On 4 April 2011 a Georgian Airways Bombardier CRJ100ER (4L-GAE) crashed following a sudden loss of height on final approach to Kinshasa, Democratic Republic of the Congo. The official investigation believes it encountered a severe microburst associated with a thunderstorm squall line. The aircraft had been cleared to conduct a straight-in localiser approach to runway 24 on a flight from Kisangani on behalf of the United Nations. The aircraft, below the 472ft minimum descent height on short final approach, encountered rain and the pilots lost sight of the runway. As the aircraft approached 400ft the aircraft hit turbulence, “probably” a microburst, which triggered a windshear alert. At 224ft and they opted to execute a go-around. “During the process of go-around, a positive rate of climb was established with appropriate airspeed,” the report says. The investigators rule out the effects of somatogravic illusion – a false impression that the nose has pitched steeply upward – as a contributory cause. The aircraft then pitched from 4-5° nose-up to 7° nose-down in a “very short time”, and rapidly lost height. “Before the crew could react to the pitch down and recover from the steep descent, the aircraft impacted the terrain,” the report adds. It struck the ground to the left of the runway threshold at 180kt with 10° nose-down pitch, coming to rest inverted some 400m beyond the initial impact point. Only one passenger survived; all 32 others on board were killed.
On 28 April 2014 a Peach Aviation Airbus A320 approaching runway 18 at Naha, Japan, descended to just 240ft above water after deviating prematurely from its assigned approach altitude, according to the Japan Transport Safety Board. The crew had originally intended to carry out a VOR approach to the airport but subsequently requested precision approach radar guidance – the captain’s first PAR approach in “a long time”, the inquiry says. The JTSB notes that there was poor visibility in cloud, which prevented sight of the airport and the surface of the sea. The aircraft had been conducting an approach to Naha’s runway 18, flying level at 1,000ft, but the captain activated the vertical speed function – which had been pre-set to 900ft/min descent rate – at a distance of 5.7nm from the airport, when this should not have been done until 3nm from the runway. The aircraft descended unchecked and had reached a distance of 4nm from the airport when the air traffic controller warned that the flight was too low. Around the same time the enhanced ground-proximity warning system on the A320 issued a “too low, terrain” warning and, a few seconds later, a “pull up” instruction. The aircraft reached a minimum height of 241ft before the crew executed a go-around.
On 22 November 2015 an Avia Traffic Boeing 737-300 (EX-37005) had been descending towards the Kyrgyz city of Osh in poor visibility. Conditions were below minimums for a Category I instrument approach to runway 12, and the crew eventually executed a go-around rather badly. Russia’s Interstate Aviation Committee (MAK) says the go-around should have been started at a height of 60m but it was belatedly initiated at 45m. “The decision to go around was made correctly,” it says. “But the action commenced with some delay.” The captain applied go-around thrust, and called for flap retraction, but responded to the natural pitch-up motion of the aircraft by pushing forward on the yoke. Investigators suggest that the captain could have been reacting to an acceleration-induced somatogravic illusion and that this could possibly have been exacerbated by fatigue. As a result the aircraft, which was just 38m above the runway and travelling at 146kt, continued to descend instead of climbing away. The crew failed to communicate adequately with one another and prematurely initiated landing-gear retraction before verifying that the 737 had achieved a positive climb. Audible “don’t sink” warnings were triggered, but although the descent rate in the last 2s of flight had been reduced, the aircraft struck the runway at 178kt airspeed. The landing-gear was only 4s into its 9s retraction cycle when the impact occurred. After runway contact the aircraft climbed away. Bishkek – the aircraft’s point of departure – was also the alternate airfield, but because the impact had damaged the right-hand CFM56 engine and its hydraulic systems, the pilots opted to attempt an emergency landing in Osh despite the poor weather. During the Osh landing the gear collapsed and the aircraft overran the runway. But the MAK credits the captain with “skilfully” executing the final landing, given poor weather and the state of the aircraft – which was operating on a single engine with flaps at 15°. There were no fatalities among the 159 occupants.
On 6 November 2015 the crew of a Batik Air Boeing 737-900ER (PK-LBO) failed to recalculate the aircraft’s landing distance and overran runway 09 at Yogyakarta’s Adisucipto International airport. Indonesia’s National Transport Safety Committee (NTSC) says the aircraft was operating a domestic flight from Jakarta international airport with 168 passengers and crew on board. During the approach to Yogyakarta, the flightcrew received weather information which caused them to configure flaps at 40° and use auto-brake setting three. After noticing cumulonimbus clouds on the radar, the crew changed the setting to 30° flaps as a windshear precaution. About 2min later, the crew contacted Adisucipto tower and established the aircraft to intercept the runway 09 localiser. They also changed the auto-brake selection to maximum, after being advised that the runway was wet. The 737 touched down 427m beyond the threshold, and maximum reverse-thrust was applied. As it approached the end of the runway, the aircraft’s auto-brake was overridden by maximum manual braking, and the pilot-in-command turned the aircraft to the left. The aircraft stopped 84m beyond the end of the runway, and 80m left of the runway’s centreline extension. The aircraft suffered damage to its belly, and the lock pin of the front nose gear broke into three pieces, causing the nosewheel to fold backwards. The NTSC noted that the crew failed to recalculate the landing distance after changing the flap configuration. The late touchdown, coupled with the use of lower brake pressure, was insufficient for the aircraft to stop before the end of the runway.
