Landing (descent or approach)

The four engine aircraft departed Zahedan on a flight to Kerman, carrying 257 passengers and a crew of 18, most of them members of the Revolutionary Guards. On board were also several high ranking officers who just conducted a visit of the province of Zahedan, taking part to a narcotic control program. While descending to Kerman Airport by night, the crew encountered poor weather conditions with heavy snow falls and strong winds. On approach, the aircraft struck the slope of Mt Sirach located 32 km from the airport. First rescuers arrived on the scene the next morning. The wreckage was found about 100 metres below the summit and all 275 occupants have been killed.

The airplane joined the inbound course for the GPS instrument approach between the intermediate approach fix and the final approach fix, and maintained an altitude about 200 feet below the sector minimum. The last radar return revealed the airplane to be about 3/4 nautical miles beyond the final approach fix, approximately 1,000 feet left of course centerline. An initial tree strike was found about 1 nautical mile before the missed approach point, about 700 feet left of course centerline, at an elevation about 480 feet below the minimum descent altitude. Witnesses reported seeing the airplane flying at a "very low altitude" just prior to its impact with hilly terrain, and also described the sound of the airplane's engines as "really loud" and "a constant roar." Night instrument meteorological conditions prevailed at the time of the accident. There was no evidence of mechanical malfunction.

The crew was completing a local training flight at Braasschaat AFB. For unknown reasons, the twin engine aircraft landed hard and bounced several times before coming to rest on the runway. Both pilots escaped with minor injuries and the aircraft was damaged beyond repair.

Carrying 31 tons of telecommunications equipments for a Portuguese telephone company, the aircraft departed Macau to Baucau with two passengers and four crew members. On approach, the aircraft impacted terrain near Caicido village during a landing approach, about 1 NM (1.87 km) to the northwest of Cakung Airport, Baucau, Timor-Leste. The pilot in command was the handling pilot during the descent and approaches at Baucau. The aircraft was destroyed by impact forces and a severe post-impact fire, and the six occupants were fatally injured. The occupants included the flight crew, which comprised the pilot in command, the copilot, the flight navigator and the flight engineer, and two loadmasters who did not form part of the flight crew. At the time of the occurrence, there was low cloud near the aerodrome.2 Witnesses at the aerodrome estimated the cloud base to be about 1,000 ft (305 m) above ground level, and visibility to be about 1,500 m (0.8 NM). Before the aircraft’s departure from Macau, the flight crew was provided with notices to airmen (NOTAMs) and weather forecast information for the planned flight. The weather information provided to the flight crew did not include a terminal aerodrome forecast (TAF), or an aviation routine weather report (METAR) for Baucau. Those weather forecasts were not produced for Baucau.

Following an uneventful flight from Manaus, the crew started the descent to Rio Branco-Presidente Médici Airport runway 06 in marginal weather conditions with limited visibility due to fog. After passing the MDA at 1,150 feet, the crew continued the approach with an excessive rate of descent of 1,222 feet per minute. At a height of 57 feet, the aircraft struck trees located 360 metres short of runway 06 threshold. The engines lost power, the aircraft lost speed and height then struck the ground about 100 metres short of runway. Upon impact, the undercarriage were torn off and the aircraft slid on a distance of 600 metres before coming to rest. All 95 occupants escaped uninjured while the aircraft was destroyed.

The airplane impacted a dirt field and a power line following a loss of control during a simulated engine failure while on a Part 135 proficiency check flight. Both pilots were seriously injured and could not recall any details of the flight after the simulated engine failure. Witnesses observed the airplane flying on a westerly heading at an altitude of 100 to 200 feet, and descending. They heard the sound of an engine “surging” and observed the airplane’s wings bank left and right. The airplane continued to descend and impacted the ground and power lines before becoming inverted. A pilot-rated witness reported that he observed about ¼ inch of clear and rime ice on the airplane’s protected surfaces (deice boots) and about ½ inch of ice on the airplane’s unprotected surfaces. An NTSB performance study of the accident flight based on radar data indicated that the airplane entered a descent rate of 1,300 feet per minute (fpm) about 1,100 feet above the ground. This rate of descent was associated with a decrease in airspeed from 130 knots to 92 knots over a span of 30 seconds. The airplane’s rate of descent leveled off at the 1,300 fpm rate for 45 seconds before increasing to a 2,000 fpm descent rate. The true airspeed fluctuated between a low of 88 knots to 102 knots during the last 45 seconds of flight. According to the aircraft manufacturer, the clean, wing flaps up stall speed was 78 knots. However, after a light rime encounter, the Pilot’s Operating Handbook (POH) instructed pilots to maintain additional airspeed (10 to 20 KIAS) on approach “to compensate for the increased pre-stall buffet associated with ice on the unprotected areas and the increased weight.” With flaps up, a minimum approach speed of 105 KIAS was recommended. The POH also stated that a significantly higher airspeed should be maintained if ½ inch of clear ice had accumulated on the wings.

