Zeit, carrying 15 Army officers and three civilians on behalf of the Ethiopian Army. While descending to Harar Meda, the airplane crashed in unknown circumstances in a wooded area located in Mojo, some 17 km southeast of the airfield. The aircraft was totally destroyed and all 18 occupants were killed, among them two children. Operated on behalf of the Ethiopian Army with dual registration ET-AIU/808.

The pilot of the twin-engine, turbine-powered airplane reported that, while providing flights for skydivers throughout the day, he had a potential new hire pilot flying with him in the right seat. He added that, on the eighth flight of the day, the new pilot was flying during the approach and "approximately 200 feet south from the threshold of [runway] 15 at approximately 15 feet AGL [above ground level] the bottom violently and unexpectedly dropped out. [He] believe[d] some kind of wind shear caused the aircraft [to] slam onto [the] runway and bounce into the air at a 45 to 60-degree bank angle to the right." The prospective pilot then said, "you got it." The pilot took control of the airplane and initiated a go-around by increasing power, which aggravated the "off runway heading." The right wing contacted the ground, the airplane exited the runway to the right and impacted a fuel truck, and the right wing separated from the airplane. The impact caused the pilot to unintentionally add max power, and the airplane, with only the left engine functioning, ground looped to the right, coming to rest nose down.

The pilot reported that he was landing in gusty crosswind conditions following a parachute jump flight, and that the gusty conditions had persisted for the previous 10 skydiving flights that day. The pilot further reported that during the landing roll, when the nose wheel touched down, the airplane became "unstable" and veered to the left. He reported that he applied right rudder and added power to abort the landing, but the airplane departed the runway to the left and the left wing impacted a tree. The airplane spun 180 degrees to the left and came to rest after the impact with the tree. The left wing was substantially damaged. The pilot did not report any mechanical malfunctions or failures with the airplane that would have precluded normal operation.

As per the flight plan submitted on 23rd February 2016, the aircraft was scheduled for VFR flight to Jomsom (VNJS) on 24th February with estimated off-block time of 01:00, intended cruising speed of 150 knots, intended level of 10,500 ft and via direct track. The first and second alternate aerodromes were Bhairahawa (VNBW) and Pokhara (VNPK) respectively and estimated elapsed time was 20 minutes with the fuel endurance of 2 hours and 30 minute. Based on the information from the CVR, FDR and ATC records, the following description of the history of the flight was reconstructed: At 01:55, the first-officer contacted Pokhara tower requesting Jomsom and Bhairahawa weather. Upon receiving Jomsom weather which was 8 km visibility towards Lete (arrival track) and foothill partially visible; at 01:56 F/O requested start-up for Jomsom. First-officer then briefed the weather to the captain, in response to this the captain responded by saying 'Let‘s have a look, if not possible we will return' (Translated from Nepali conversation). While performing the 'before start checklist', they received weather of Bhairahawa as closed. After completing the checklist and start-up the first-officer at 02:00 requested taxi clearance. The ATC informed runway change to 22 instead of runway 04 and gave taxi clearance. At 02:03 while taxiing the captain considering bad weather condition expressed his concern over the runway change with F/O but failed to express it to the ATC. As briefed by captain earlier, the control was transferred to F/O and at 02:04 F/O made a normal take-off. At 02:08 the captain reported 5 miles at 6,200 ft to ATC. At 02:09, while passing through 7,000 ft the captain informed the actual weather, which was light haze, mountain not visible but had ground contact, to an ultra-light aircraft upon his request. As per the cockpit conversation, the crew were comparing the base of the cloud which was higher than the day before and proposed to continue climb to 12,500 ft if not on-top of the cloud at 10,500 ft. Around 5 miles before Ghorepani passing 10,100 ft, the captain told that cells were still present so advised F/O to continue climb to 12,000 ft and told that they will proceed till TATOPANI and decide to continue or divert. At 02:14 approaching GHOREPANI and passing 11,400 ft, Captain told F/O to maintain level to be in between the cloud layers and briefed F/O that if they had to divert it would be a left turn. At the same time captain asked repeatedly to F/O if his side was raining for which F/O told and confirmed not visual, after which captain told they would see and decide (regarding continuation of flight). At 02:14:50 while over Ghorepani area at 11,500 ft the EGPWS TERRAIN alert and at 02:14:52 PULL UP warning came while they were not visual and at 02:15:01 it was stated that they were visual and by 02:14:53 the warning stopped. At 02:15 while maintaining 11,500 ft the captain reported ATC that they are at Ghorepani at level 10,500 ft after which frequency changeover to Jomsom tower was given. At 02:15:27 the captain instructed F/O to maintain heading of 3300 and flight level just below the cloud, after which a shallow descent was initiated. At this time captain asked F/O if his side was visual, in response F/O replied somewhat visual. The Captain then instructed F/O to descent to 10,000 ft. Once the descent was started at 02:15:55 passing 11,000 ft an OVERSPEED warning sounded in the cockpit for 2 seconds as the speed reached 152 knots. At 02:16 while passing 10,700 ft captain advised F/O to make a left turn so that it would be easy to turn if required as he was able to see his side. Then F/O asked if left side was visual for which the captain informed that not that side (towards the track) but somewhat visual to the left of him and told that the TRACK TO GO was TO THE LEFT whereas they were actually left of the track and had descended to 10,300 ft. At 02:17:58 EGPWS TERRAIN alert sounded when the aircraft was at 10,200 ft and descending on heading of 3210 with right bank angle of around 30 . At 02:18:06 when the aircraft had descended to 10,100 ft the PULL UP WARNING sounded for which the captain said not to worry and at 02:18:12; when the aircraft was at 10,000 ft the captain took-over the control, continued descent and asked F/O if his side was visual. The F/O informed that right side was not visual at all by which the aircraft had continued shallow descent on heading 3250 with right bank angle reaching up to 130 at 2:18:19 and by 02:18:23 the aircraft once again returned back to 0° bank angle. At 02:18:23 the captain started left bank followed by right bank again while still on a shallow descent until 02:18:27.Upon reaching 9,850 ft (lowest altitude) the aircraft started very shallow climb. At 02:18:35 when aircraft was 9,920 ft the captain told F/O that they reached Landslide (a checkpoint which is on track to Jomsom on the right side of the Kali-Gandaki River). At 02:18:44 when aircraft reached 10,150 ft captain told ―what I will do is now I will turn to heading of LETTE‖ (another way point on route to Jomsom); while the PULL-UP warning was continuously sounding. At 02:18:49 when the aircraft was at 10,300 ft right bank angle increased up to 16° with pitch up attitude of 7°. At 02:18:52 the captain told that he would start climb when the aircraft had reached 10,350 ft; pitch attitude of 10° and still on right bank. The aircraft reached zero degree bank at 02:18:53 and started shallow left bank with pitch attitude of 12° nose up. By 02:18:57 the bank angle reached 200 left with pitch attitude of 11.8 and altitude of 10,550 ft and captain was still questioning F/O about the visibility towards his side but F/O informed his side not visible completely. The last data recorded in FDR was at 02:19:03 when the altitude had reached around 10,700 ft; pitch attitude of 7° nose up and left bank angle of 25° heading of 335° with EGPWS PULL-UP warning ON.