On 2 November 2010 Lion Air failed to rectify an auto speed-brake fault on one of its Boeing 737-400s (PK-LIQ), and as a result it overran the runway at Pontianak. The aircraft was operating a service to Pontianak from Jakarta international airport, and the crew were aware of difficulties in selecting thrust reversers and speed brake deployment on the aircraft. This had been previously reported 13 times, according to Indonesia’s National Transportation Safety Committee in its final report on the accident. As the crew made their approach to Pontianak, the flight data recorder shows the aircraft made an unstable approach, and the crew should have initiated a go-around. Instead, the approach continued, and the aircraft touched down beyond the intended touchdown point. Then the pilot found the thrust reverser hard to operate and the speed brake did not auto-deploy, the NTSC reports. Sensing no deceleration, the crew manually deployed the speed brake after touchdown, and were also able to deploy thrust reversers. That was not sufficient to prevent a runway overrun, and the 737 eventually came to rest 70m beyond the end of the runway. All six crew and 169 passengers were evacuated using the emergency slides, and no injuries were reported. The NTSC criticised Lion Air for failing to follow up on technical log items that indicated a need for maintenance, for not enforcing crew discipline regarding stabilised approach criteria, and for failing to provide any information on changes made following the accident.
Investigators have reported on the fatal TransAsia Airways ATR 72-600 crash into Taipei’s Keelung River on 4 February 2015. Flight GE235 was on a flight to Kinmen from Taipei, and the crash killed 43 of the 60 people on board. Taiwan’s Aviation Safety Council has concluded that the accident was a result of many contributing factors, but ultimately it attributes the disaster to the crew's actions. The TASC says that during the aircraft’s initial climb after takeoff from Taipei Songshan airport, an intermittent fault in the right-hand propeller’s auto-feather unit (AFU) may have initiated the automatic take-off power control system (ATPCS) sequence, resulting in the auto-feathering of that engine. The crew, however, failed to perform the necessary emergency procedures to identify and cope with the results of the failure. This led the pilot flying to retard the power of the perfectly serviceable left-hand engine, ultimately shutting it down. The complete loss of power and inappropriate flight control inputs generated a series of stall warnings, including the activation of the stick shaker and pusher. Still, the crew failed to recognise the loss of power in both engines and to respond accordingly. Transcripts derived from the cockpit voice recorder suggest the crew, speaking in a mixture of English and Mandarin, failed to grasp what had happened. There were three people in the cockpit: two captains and a first officer in the jump seat. “Had the crew prioritised their actions to stabilise the aircraft flight path, correctly identify the propulsion malfunction … then taken actions in accordance with procedure for an engine number two flame-out at take-off, the occurrence could have been prevented,” says the report. Evidence indicated that the AFU failure was probably caused by imperfect or damaged soldering joints in the unit, says the TASC. The crew also failed to reject the take-off when the power-control system was not armed, and the airline had no clearly documented policies and instructions for this. Engine-maker Pratt & Whitney has since issued a modification addressing intermittent failure of the AFU, which is being implemented in all new production engines.
Following investigation into the crash of an Asiana Airlines Airbus A320 (HL7762) at Hiroshima on 14 April 2015 the Japan Transport Safety Bureau (JTSB) has called on the carrier to review its pilot training and re-emphasise compliance with procedures. While attempting to land on runway 28, the aircraft undershot the runway threshold and collided with navigation aids. The aircraft was operating flight OZ162 from Seoul Incheon to Hiroshima, with 81 people on board when the incident occurred in darkness and light rain. The aircraft suffered major damage, and 28 people on-board received minor injuries. Analysis of the cockpit voice recorders showed that, having called “minimum”, the first officer twice told the captain during the approach that he could not see the runway. Only seconds before the touchdown did the captain call to initiate a go-around, but that came too late and the aircraft collided with a localiser antenna. The JTSB says the captain’s decision to continue the approach beyond minimums without runway visual contact did not comply with standards. It noted that the first officer should have called for a go-around when he realised there was no runway visual contact after passing minimums.
Norwegian investigators have praised a rapid crew response that averted the crash of a Wideroe Bombardier de Havilland Dash 8-100 on 2 December 2010 when it was hit by windshear during a night circling approach to Svolvaer airport. The re-opened inquiry into the serious incident has formally attributed the aircraft’s sudden loss of height to a “powerful” microburst. Investigation authority SHT says the captain increased engine power and, with the aircraft on the verge of stalling close to the surface, pushed the control column forward. At some point the first officer instinctively took over the flight controls and pushed the throttles to maximum. Between them, says SHT, the pilots recovered the aircraft at a height of 83ft, remarking that “a marginally longer reaction time or less-resolute use of engine power would probably have resulted in a collision with the sea”. The inquiry had tried to reconcile two differing perspectives on the situation from the captain and the first officer, particularly regarding whether the first officer’s seizing control was necessary, but it has not been able to drawn any firm conclusions over the intervention. The captain might have been exposed to somatogravic illusion as a result of the lack of a visible horizon, but the inquiry found no reasons to indicate that any sensory illusion affected the crew’s handling. SHT says the incident is a reminder of the “vulnerability of aircraft when manoeuvring above featureless terrain at low altitude, particularly in darkness and turbulent air.
Source: FlightGlobal.com
