Aviatraffic B733 at Osh on Nov 22nd 2015, hard landing collapses all gear

Last Update: August 18, 2016 / 14:32:29 GMT/Zulu time

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Incident Facts

Date of incident
Nov 22, 2015

Classification
Accident

Flight number
YK-768

Destination
Osh, Kyrgyzstan

Aircraft Registration
EX-37005

Aircraft Type
Boeing 737-300

ICAO Type Designator
B733

An Aviatraffic Company Kyrgyzstan Boeing 737-300, registration EX-37005 performing flight YK-768 from Bishkek (Kyrgyzstan) to Osh (Kyrgyzstan) with 153 passengers and 6 crew, performed an ILS approach to Osh's runway 12 at about 07:56L (01:56Z) but touched down hard causing all gear to collapse and separate, the aircraft went off the runway and ran over rough terrain, the left hand engine (CFM56) separated and the right hand engine received substantial damage before the aircraft came to a stop about 529 meters past the runway end. 6 occupants received serious, 5 occupants minor injuries. The aircraft sustained substantial damage beyond economic repair.

The aircraft had originally departed Krasnojarsk (Russia) for Osh but diverted to Bishkek due to fog in Osh. After weather was reported improved the crew departed Bishkek for Osh after about 1.5 hours on the ground in Bishkek.

Ground observers reported that the fog became rapidly dense just prior to the aircraft's touch down, visibility deteriorated what appeared to be about 150 meters/500 feet.

Kyrgyzstan's Ministry of Transport stated the aircraft suffered a hard landing resulting in a runway excursion at 07:56L. All gear collapsed, there were a number of injuries. The accident is being investigated.

On Dec 7th 2015 Russia's Civil Aviation Authority reported that the aircraft had conducted an ILS approach to Osh's runway 12, visibility was 50 meters in fog, the runway was wet but with good braking action. The crew went around following a hard touch down and joined a traffic pattern, but during the traffic pattern the crew decided to divert to their alternate meaning to return to Bishkek but soon after received indications of the failure of the right hand engine combined with the failure of two hydraulic systems. The crew shut the right hand engine down and decided to perform an emergency landing in Osh despite weather being below minima. The aircraft touched down very hard about 1400 meters past the threshold of runway 12, the gear collapsed and the aircraft skidded on its belly and engines to a halt 500 meters further down the runway. The occupants evacuated via slides, 10 occupants received injuries of various degrees, 4 received serious injuries. The aircraft received substantial damage to landing gear, engines, fuselage, wings etc.

On Dec 10th 2015 a reader pointed out a misinterpretration of the Russian original of Dec 7th pointing out that the first approach on the accident flight was not aborted due to lack of visual reference but following a hard touch down on the runway that collapsed the gear. A subsequent remark by Rosaviatsia (CAA), not fully comprehended initially, then makes clear, that the subsequent engine failure and dual hydraulic failure were the result of that first hard touch down and damage received.

Osh Airport offers a runway 12/30 of 2614 meters/8600 feet length, runway 12 features an ILS approach (minimum RVR 720 meters/ 2400 feet, DH 67 meters/220 feet for Category C Aircraft).

On Aug 17th 2016 the Interstate Aviation Committee (MAK) released their final report in Russian concluding the probable causes of the accident were:

The accident of the Boeing 737-300 registration EX-37005 occurred as result of rolling out beyond the end of the runway following an emergency landing with two damaged hydraulic systems on single engine with flaps at 15 degrees and damaged main gear struts at dusk in fog with horizontal visibility (RVR) of 50 meters/150 feet and a vertical visibility of 130 feet.

Most likely the accident was caused by a combination of following factors:

- lack of regulations in Kyrgyz Republic and lack of company procedures to forecast the deteriorating weather conditions when performing flights of up to two hours

- formal approach to assess weather by the flight crew upon the decision to conduct the flight although the flight needed to depart from the diversion aerodrome, where the aircraft had diverted to earlier due to weather conditions at Osh preventing a landing. The decision to depart was taken on current weather without taking the weather forecast of deteriorating weather into account.

- lack of skills by the captain to perform a missed approach in actual flight when in adverse weather conditions according to ICAO classification (the captain was certified for Cat IIIa approaches). Flight crew training programmes permit training of holding to acquire and verify minimum weather conditions (including options for a possible go-around) only on certified simulators.

- failure of the crew to comply with the standard operating procedures for a missed approach. Faulty steering inputs by the captain on his own crossing the runway threshold at 38 meters/125 feet above the runway surface within 5 seconds after TOGA had already been initiated disrupted the trajectory of the go-around and resulted in a continued descent. The inactivity of the first officer prevented rectification of the captain's error.

- improper focus of attention when controlling the aircraft at the initiation of a go-around (lack of control of speed when the pitch angle increased)

- the likely exposure of the crew to somatogravic illusion (nose up illusion) due to possible fatigure (at the time of the accident the work time had accumulated to 13 hours), the absence of pitch control could contribute to long term retention of the control wheel.

