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UTAir B735 at Moscow on Oct 13th 2017, loss of control recovered

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One Winged Junkie
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UTAir B735 at Moscow on Oct 13th 2017, loss of control recovered

Post by One Winged Junkie » Tue Nov 07, 2017 11:44 am

https://www.avherald.com/h?article=4b01e302&opt=0



A UTAir Boeing 737-500, registration VQ-BJP performing flight UT-588 from Krasnodar to Moscow Vnukovo (Russia), was on final approach to Vnukovo's runway 06 at 09:17L (06:17Z) descending through about 1950 feet MSL (transponder altitude 2250 feet corrected for QNH) at 152 knots over ground when the crew initiated a go-around about 5.3nm before the runway threshold (about 2.2 degrees glidepath). While climbing the airspeed rapidly dropped reaching 100 knots over ground while descending through 2700 feet MSL, the right wing dropped rapidly. The aircraft stabilized again on a track about 65 degrees left off the final track at 3800 feet MSL and 194 knots over ground about a minute later. The crew reported they were low on fuel, they had gone around due to an unstabilized approach, then positioned for another approach to runway 06 and landed without further incident about 18 minutes after the upset.

The aircraft is still on the ground in Moscow 273 hours (almost 11.5 days) later.

Unverifyable Russian aviation sources claim on a Russian pilot forum that the flight data recorder shows the upset began when the pitch angle reached 45 degrees nose up, a right bank angle of 33 degrees developed followed by 34 degrees left bank, the pitch angle reduced to 30 degrees nose up, the aircraft rolled rapidly to 96 degrees right bank consistent with the right hand wing having stalled with the airspeed having reduced to 60 KIAS, pitch dropped to 14 degrees nose down, aircraft rolled to a left bank 45 degrees, speed recovered to 150 KIAS and the aircraft recovered from stall after losing a total of 1000 feet of height.

On Oct 25th 2017 a graphics claiming to be produced off the FDR of the aircraft was uploaded to a Facebook Account from another unverifyable source (unrelated to the first source), see below.

A passenger praised the crew stating the crew landed professionally despite the complex weather conditions.

There has been no official statement so far, neither Rostransnador (Russia's Transport Ministry), Rosaviatsia (Russia's Civil Aviation Authority), MAK (Interstate Accident Investigation) nor any of the Russian Transport Prosecutors have yet reported on the occurrence.

Data transmitted by the aircraft's transponder support a major upset during a go around iniated at about 06:17Z at 2250 feet (not corrected for QNH) descending at 152 knots over ground, at 06:18Z the aircraft was at 3025 feet (not corrected for QNH) descending at 100 knots at 06:18Z and at 4150 feet (not corrected for QNH) climbing at 194 knots over ground at 06:19z.

On Nov 1st 2017 The Aviation Herald received information suggesting the occurrence has been rated a serious incident and is being investigated by the Civil Aviation Authority (Rosaviatsia). The (originally Russian) statement reads in part: "In the course of flight data analysis it was recorded that the aircraft has been hit in a complex spatial situation accompanied by a significant loss of speed and altitude. The achieved pitch and roll angles are not characteristic for normal operation." The information further says, that the Interstate Aviation Committee (MAK) sees parallels to the crashes in Perm, see Crash: Aeroflot-Nord B735 at Perm on Sep 14th 2008, impacted ground while on approach to Perm, Kazan, see Crash: Tatarstan B735 at Kazan on Nov 17th 2013, crashed on go-around, and Rostov, see Crash: Flydubai B738 at Rostov on Don on Mar 19th 2016, lost height on go around after stabilizer moved nose down following holding for 2 hours.

On Nov 1st 2017 Rosaviatsia (Russia's CAA) reported the aircraft intercepted localizer and glideslope on autopilot and autothrottle. While intercepting the glideslope the crew selected the flaps to 30 degrees. The autopilot went offline, autothrottle remained connected and increased thrust to about 95%, which caused the aircraft to pitch up due the engines underneath the wings producing a pitch up moment. The crew attempted to counteract by pushing the yoke forward and attempted to reduce engine thrust, however, with autothrottle still engaged the engines still remained in high thrust causing the aircraft to pitch up to 45 degrees nose up, the speed decreased to below 100 knots (with minimum safe speed at 114 knots), the aircraft began to roll left and right reaching a right bank angle of 95 degrees - this is called "complex spatial situation". The crew continued to push the nose down, at 750 meters above ground the nose finally dropped through the horizont, the aircraft began to descend sharply and the airspeed increased, the crew managed to regain control of the aircraft at about 350 meters above ground. The aircraft then climbed, joined another approach and landed without further incident. The occurrence was rated a serious incident and is being investigated.

The elevation of the threshold of runway 06 is 194.1 meters/637 feet MSL.

Metars:
UUWW 130730Z 17002MPS 120V200 4300 -DZ BR OVC003 10/09 Q1001 R06/290050 NOSIG=
UUWW 130700Z 16002MPS 120V200 4400 BR OVC001 09/09 Q1001 R06/290050 NOSIG RMK QBB050=
UUWW 130630Z 16002MPS 130V200 4100 BR OVC002 09/08 Q1001 R06/290050 NOSIG=
UUWW 130600Z 17003MPS 2100 R24/1600U BR OVC001 09/08 Q1002 R24/290050 TEMPO 0400 FG RMK QBB050=
UUWW 130530Z 16003MPS 1400 1200SE R24/1200U -DZ BR OVC001 09/08 Q1002 R24/290050 TEMPO 0400 FG RMK QBB040=
UUWW 130500Z 17003MPS 1800 1300SE R24/1300N BR OVC001 08/08 Q1002 R24/290050 TEMPO 0400 FG RMK QBB040=
UUWW 130430Z 16003MPS 1300 1200W R24/1300N BR OVC001 08/07 Q1002 R24/290050 TEMPO 0400 FG RMK QBB040=
UUWW 130400Z 16004MPS 2000 R24/1600U BR OVC001 08/07 Q1002 R24/290050 TEMPO 1000 -SHRA BR BKN015CB RMK QBB040=
UUWW 130330Z 16004MPS 3500 -SHRA BR BKN001 BKN///CB 08/07 Q1003 R24/290050 TEMPO 1000 -SHRA BR BKN015CB RMK QBB050=
UUWW 130300Z 16003MPS 4300 BR OVC001 08/07 Q1003 R24/290050 TEMPO 1000 -SHRA BR BKN015CB RMK QBB050=
Attachments
Map and trajectory Graphics AVH Google Earth.jpg
Map and trajectory Graphics AVH Google Earth.jpg (97.58 KiB) Viewed 718 times
Detail of supposed FDR data.jpg
Detail of supposed FDR data.jpg (122.09 KiB) Viewed 718 times
utair_b735_vq-bjp_moscow_171013_1.jpg
Supposed FDR data:
utair_b735_vq-bjp_moscow_171013_1.jpg (72.49 KiB) Viewed 718 times