Aeroflot Flight H-75 Explained

Aeroflot Flight 75
Occurrence Type:Accident
Summary:Icing, loss of control
Site:near Mukachevo, Zakarpattia Oblast (USSR, USSR)
Aircraft Type:Antonov An-24B
Operator:Aeroflot (Ukrainian Civil Aviation Directorate, Kiev Aviation Enterprise)
Tail Number:CCCP-46357
Origin:Zhuliany Airport, Kiev
Stopover0:Ivano-Frankivsk Airport
Destination:Mukachevo Air Base
Passengers:18
Crew:6
Fatalities:24
Survivors:0

The Aeroflot Flight H-75 was an aviation accident involving an Antonov An-24B aircraft operated by the Kiev United Aviation Squadron (Aeroflot), which occurred on Sunday, January 6, 1974, near Mukachevo, resulting in the deaths of all 24 people on board.[1] [2]

Aircraft

The An-24B with registration CCCP-46357 (serial number 07305807, manufacturing number 058-07) was manufactured by the Kiev Aviation Plant on January 23, 1970. The airliner was delivered to the Ministry of Civil Aviation of the USSR, which transferred it to the Kiev United Aviation Squadron (86th Flight Squadron) of the Ukrainian Civil Aviation Directorate on February 2. The aircraft had accumulated a total of 9,280 flight hours and 8,083 takeoff-landing cycles.[3]

Crew

Accident

The aircraft was scheduled to operate domestic flight N-75 from Kiev to Ivano-Frankivsk to Uzhhorod. However, on that day, the Uzhhorod Airport was unable to receive aircraft due to its runway being in unsatisfactory technical condition, leading planes to land at the nearby military Mukachevo Airfield. Mukachevo was also closed due to poor weather conditions, causing flight N-75 to be delayed at Ivano-Frankivsk Airport.[4]

After the weather improved, the forecast along the route included numerous stratocumulus clouds with a base of 100–150 meters and a top of 500–1000 meters, visibility of 1000–1500 meters, mist, and icing in clouds. At 14:51, flight N-75 departed from Ivano-Frankivsk and after reaching altitude at 14:57, it leveled off at an altitude of 3,000 meters. However, at 15:04, the controller in Lviv instructed the crew to descend to an altitude of 2,400 meters due to air traffic conditions. At 15:09, the crew reported passing the waypoint Vysoke at 2,400 meters and subsequently switched communication to the Mukachevo airfield controller, continuing the flight at approximately 400 km/h.

At around 15:14, four minutes before reaching the waypoint Serednie, the crew began descending at a vertical speed of 7.5 m/s to an altitude of 2,100 meters, then reduced speed to 300 km/h. The crew continued descending to 400 meters, likely extending the landing gear in advance. During the descent, the An-24 entered cloud cover, emerging six minutes later. The sky over Mukachevo was covered with stratocumulus clouds at 120 meters, the air temperature was −1°C, there was calm, mist, and visibility was 1,100 meters.

The controller indicated that the landing would be on a magnetic course of 22°. Following this, as per his instruction, the crew turned to the opposite landing course and began executing the third turn 11 kilometers from the runway. As the aircraft proceeded to the fourth turn at 310 km/h, the pilots extended the flaps to the landing position, after which the speed dropped by 45 km/h over 50 seconds. As a result, the engine power was increased at 260 km/h. When the aircraft completed the fourth turn at around 15:24 and aligned with the landing course, the engine power was reduced, and the flaps were fully extended. Sixteen seconds later, the speed decreased to 240 km/h, prompting the crew to increase engine power again. The speed initially dropped to 220 km/h, then increased to 230 km/h, leading to another slight reduction in engine power.

The aircraft was 200 meters above the ground when the pilots, attempting to level the aircraft, first pushed the elevator down. The aircraft pitched steeply downward, prompting the elevator to be pulled up to raise the nose. However, the airliner rolled to the left up to 30°. The pilots tried to recover, but at 15:25, the inverted An-24, descending at a 70° angle, severed wires on wooden poles 100 meters past the outer marker, then crashed into a dirt road on a field, completely destroyed, and burned. All 24 people on board perished.

Causes

After examining the flight data and inspecting the aircraft wreckage, the technical commission concluded that the anti-icing system had not been activated.

The cause of the accident was a loss of longitudinal control on the final approach due to a possible insufficient margin of attack angles of the horizontal stabilizer in the landing configuration with flaps extended to 38° in light icing conditions.
Contributing factors:

  1. Lack of warning information to the crew about the stabilizer reaching angles close to critical.
  2. Non-activation or premature deactivation of the wing and stabilizer anti-icing system in the presence of light icing (2-3 mm).
  3. Absence of reliable onboard information about the presence of aircraft icing.

In the final report, representatives of the Ministry of Aircraft Industry recorded the following statement:

External links

Notes and References

  1. Web site: Різдвяна трагедія: майже півстоліття тому під Мукачевом розбився пасажирський АН-24. Голос Карпат. 2018-10-03. 2018-11-27. https://web.archive.org/web/20181127022417/https://goloskarpat.info/society/5a509f0ad3199/. live.
  2. Якубович Н. В. Неизвестный Антонов М.: Яуза ; Эксмо, 2009. — 384 с. — (Война и мы. Авиаконструкторы). — Тираж 5 000 экз. — ISBN 978-5-699-32738-6 стр. 35
  3. Web site: Антонов Ан-24Б CCCP-46357 а/к Аэрофлот - МГА СССР - карточка борта. russianplanes.net. ru. 2015-03-31. 2015-04-02. https://web.archive.org/web/20150402184418/http://russianplanes.net/reginfo/61136. live.
  4. Web site: Катастрофа Ан-24Б Украинского УГА близ Мукачево (борт CCCP-46357), 06 января 1974 года.. airdisaster.ru. 2013-05-04. https://web.archive.org/web/20130122065909/http://airdisaster.ru/database.php?id=109. 2013-01-22. live.