1951 Novosibirsk Il-12 crash

1951 Novosibirsk Il-12 crash

Accident
Date	17 November 1951 (1951-11-17)
Summary	Icing, stall, loss of control
Site	near Novosibirsk-Severny Airport, Novosibirsk Oblast (Russian Soviet Federative Socialist Republic, USSR)
Aircraft
Aircraft type	Ilyushin Il-12P
Operator	Aeroflot (1st Separate Aviation Group GVF)
Registration	CCCP-Л1775
Flight origin	Severny Airport, Novosibirsk
Stopover	Omsk-Centralny, Omsk
Destination	Vnukovo Airport, Moscow
Passengers	19
Crew	4
Fatalities	23
Survivors	0

The 1951 Novosibirsk Il-12 crash was an aviation disaster involving an Ilyushin Il-12P aircraft operated by Aeroflot on 17 November 1951, which resulted in the deaths of 23 people.

Aircraft

The Il-12P with tail number USSR-L1775 (manufacturer's number 93013112, serial number 31-12) was produced by MMZ "Znamya Truda" on February 21, 1949, and soon transferred to the 1st Separate Aviation Group of the Civil Air Fleet. At the time of the crash, the aircraft had logged 2007 flight hours.

Preceding circumstances

Il-12 CCCP-Л1775 arrived in Novosibirsk on flight No. 6 from Moscow. The crew consisted of the commander (PIC) Pyotr Petrovich Averin, copilot Ruben Sergeyevich Aslanyants, flight engineer Ivan Matveyevich Kurchakov, and radio operator Viktor Ivanovich Kuznetsov. At that time, numerous passengers had gathered at the Novosibirsk-Severny Airport, traveling from Yakutia to Moscow. It was decided to organize an additional non-scheduled flight using this Il-12 for them. A total of 19 passengers boarded the aircraft.

Over the past day, a complex weather situation had developed at the airport, with the AMS issuing about five forecasts. The forecast for 09:00–15:00 indicated the formation of ice, but the forecasts for 12:00–18:00 and 15:00–21:00 did not. Nonetheless, the head of AMS and a meteorologist verbally informed the Aerodrome control tower dispatcher Shipitsin and the deputy head of Novosibirsk airport for flight services Uvarov, who was the flight supervisor, that icing would still occur due to a delayed cold front. According to the meteorologist, he also informed the airport head Zagorodny, the deputy head of the West Siberian Directorate of the Civil Air Fleet (ZSU GVG) for flight services Broverman, and the head of the ZPS GVG Filanovsky. However, all three confirmed the consultation with the meteorologist but denied receiving a warning about icing.

Between 15:00 and 16:30, the sky was completely covered with stratiform and ragged-rain clouds at an altitude of 80–100 meters, heavy wet snow was falling, the wind was moderate from the south, visibility was 1000–1500 meters, and the air temperature was +0.4 °C. However, at 16:10, the wind shifted to the northwest, causing the temperature to drop to −4 °C, and dry, fluffy snow began to fall instead of wet snow. The wet snow that had accumulated began to freeze. While the aircraft were taxiing from the parking area to the apron and then to the start position, they were covered with a thick layer of snow, so before taxiing to the start, they were swept of wet snow. If before the frost, the wet snow could still be removed with a broom, the frozen snow turned into an ice crust 12–15 millimeters thick.

Crash

At 15:34, a Lisunov Li-2, CCCP-Л4398, piloted by a crew led by Commander Khristovson, was taking off from the airport. However, immediately after liftoff, a left bank occurred, so the pilot decided to abort the takeoff, reduced throttle, and shut down the engines. The aircraft rolled out beyond the concrete runway and stopped 50 meters away. Khristovson then taxied to the parking area and went to the control tower, where he reported the incident, caused by snow on the aircraft, to Shipitsin, Zagorodny, and Averin (pilot of Il-12 CCCP-Л1775). At 16:05, crew commander Khorunzhiy came to his Il-12, CCCP-Л1417, and found it covered in ice that could not be removed with a broom, so he refused to take off and demanded the aircraft be treated with hot water, reporting this to Zagorodny.

The airport management was sitting inside and did not notice the air temperature drop below zero and the rapid icing. They also ignored the alarming reports from pilots. Assuming that the Li-2's runway excursion was caused by a wind shift, Broverman decided to change the takeoff direction by 180°—from 195° to 15°.

At 16:22, Il-12 CCCP-Л1775, commanded by Averin, began takeoff. The clouds at that time were at an altitude of 85 meters, visibility was 1000 meters, dry snow was falling, and the icing process had already been completed. However, after climbing to 150 meters above aerodrome elevation (100 meters above the surrounding terrain), the airliner lost speed. The crew retracted the flaps and switched the engines from nominal to takeoff mode, when a stall occurred on the left wing, causing a rapidly increasing left bank. The aircraft quickly lost altitude and at 16:23 crashed with the left wing, then the nose, with running engines, into the ground 30 meters from the edge of the Mochishche quarry, 12 meters from a residential house, and 3100 meters from the runway end (2100 meters past the BPRM and 900 meters before the DPRM). The impact caused the Il-12 to turn left by 135°, after which the fuselage was destroyed to ¾ of its length (up to the 34th frame out of 42) and caught fire. The debris scattered over an area of 40 by 40 meters. All 23 people on board died.

Causes

The cause of the crash was quickly determined, as an inspection of the surviving stabilizers, fin, and right wing revealed that the leading edge of the stabilizer was covered with ice 15 millimeters thick along its entire length. Ice of the same thickness was found on the fin and fuselage in the stabilizer area. The wing had ice up to 8–10 millimeters thick.

The causes of the disaster are:

1. The aircraft was allowed to fly with a significant amount of ice on the tail section and the wings.
2. Negligent, bordering on criminal, behavior of the responsible personnel of Severny Airport, who did not stop aircraft departures after alarming signals from the crews of captains Khristovson and Khorunzhiy.
3. Criminally negligent attitude of the Il-12 crew, who allowed the takeoff with ice on the aircraft surface.
4. Lapses by AMS Novosibirsk in weather forecasting after 12:00, which did not predict ice.

Responsible parties:

1. Flight Supervisor Uvarov—left the control start station without authorization; aware of the approaching cold front, he took no measures to ensure flight safety.
2. Airport Head Zagorodny—failed to organize the work of personnel and supervise the preparation of material assets and aircraft departures.
3. Head of Line Maintenance and Repair Shops Malinovsky—failed to take measures to prepare material assets and mobilize personnel in worsening weather conditions.
4. Shift Engineer Gringaus and Control Master Pozdnyakov—did not check the condition of the aircraft before taxiing to the start.
5. Deputy Head of West Siberian Directorate of the Civil Air Fleet Broverman—did not understand the worsening weather situation and did not decide to stop flights.
6. The crew of the Il-12 L-1775.

References

3. Notable victims of the tragedy (passengers): Sheenson M.S., Borisov V. (patronymic not established), Gulyaeva (name and patronymic not established). The remains of all three were buried in a common grave at the Danilovsky Cemetery in Moscow.