Aeroflot Flight 5484

Aeroflot

Company type	State-owned airline
Industry	Aviation
Founded	1923
Headquarters	Moscow , Soviet Union
Products	Passenger and cargo air transport services

Aeroflot Flight 5484 Overview

Aeroflot Flight 5484 was a domestic passenger service operating between Odesa in Soviet Ukraine and Kazan, the capital city of Tatarstan, with an intermediate stop at Kyiv. On 29 August 1979, the aircraft lost control and subsequently disintegrated mid-flight over the Tambov Oblast, resulting in the deaths of all 63 individuals on board. This incident stands as the most fatal accident involving a Tu-124 aircraft. Following this tragedy, regular passenger operations utilizing the Tu-124 were discontinued permanently, although the model continued to be employed by Soviet military forces.

Aircraft and Crew Details

The airplane involved was a Tupolev Tu-124V equipped with two Soloviev D-20P engines, bearing the registration CCCP-45038, and operated by the Privolzhsk Civil Aviation Directorate under Aeroflot. Prior to the accident, the aircraft had accumulated 23,232 flight hours alongside 18,369 pressurization cycles. The flight crew comprised five members: a captain, co-pilot, navigator, flight engineer, and a single flight attendant.

Synopsis

Flight 5484 departed from its layover at Kyiv Boryspil Airport on August 28 at 23:21 MSK - Moscow Time (22:21 local time)Template:Dubious, carrying five crew members and 58 passengers, among them five children. The weather was clear with visibility estimated between 10 to 20 km (6.2 to 12.4 mi; 5.4 to 10.8 nmi). After takeoff, the aircraft ascended to a cruising altitude of 9,000 metres (30,000 ft) and maintained a velocity of approximately 525–530 km/h (326–329 mph; 283–286 kn). At 00:23 MSK, the flight established communication with Penza air traffic control upon entering their airspace. This marked the final contact with air traffic controllers.

At 00:24:35, while flying at a heading of 65° and a speed of 530 km/h (330 mph; 290 kn), the flaps were extended for reasons that remain unclear. Shortly thereafter, the crew observed an unexpected loss of altitude and disengaged the autopilot at 00:24:43. Despite their efforts, the flaps did not retract, and their extended position caused a rapid descent. The pilots attempted to level the aircraft by pulling back on the control column; this briefly stabilized the plane before it began to roll. At 00:24:52, the force applied to the control column diminished, coinciding with the flaps fully extending to 30°, which plunged the aircraft into a steep dive that rapidly surpassed its maximum safe speed of 590 km/h (370 mph; 320 kn).

By 00:25:13 MSK, less than one minute after flap extension, the aircraft had descended to an altitude of 6,000 metres (20,000 ft), accelerating to 660 km/h (360 kn; 410 mph) while descending at a rate of 36 m/s (7,100 ft/min). At this point, the inboard flap detached from the right wing, followed by the loss of outboard flaps. This damage induced a spin at a rotation rate of 45°/s (7.5 rpm). By 00:26, the compromised aircraft had dropped to 3,000 metres (9,800 ft), reached speeds near 860 km/h (460 kn; 530 mph), and descended at approximately 280 metres per second (55,000 ft/min). These conditions imposed a load factor of 5g, causing the left wing to separate and resulting in mid-air disintegration of the fuselage.

The crash debris was discovered at 07:40 MSK - Moscow Time near the town of Inokovka, situated on the floodplains of the Vorona River in Tambov Oblast within the Russian SFSR. Wreckage was scattered over an area measuring approximately 10,750 by 1,650 metres (35,270 by 5,410 ft), with fuselage fragments concentrated within a zone roughly 10,000 by 1,200 metres (32,800 by 3,900 ft) in size. All 63 individuals aboard perished in this accident, which stands as the deadliest incident involving a Tu-124 aircraft.

Conclusions

The investigation was unable to determine why the flaps deployed during cruise altitude due to missing key components of the flap control system from recovered wreckage. While no conclusive explanation was reached, investigators proposed several hypotheses regarding this unexpected flap extension:

1. It is conceivable that the captain inadvertently activated the flap release switch without awareness. Testing confirmed that accidental engagement of this switch was possible despite safety locks.
2. An electrical fault within the flap control circuitry may have caused unintended activation; however, investigators doubted rapid triggering by stray signals and noted such faults would likely evade routine maintenance detection. To evaluate this theory, six Tu-124s with identical flap systems underwent testing, all confirming proper functionality.

The rationale behind the crew reducing their input on the control column at 00:25:13—leading to an abrupt descent—is also unclear. Potential explanations include:

1. The crew may have been deceived by variometer readings indicating an ascent rate between 15 and 20 m/s (49 and 66 ft/s), whereas in reality, descent rates were closer to 40–45 m/s (130–150 ft/s);
2. Attention might have shifted to other cockpit operations such as adjusting engine thrust, manipulating flap settings, or verifying spoiler positions;
3. Excessive forces on the control column due to overload and overspeed conditions;
4. The high rate of descent itself may have limited crew ability to maintain sufficient control input;
5. Or a combination thereof contributing simultaneously to loss of effective control.

Aftermath

Although the Tupolev Tu-124 was removed from routine commercial flights within the USSR, it continued to serve in a military capacity. Modifications were made to the flap release switch's design and location to reduce the risk of unintentional flap deployment.