The airplane collided with obstructions following a loss of power in one engine during a missed approach. Following the collision sequence the airplane came to rest upright about 500 feet from the approach end of the runway and was destroyed in a post-impact ground fire. The pilot told a responding sheriff's deputy and a Federal Aviation Administration (FAA) inspector that he made the ILS approach to land and initiated a missed approach. When he added power, the left engine sputtered and the airplane veered to the left. He activated the fuel boost pump, but the airplane contacted obstructions and crashed. The responding sheriff's deputy also observed the accident. He heard an engine of an airplane making unusual sounds. The engine "seemed to get quiet and then revved higher as if to climb." He looked in the direction of the sound and saw a series of blue flashes and then an orange fireball. The deputy reported that there was a dense fog in the area at the time. At the time of the accident, the airport's weather conditions were reported as 100 feet overcast and 1/4-mile visibility in fog. The landing minimums for the ILS approach are 200 feet and 1/2-mile. According to the operator's records, when the airplane departed from Ukiah, its gross takeoff weight was about 5,909 pounds. The pilot operating handbook (POH) for the airplane lists the following items in the single engine go around checklist: 1) Throttle full forward; 2) wing flaps up; 3) when positive climb rate achieved, gear up; 4) ensure the inoperative engine is feathered. For a gross weight of 5,900 pounds, and the existing atmospheric conditions, the single engine climb performance chart shows an expected positive rate of climb of 500 feet per minute if the airplane was configured correctly. The chart also lists the following subtractions from that performance for the listed condition: 1) -400 fpm for wind milling inoperative engine; 2) -350 feet for landing gear down; 3) -200 fpm for flaps extended to 15 degrees. Examination of the wreckage disclosed that neither engine's propeller was feathered, the landing gear was down and the flaps were extended to 10 degrees. Without the airplane configured correctly for the single engine missed approach, the net climb performance would be a negative 400 feet per minute. There were no discrepancies noted with the airframe examination. The engine examination revealed no mechanical anomalies with either engine that would have precluded normal operation. 14 CFR 135.224 states that a pilot cannot initiate an approach if the weather conditions are below landing minimums if the approach is started outside of the final approach fix. The pilot can continue the landing if they are already established on the approach and the airport goes below landing minimums. According to the operator's FAA approved operating specifications, the operator had not been approved for lower than standard landing minimums.

After landing on runway 15 at Melilla Airport, the pilot-in-command noticed that he could not engage the ground idle/reverse of both propellers, and that the aircraft did not brake normally. The aircraft started to deviate to the left of the runway axis while both pilots were applying brakes. After tyre n°3 burst, the deviation continued until the aircraft left the paved surface of the runway and finally fell through an embankment with around 15 metres of height located at the end of runway 15. The aircraft was destroyed and the pilot-in-command and other nine people suffered minor injuries. There was no fire.

During the takeoff roll at Yacuiba Airport, at V2 speed, the right engine lost power. The captain decided to continue the takeoff procedure. During initial climb, decision was taken to return for an emergency landing and the crew shut down the right engine and feathered its propeller. After touchdown on runway 20, the aircraft was unable to stop within the remaining distance, overran, lost its nose gear and collided with bushes and small trees, coming to rest about 50 metres past the runway end. All 21 occupants escaped uninjured while the aircraft was damaged beyond repair.

The aircraft departed Brazzaville on a delivery flight to Douala. While cruising by night over Gabon, the crew informed ATC about technical problems, declared an emergency and elected to divert to the nearest airport which was Ndjolé. This airfield was not equipped with any runway or approach lights nor any navigation aids. The crew completed several circuits over the city then people parked their cars along the airstrip so the crew was able to land. After four unsuccessful attempts, the crew tried to land but the aircraft flew over the runway without landing, passed over the Ogooué River and eventually crashed in a wooded and swampy area. The crew of two helicopters from the Gabonese Air Force found the wreckage the following day. The aircraft was destroyed and all seven occupants were killed. Until few days prior to the accident, the aircraft was operated by Pont Aviation which bankrupted, so it was transferred to another operator in Cameroon.