Yesterday, Russia’s Interstate Aviation Committee (IAC, or MAK in Russian) released their interim report on their investigation of the crash of flight Aeroflot SU1492 on May 5th, 2019. Happening on a stormy day in Moscow, the crash took the lives of 40 passengers and one crew member.
The report, written in English, “contains the actual information, currently received by the investigation team, conducting the accident investigation…as well as the results of the data decoding of the onboard and ground data recorders, video records, results of the examinations.” The report appears to be written by non-native English speakers. As such, there are grammatical errors that we have had to interpret.
An active thunderstorm area
The report is extensive and goes through every action of the flight – from crew arrival and passenger boarding. However, in this article we will attempt to highlight the key findings of the report:
According to the “Vnukovo7 Doppler weather radar”, the aircraft was flying through an active thunderstorm area. The crew did not request clearance to avoid the area. However, “other aircraft following and preceding the SU1492” did in fact request clearance.
Between 15:07:30 to 15:07:33, the following conversation between crew members took place:
Pilot in Command: “We are going to get shaken”
First Officer: “Damn it.”
Pilot in Command: “Nothing to worry about”.
The full report includes a chart of the various flights that made a request to avoid the area. This includes three flights before and 10 flights following Aeroflot 1492. After a short discussion with the First Officer, the Pilot in Charge made the decision to return to Sheremetyevo airport.
As the crew made its return to Sheremetyevo airport, the report states that it performed neither the before-landing briefing nor the “APPROACH” checklist. Proceeding further, a “WINDSHEAR” warning was triggered, generated by the crew alert system based on wind shear data of the weather radar.
This alert is accompanied by the voice message “GO-AROUND, WINDSHEAR AHEAD”. The crew had no discussion after hearing this warning. In fact, the triggering of this warning on approach states that the crew must initiate the go-around procedure.
As the pilot had earlier switched the aircraft to “DIRECT MODE” (manual control), the automatic deployment of the speedbrakes (spoilers) was not engaged. The crew did not deploy manual speedbrakes.
After touching down, the aircraft bounced up to a height of no more than two meters. Occurring 2.2 seconds after the first touchdown, the second bounce reached the height of 5-6 meters.
Following this, thrust levers were set to “Takeoff” mode and the sidestick was pulled to the maximum retard position. The report interprets these actions as an attempt to perform a go-around. However, engine thrust did not increase. This is because the thrust reverser system was engaged previously.
Finally, with a force of at least five Gs, the third touchdown partially destroyed the main landing gears. Additionally, aircraft structural disintegration, fuel spillage and fire occurred.
The IAC reports that upon examination of the fuselage, typical traces of “lightning impact” appear on the following parts of the plane:
- Right ice detector
- Upper front part of the fuselage
- Right angle of attack sensor
- Right temperature probe
#Aeroflot #SU95 @ #Moscow
On May 6th 2019 Roaviatsia (Russia’s CAA) reported a #LightningStrike at 2100meters/6900ft MSL resulted in the failure of the radios and other equipment including the autopilot and the fire broke out following the #fourth touchdown=
(via #AviationHerald) pic.twitter.com/FGlaJZOk98
— Emilio Simone (@EmilioSimone1) May 6, 2019
From the findings of the preliminary report, it appears that the pilots made several decisions that did not align with standard operating procedures. Most notable is the decision to fly through the storm.
The following aspects of the incident are under analysis and will be part of the final report:
When the Final Report finally comes out, we will have another summary of the findings.