Aeroflot Flight H-75

Kiev United Aviation Squadron

Industry	Aviation
Founded	February 2, 1970 (1970-02-02)
Headquarters	Kiev , USSR
Parent	Aeroflot

Template:Infobox aircraft occurrence

Aeroflot Flight H-75 involved an Antonov An-24B operated by the Kiev United Aviation Squadron under Aeroflot. On 6 January 1974, the aircraft crashed close to Mukachevo, resulting in the loss of all 24 individuals aboard.

Aircraft

The aircraft involved, an An-24B bearing registration CCCP-46357 (serial number 07305807, production number 058-07), was manufactured at the Kiev Aviation Plant on 23 January 1970. It was handed over to the Ministry of Civil Aviation of the USSR and subsequently assigned to the Kiev United Aviation Squadron (86th Flight Squadron) of the Ukrainian Civil Aviation Directorate on 2 February. Prior to the accident, the airplane had logged a total of 9,280 flight hours and completed 8,083 takeoff and landing cycles.

Crew

• Captain: Komissarov Pavel Dmitrievich
• First Officer: Yevnitsky Gennady Vasilievich
• Navigator: Grysyuk Alexander Petrovich
• Flight Engineer: Borovkov Viktor Pavlovich
• Flight Attendant: Slepukhina Zinaida N.
• Escorting Police Officer: Lazaretz Oleg Vasilievich

Accident

Flight N-75 was planned as a domestic route from Kiev to Ivano-Frankivsk and onward to Uzhhorod. On the day of the incident, however, operations at Uzhhorod Airport were suspended due to runway maintenance issues, forcing incoming flights to divert to the nearby military airfield at Mukachevo. Unfortunately, poor weather conditions had also closed Mukachevo Airfield, causing flight N-75 to be held at Ivano-Frankivsk Airport.

Once weather conditions improved, forecasts along the route indicated extensive stratocumulus cloud cover with bases between 100 and 150 meters and tops reaching up to 1,000 meters. Visibility ranged from 1,000 to 1,500 meters amid mist and cloud icing conditions. Flight N-75 departed Ivano-Frankivsk at 14:51 and attained cruising altitude by 14:57, stabilizing at approximately 3,000 meters. At 15:04, Lviv air traffic control instructed descent to an altitude of 2,400 meters due to traffic management requirements. The crew confirmed passing the Vysoke waypoint at that altitude at 15:09 before switching communication to Mukachevo airfield control while maintaining a speed near 400 km/h.

Around 15:14, approximately four minutes before reaching the Serednie waypoint, the crew initiated descent at a vertical rate of about 7.5 m/s down to an altitude of 2,100 meters and reduced speed to roughly 300 km/h. The descent continued until reaching approximately 400 meters altitude; it is believed that the landing gear was extended prematurely during this phase. The aircraft entered cloud cover during descent and emerged after six minutes. Over Mukachevo, stratocumulus clouds were present at around 120 meters with an ambient temperature near −1°C; visibility was limited to about 1,100 meters with calm wind conditions and mist.

The controller advised that landing would be conducted on a magnetic heading of 22°. Following this instruction, the crew executed a turn opposite to their previous course and began their third turn roughly eleven kilometers from the runway. While performing the fourth turn at a speed of approximately 310 km/h, flaps were extended fully for landing configuration, resulting in a speed decrease of about 45 km/h over fifty seconds. To compensate for this reduction in velocity, engine power was increased when speed dropped to around 260 km/h. Upon completing the fourth turn near 15:24 and aligning with the final approach course, engine thrust was reduced while flaps remained fully deployed. Sixteen seconds later, as speed declined to approximately 240 km/h, engine power was again increased by the pilots. The velocity fluctuated between dropping to about 220 km/h then rising back to near 230 km/h before another slight reduction in engine power.

At an altitude around two hundred meters above ground level during attempts to stabilize flight attitude, pilots initially pushed the elevator control forward causing a sharp nose-down pitch. Reacting swiftly, they pulled back on the elevator in an effort to raise the nose; however, this maneuver resulted in a left bank reaching up to thirty degrees. Despite recovery attempts by the crew, at approximately 15:25 the inverted An-24 collided with wooden pole wires located about one hundred meters beyond the outer marker beacon before crashing onto a dirt road in a field area where it was completely destroyed by impact and fire. All twenty-four occupants lost their lives.

Causes

Following a thorough review of the flight recordings and an analysis of the aircraft debris, the technical investigation team determined that the anti-icing system had not been engaged.

The accident was attributed to a loss of longitudinal control during the final approach phase, likely due to an inadequate margin of attack angles on the horizontal stabilizer when configured for landing with flaps extended to 38° amid light icing conditions.
Additional contributing elements included:

1. The absence of alerting information for the crew regarding the stabilizer approaching critical angle thresholds.
2. Failure to activate or early shutdown of the anti-icing systems for both wings and stabilizer despite light ice accumulation (2-3 mm).
3. Lack of dependable onboard indicators signaling the presence of ice formation on the aircraft.

The Ministry of Aircraft Industry's official report contained this observation:

The longitudinal stability loss (resulting in a nose-down pitch) occurred as the control column was pushed forward prior to passing the outer marker. This is explained by flow separation on the lower surface of the stabilizer caused by ice accumulation on its leading edge, combined with flaps extended to 38° and engine power increased to 50kg/cm². The icing developed because the crew did not engage the wing and tail anti-icing systems, further worsened by the absence of any advisory from air traffic control about anticipated icing conditions.

External links

• Template:ASN accident
• "Crash of an Antonov AN-24 in Mukachevo: 24 killed". B3A Aircraft Accidents Archives. Archived from the original on 2015-04-02. Retrieved 2015-03-31.