NAMC YS-11

Following an uneventful flight from Saint Louis, a Twin Otter operated by Air Sénégal was cleared to descend to Dakar-Yoff Airport and was instructed to maintain 3,000 feet over YF VOR. At the same time, the NAMC YS-11 departed Dakar-Yoff Airport on a regular schedule flight to Banjul. Registered C5-GAA, the aircraft was carrying 34 passengers and a crew of four. Its pilots were instructed to climb via radial 140 and maintain the altitude of 2,000 feet while over YF VOR. When both aircraft reached the YF VOR, they collided. While the crew of the NAMC was able to return to Dakar and land safely despite the left wing was partially torn off, the Twin Otter entered an uncontrolled descent and crashed in the sea few km offshore. All three occupants were killed.

The crew departed Wilmington-Air park (Clinton County Airport) on a local training flight. On final approach to runway 22, the crew forgot to lower the undercarriage and the aircraft landed on its belly. It slid for few dozen yards and came to rest on the main runway. All three occupants escaped uninjured while the aircraft was damaged beyond repair.

An IFR flight was terminated with a visual approach. Conditions were conducive to airframe icing. The aircraft was being positioned empty, with a cg at 22.1% mac. On short final, at approximately 400 feet agl, 35° of landing flap was selected. The aircraft was observed to pitch downward to an unusual attitude and to enter a steep descent. A partial recovery was observed before the aircraft impacted a dirt hill 500 feet short of runway 28. Examination of the airframe after the accident revealed 1/2 to 3/4 inch of rime ice adhering to the leading edge of the horizontal stabilizer. No ice was found on any other portion of the airframe. Evidence in the cockpit indicated that engine, pitot, and windshield anti-ice systems were on, but wing/empennage deice was off. No evidence of a powerplant or systems malfunction was found. Both pilots were killed.

During the takeoff roll on runway 25, as V2 speed was reached, the copilot (pic) started the rotation but found the elevator control too heavy and decided to reject the takeoff. The crew initiated an emergency braking procedure but unable to stop within the remaining distance, the aircraft overran and plunged in the Nakaumi Lake. All 52 occupants were rescued, among them eight were injured. The aircraft was damaged beyond repair.

The flight crew failed to adhere to appropriate procedures and directives when they failed to select the hp cock levers to the hswl (lock out) position while performing an approach to landing stall during a training/test flight. When stall recovery was initiated, both propellers 'hung up' when the high (cruise pitch) stops of each propeller failed to withdraw. As the power levers were advanced, turbine gas temperatures (tgt's) exceeded limitations; the left propeller auto-feathered, the right propeller was later feathered by the captain. Restart procedures were attempted without success, and a forced landing in a plowed cornfield ensued. Examination of the engines revealed that the turbines had been 'subjected to severe (and destructive) thermal degradation during operation' as a result of the propellers being constrained during low speed operations. Testing of the relays revealed that the high stop withdrawal relay for the right propeller functioned intermittently. All three crew members escaped uninjured.

Following an uneventful flight from Sapporo, the crew started the descent to Nakashibetsu Airport in marginal weather conditions. On final, while completing a last turn to the left at an angle of 30°, the aircraft struck the ground and crash landed in a snow covered field (40 cm deep snow). It slid for few dozen meters and came to rest 100 meters short of runway 23 threshold, broken in two. 31 occupants were injured and 22 other occupants escaped uninjured.

On final approach to Mactan Island, the crew encountered technical problems with the left engine. The airplane lost height and crashed into the sea few km offshore. All 25 occupants were rescued while the aircraft sank by a depth of about 5 meters. It appears the turbine temperature was 850° C.

The approach to Navegantes-Itajaí Airport was completed in a visibility limited to 500 meters due to foggy conditions. The airplane landed about 460 meters past the runway threshold. After touchdown, the airplane became unstable, veered to the right and collided with runway lights. The nose gear and the right main gear collapsed and the airplane came to rest. Both pilots were uninjured while the aircraft was damaged beyond repair.

En route from Athens to Larisa, the crew was informed by ATC that Larisa Airport was closed to traffic due to poor weather conditions and was rerouted to Kozani. While descending to Kozani Airport in poor weather conditions, at an altitude of 4,265 feet, the twin engine airplane struck the slope of a mountain located about 25 km south of the airfield. The airplane disintegrated on impact and all 50 occupants were killed. At the time of the accident, the mountain was shrouded by clouds and the visibility was limited to 20 metres.

Few minutes after takeoff from Osaka-Itami Airport, bound for Okinoshima (Oki Island) on flight JD621, the crew informed ATC about technical problems and was cleared to return for an emergency landing. Upon touchdown on runway 32R, control became difficult after a tire burst on the right main gear. The airplane veered to the right, contacted soft ground and passed over a drainage ditch before coming to rest. All 22 occupants were evacuated safely while the aircraft was damaged beyond repair.