- insufficiently vigorous nose up input in reaction to ground proximity warning

The MAK reported that the crew operated the scheduled flight YK-768 from Krasnojarsk (Russia) to Osh with a weather forecast suggesting 2500 meters visibility initially but decreasing to 200 meters visibility (30 meters vertically) in fog, only later to increase again to 3000 meters. When the aircraft arrived at Osh tower reported a visibility of 400 meters, vertical visibility 100 feet. The crew therefore decided to divert to Bishkek landing there at 23:20L Nov 21st 2015.

At 23:56L the captain consulted with weather forecasters at Osh, who indicated the weather would be better than METARs and SPECIs suggested and advised the weather would improve to a visibility of 600 meters horizontally and 200 feet vertically at 00:30L. The captain therefore decided to depart at 00:00L Nov 22nd 2015. The aircraft was finally taxiing for departure from Osh at 01:04L, during taxi the actual weather report from Osh was received and indicated visibility of 200-800 meters horizontally and 200 feet vertically sometimes reducing to 100 feet.

Following departure at 01:08L Air Traffic Control advised at 01:18L visibility at Osh had improved to 1700meters horizontally and 200 feet verticaly.

While descending to FL070 at Osh at 01:38L ATC advised visibility was 900 meters horizontally and 100 feet vertically and queried whether the aircraft would commence the approach. The crew continued the approach.

At 01:43L ATC advised the visibility had reduced to 500 meters horizontally and 100 feet vertically.

At 01:44L the crew advised they were going around, the aircraft however collided with the runway within the touch down zone at +3.96G. While climbing out the crew queried weather and subsequently decided to return to Bishkek. The aircraft climbed to FL150, the crew intended to climb higher. However, as result of the impact on the runway two hydraulic systems had failed and the right hand engine showed increasing problems including decreasing oil pressure and rising EGT. The crew assessed their options to divert to Bishkek and decided to land at Osh despite the weather conditions present. The right hand engine was shut down and the aircraft returned to Osh for an emergency landing, touched down about 1063 meters past the runway threshold and overran the end of the runway by 529 meters.

The MAK reported 6 passengers received "moderate" injuries during the landing, 5 passengers received minor injuries during the landing.

Metars:
CFO 220400Z VRB01MPS 0150 R12/0150 FG VV001 06/05 Q1025 R12/19//65 NOSIG
UCFO 220330Z VRB01MPS 0050 R12/0050 FG VV001 06/05 Q1025 R12/19//65 NOSIG
UCFO 220300Z 00000MPS 0050 R12/0050 FG VV001 05/05 Q1025 R12/19//65 NOSIG
UCFO 220230Z 29001MPS 0050 R12/0050 FG VV001 05/04 Q1025 R12/19//65 NOSIG
UCFO 220200Z 27003MPS 0050 R12/0050 FG VV001 05/04 Q1025 R12/19//65 NOSIG
UCFO 220130Z 25001MPS 0750 R12/1800 FG VV002 06/05 Q1025 R12/19//65 TEMPO 0300 FG VV001
UCFO 220100Z 23002MPS 0250 R12/0800 FG VV002 06/05 Q1025 R12/19//65 TEMPO 0100 FG VV001
UCFO 220030Z 26002MPS 0600 R12/1600 FG VV002 06/05 Q1024 R12/19//65 TEMPO 0100 FG VV001
UCFO 220000Z VRB01MPS 0150 R12/0500 -DZ FG VV001 06/05 Q1024 R12/19//65 TEMPO 0100 FG VV001
UCFO 212330Z 36002MPS 0250 R12/0800 -DZ FG VV001 06/05 Q1023 R12/19//65 TEMPO 0100 FG VV001
UCFO 212300Z 36003MPS 0100 R12/0400 -DZ FG VV001 06/05 Q1023 R12/19//60 TEMPO 0100 FG VV001
UCFO 212230Z 03003MPS 0250 R12/0800 -DZ FG VV001 06/05 Q1023 R12/19//60 TEMPO 0200 FG VV001
UCFO 212200Z 02002MPS 0450 R12/1400 -DZ FG VV001 06/05 Q1023 R12/19//60 TEMPO 0200 FG VV001
UCFO 212130Z 06002MPS 0700 R12/1700 -DZ FG OVC002 06/05 Q1023 R12/19//60 TEMPO 0300 FG VV002
UCFO 212100Z 05001MPS 1000 R12/P2000 -DZ BR OVC005 06/05 Q1023 R12/19//60 TEMPO 0300 FG VV002
UCFO 212030Z 08001MPS 0600 R12/1500N -DZ FG VV003 06/05 Q1023 R12/19//60 TEMPO 0300 FG VV002
UCFO 212000Z 34001MPS 0500 R12/1400 -RA FG VV003 06/05 Q1023 R12/19//60 TEMPO 0300 FG VV002
Incident Facts

Date of incident
Nov 22, 2015

Classification
Accident

Flight number
YK-768

Destination
Osh, Kyrgyzstan

Aircraft Registration
EX-37005

Aircraft Type
Boeing 737-300

ICAO Type Designator
B733

This article is published under license from Avherald.com. © of text by Avherald.com.
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