On 2 October 2015, a DHC-6 Twin Otter, registered PK-BRM, was being operated by PT. Aviastar Mandiri as a scheduled passenger flight with flight number MV 7503. The aircraft departed from Andi Jemma Airport, Masamba (WAFM)1 with the intended destination of Sultan Hasanuddin International Airport, Makassar (WAAA) South Sulawesi, Indonesia. On board the flight were 10 persons consisting of two pilots and eight passengers, including one company engineer. The previous flights were from Makassar – Tana Toraja – Makassar – Masamba – Seko - Masamba and the accident flight was from Masamba to Makassar which was the 6th sector of the day. The aircraft departed from Masamba at 1425 LT (0625 UTC2 ) with an estimated time of arrival at Makassar of 0739 UTC. The Pilot in Command (PIC) acted as Pilot Flying (PF) while the Second in Command (SIC) acted as Pilot Monitoring (PM). The flight was conducted under the Visual Flight Rules (VFR) and cruised at an altitude of 8,000 feet. At 0630 UTC, the pilot reported to Ujung Pandang Information officer that the aircraft passed an altitude of 4,500 feet and was climbing to 8,000 feet. The Ujung Pandang Information officer requested the pilot of the estimate time of aircraft position at 60 Nm out from MKS VOR/DME. At 0632 UTC, the pilot discussed about the calculation of estimate time to reach 60 Nm out from MKS and afterward the pilot informed Ujung Pandang Information officer that the estimate at 60 Nm was at 0715 UTC. At 0633 UTC, the Ujung Pandang Information officer informed the pilot to call when reaching 8,000 feet and was acknowledged by the pilot. At 0636 UTC, the pilot informed the Ujung Pandang Information officer that the aircraft had reached 8,000 feet and requested the squawk number (ATC transponder code). The Ujung Pandang Information officer acknowledged and gave the squawk number of A5616, which was acknowledged by the pilot. At 0637 UTC, the pilots discussed to fly direct to BARRU. BARRU is a town located at about 45 Nm north of Makassar. Both pilots agreed to fly direct and the SIC explained the experience of flying direct on the flight before. At 0651 UTC, the PIC told the SIC that he wanted to climb and one second later the CVR recorded the sound of impact.

Following an uneventful skydiving mission over the Dubai Drop Zone, the pilot was returning to his base. Upon landing on runway 06, the twin engine aircraft went out of control, veered off runway to the left, struck an embankment and came to rest with the right wing torn off. The pilot was uninjured and the aircraft was damaged beyond repair.

The airline transport pilot was conducting a cross-country aerial observation flight in the multiengine airplane. The pilot reported that the airplane was on the final leg of the traffic pattern when he reduced the power levers for landing and noticed that the right engine sounded like the propeller was moving toward the beta position. The pilot increased the engine power, and the sound stopped. As the airplane got closer to the runway, he decreased the engine power, and the sound returned. In addition, the airplane began to yaw right. The pilot applied left aileron and rudder inputs to remain above the runway centerline without success. While over the runway, the pilot reduced the engine power to idle, and the airplane continued to yaw right. The pilot applied full power in an attempt to perform a go-around; however, the airplane yawed about 30 degrees off the runway centerline, touched down in the grass, and impacted trees before coming to rest. The right wing, right engine, and right propeller assembly were impact-separated. The right engine propeller came to rest about 50 ft forward of the main wreckage, and it was found in the feathered position. A review of maintenance records revealed that the right propeller had been overhauled and reinstalled on the airplane 2 days before the accident and had operated 9 hours since that time. Subsequent testing of the right propeller governor revealed that it functioned without anomaly; however, the speed settings were improperly configured. Further, the testing revealed that the beta valve travel from the neutral position was out of tolerance. Although this could have let oil pressure port to one side of the spool or the other and, thus, changed the propeller blade angle, it could not be determined whether this occurred during the accident landing. Impact damage precluded examination of the right propeller governor control linkage; therefore, it could not be determined if it was inadequately installed or rigged, which could have resulted in the propeller moving into the beta position. The investigation could not determine why the right propeller moved toward the beta position as engine power was reduced, as reported the pilot.