CASE FILE (#A6-FZ981): FlyDubai Flight 981 (FZ981/FDB981)
DATE: March 19th, 2016
TIME: 03.41 (CVR and FDR Located & Recovered)
AIRCRAFT: Boeing 737-800
ROUTE: Dubai (UAE) to Rostov-on-Don (Russia)
CRASH STATUS: Ongoing
INVESTIGATION STATUS: Interim Report (here)
AIRCRAFT FATALITIES: 62 (55 passengers & 7 crew)
GROUND FATALITIES: 0
The crash was Flydubai's first fatal incident in its eight-year history.
First approach and hold
After a four-hour flight, at 01:39 local time, the aircraft made its first landing attempt, but had to abort it at 01:42 at 1,725 feet (526 m), 6.7 kilometres (4.2 mi) short of the runway, due to poor weather conditions. Ten minutes before this attempt, two other flights landed successfully at Rostov-on-Don from the first attempt: S7 Airlines Flight 1159 (at 01:23), and Ural Airlines Flight 2758 (at 01:28).
Flight 981 went into a holding pattern near the airport, awaiting better weather conditions, for the next two hours. It maintained 8,000 feet (2,400 m) for the first 30 minutes of the hold and then climbed to 15,000 feet (4,600 m) feet. Soon after Flight 981's first aborted landing, Aeroflot Flight 1166 made three unsuccessful attempts to land at Rostov-on-Don (at 01:54, 02:07 and 02:17) and at 02:20 diverted to nearby Krasnodar International where it landed successfully at 02:59.
Second approach and crash
At 03:28, the crew of Flydubai Flight 981 started the second attempt to land on runway 22. According to ATC communications published online, pilots reported to ATC that in case they would need to make another go-around, they would climb to flight level 80—approximately 8,000 feet (2,400 m). At 03:36 the aircraft intercepted the runway 22 localizer at 10 nautical miles (19 km) from the runway. The crew confirmed it to ATC and continued the descent.
At 03:40:54, when the aircraft descended to 480 meters (1,570 ft) with a speed of 243 km/h and was about 5.5 kilometres (3.4 mi) from the runway threshold, the crew decided to abort the landing. They reported their intention to ATC with "Going around, Sky Dubai 981". ATC advised Flight 981 to switch to another air traffic controller ("Sky Dubai 981, contact Rostov Radar on 121.2"). Flight 981 acknowledged this with "121.2, bye-bye", which was their final transmission. The aircraft increased its speed and within 43 seconds climbed to 1,200 meters (3,900 ft) with a speed of about 343 km/h.
Starting at 03:41:37 the aircraft's altitude rapidly decreased and it hit the ground.
At 03:42, the air traffic controller (ATC) of the airport alerted the local emergency services about the crash. The aircraft impacted the ground immediately east of the approach end of Runway 22. A CCTV video, uploaded online after the crash, shows an aircraft making a steep descent into the ground, followed by an explosion.
According to a source from the rescue team, the small radius of the expansion of debris and the small size of the debris parts, points out that the speed of the fall was more than 400 km/h; as even the aircraft's magnesium alloy wheel rims, its most solid part, were shattered. This speed assessment matches the Flightradar24 data. According to the same source, the plane struck the ground approximately at a 60–degree angle.[ According Rostov-on-Don branch of the Ministry of Emergency Situations, the wing of the aircraft first touched the ground in the crash.
Flight 981 carried fuel for 8.5 hours of flight. It had been airborne for 6 hours until the crash.
On 20 April a first interim report was published by the IAC. Findings:
Both approaches were conducted in flight director mode, with the autopilot and autothrottles disengaged. There were no significant heading or altitude deviations from the prescribed approach course.
At 22:42, while conducting the first approach, the crew elected to abort and initiate a go-around procedure, in response to an alert from the on-board windshear warning system. They climbed to FL 50 (1500m) and then to FL 80 (2450m) to hold. While in that holding pattern, the crew reported moderate icing and requested further climb to FL 150 (4550m), where they held until descending again for a second approach attempt.
During the second approach, the crew again aborted and initiated another go around at a height of 220 meters and a distance of 4.5 km from the runway threshold. The vertical speed during that second go-around went as high as 20 mps, while engine thrust was set at the maximum TOGA limit of 101 – 102% (N1).
The second go-around decision was probably provoked by a sudden 20-knot increase of indicated speed to as much as 176 knots within 3 seconds, which could have been an indication of a windshear.
During the second go-around, flaps were set at 15° and the landing gear was retracted. At 1900 ft (approx. 600m) the nose up pitch angle reached 18°. The pilot flying pushed the control column forward, causing the vertical acceleration to decrease, while the forward speed increased to over 200 knots, which caused an automatic retraction of flaps from 15° to 10°.
A short-term reduction of engine thrust followed within 3 seconds, resulting in decreasing speed which triggered an automatic extension of the flaps back to 15°. The crew then intervened, again setting maximum TOGA thrust, which caused another automatic flaps retraction, back to 10°, where they remained until the impact.
The pilot flying then pulled back on the control column, which increased the vertical speed to as much as 16 mps.
At a height of 900m, there was a simultaneous control column nose down input and a trimming of the horizonal stabilizer to a nose down position, from -2,5 deg (6,5 units) to +2,5 deg (1,5 units). The FDR recorded that nose down stabilizer trimming, from the stabilizer trim switchs on the control wheel, lasting 12 seconds. The CVR also recorded the specific noise of rotation of the trim wheels, located on both sides of the central pedestal.
The result was that after the aircraft climbed to about 1000m, it then began a rapid descent with negative vertical acceleration of -1g. The subsequent crew attempts to recover were not sufficient to avoid an impact with the ground.
A 00:41:49, the aircraft hit the runway approximately 120m from the threshold with a speed of over 600 kmph and a nose down pitch exceeding 50 degrees. The impact totally destroyed the aircraft, instantly killing all on board.