Aeroflot A313 near Novosibirsk on Mar 23rd 1994, captain's son in left seat, aircraft was not recovered

Last Update: March 9, 2021 / 08:47:36 GMT/Zulu time

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Photo of Aeroflot F-OGQS, Airbus A310-300 — Aeroflot F-OGQS, Airbus A310-300 (Photo credit: Deanster1983 who's mostly off / Flickr / License: CC by-nd)

Incident Facts

Date of incident
Mar 23, 1994

Classification
Report

Airline
Aeroflot

Flight number
SU-593

Departure
Moscow Sheremetyevo, Russia

Destination
Hong Kong, Hong Kong

Aircraft Registration
F-OGQS

Aircraft Type
Airbus A310-300

ICAO Type Designator
A313

An Aeroflot Airbus A310-300, registration F-OGQS performing flight SU-593 from Moscow Sheremetyevo (Russia) to Hong Kong (Hong Kong) with 63 passengers and 12 crew, was enroute at 10100 meters (FL331) about 210nm southeast of Novosibirsk (Russia) when the captain first permitted his daugther into the left hand seat and subsequently his son (16) into the left hand seat with the captain being pilot flying and the autopilot engaged. The boy inadvertently caused the autopilot's roll channel to disconnect, the autopilot as result disconnected (however, the pitch channel remained active attempting to maintain altitude), the aircraft rolled into a steep bank and entered a near vertical dive. The first officer managed to level the wings and pull the aircraft out of the dive temporarily, the aircraft however entered a stall and a spin and could not be recovered anymore until impact with the ground. All occupants perished in the crash.

The Department of Transport of the Russian Federation released their final report in Russian some time in the past concluding the probable causes the crash were:

The aircraft entered a stall and spin and impacted ground as result of following factors:

- The captain's decision to permit an unqualified and non authorized person, his son, to occupy his seat and intervene in the operation of the aircraft.

- Demonstration of maneouvers that were not planned or anticipated in the flight situation with the captain operating the autopilot while not in his seat

- Forces onto the roll controls applied by the son and first officer that interfered with the autopilot's roll channel (and are not recommended by the FCOM) overriding the autopilot and disconnecting the autopilot's aileron control.

- The first officer as well as the captain did not detect the fact, that the autopilot's roll channel had disconnected, probably due to lack of an according warning in the instrumentation. The provision of such a signal could have enabled the crew to detect the disengagement in a timely manner.

- Both flight crew may have been unaware of the peculiarities of this disconnect function and the actions to be taken in such an event due to lack of such information in the FCOM and crew training materials.

- It was difficult for the first officer to detect the disengagement of the roll channel by feel, either because of little forces on the control column or because he mistook the forces on the control column as actions by the son of the captain. The captain was out of his position and distracted by his daughter.

- A slight unintentional movement of the control wheel caused the autopilot's roll channel to disconnect completely, a roll to the right developed.

- Both flight crew failed to detect the excessive (beyond operational limits) right bank angle and were late in re-entering the control loop with their attention initially focussed to determine why the aircraft had turned right, they both believed the aircraft had entered a holding. A strong warning indicating the excessive bank angle could have alerted the crew and enabled them to detect the excessive bank earlier.

- The aircraft was subject to buffeting and high angles of attack as the autopilot, the pitch channel of which had remained active, attempted to maintain altitude despite the roll channel having disconnected.

- Inappropriate actions by the first officer, who failed to disconnect the autopilot and to push the control column forward when the aircraft entered an unusual attitude (high angle of attack and high pitch)

- These actions caused the aircraft to stall and spin.

The investigation analysed that the captain, pilot flying, had invited his daughter into the left hand seat earlier in the flight without handing controls to the first officer, thus he remained officially in control of the aircraft. The daughter remained 7.5 minutes in the left hand seat while performing several control activities, both daughter and captain were engaged in continued discussions. Subsequently the captain invited his son into the left hand seat. While the captain again demonstrated some maneouver to his son, varying control forces were registered at the aileron controls which exceeded the limit triggering the override function, the roll channel of the autopilot disconnected. The control forces decreased again but remained applied with the control wheel still turned about 3-5 degrees to the right. When the aircraft rolled through 45 degrees (the operational limit) right the son realized something was not correct and alerted his father, who was just engaged in a discussion with his daughter, stating that the aircraft was turning by itself. Father and first officer concluded the aircraft was entering a holding area. When the aircraft rolled through more than 50 degrees right bank, buffeting occurred at more than +1.6G, the aircraft pitched up from about 4.5 degreese nose up to 10 degrees nose up, While the son attempted to hold the control column in a neutral position, on instruction by his father to "hold it", the first officer who correctly understood the captain's instruction to counter the roll attempted to roll the aircraft left. The aircraft deviated from the altitude, the altitude warning sounded, the autopilot increased nose up elevator input. The aircraft entered a stall, both flight crew were considered to have lost spatial orientation at that point. The aircraft rolled to about 80-90 degrees to the right, entered a nose down attitude of about 50 degrees nose down with the vertical acceleration reaching +2G. Attempts to deflect the elevator nose up caused the autopilot to entirely disconnect, the wailer sounded and was not disengaged until impact. After the autopilot disconnected the aircraft's anti-stall protection intervened and pushed the nose down, the first officer regained lateral orientation and applied left control inputs rolling the wings level. However, as the engines were still operating at high thrust the aircraft went into overspeed, nose up inputs occurred which resulted in vertical acceleration of +4.6-+4.7G exceeding the structural limit of the aircraft. The aircraft pitched up, the airspeed reduced to about 100-120 KIAS and stalled again. The ailerons were applied to the left causing the aircraft to roll sharply right (aileron reversal). When the rudder was deflected to about 8 degrees left the aircraft entered a classic spin from which it was not recovered.

A reader made us later aware, that an English version of this report is available in the ICAO Libraries, we thus downloaded that version and make it available here, too.