Aeroflot Flight 17. Aeroflot Flight 17 was an aviation accident involving an Ilyushin Il-12 aircraft operated by Aeroflot on May 13, 1949 near Novosibirsk. The crash resulted in the deaths of all 25 people on board.

Aircraft 

The Il-12 (also known as the Il-12P) with serial number 93013208 and production number 32-08 was manufactured by the "Banner of Labor" plant (Moscow) on March 14 1949. The aircraft was registered with the tail number CCCP-Л1791 and was delivered to the Main Directorate of Civil Air Fleet under the USSR Council of Ministers, which assigned it to the 1st separate aviation group of the Civil Air Fleet based at Vnukovo. At the time of the accident, the aircraft was only two months old and had logged just 51 flight hours.

Accident 

The crew was performing flight 17 from Moscow to Krasnoyarsk. At 12:13, the aircraft departed from Omsk, where it had made an intermediate stop, and headed towards the next stop in Novosibirsk. According to the forecast, clouds at 1,000–1,500 meters and occasional rain were expected along the route, with possible thunderstorms later in the journey. The Omsk dispatcher received several warnings that thunderstorms were declared over Novosibirsk, but did not pass this information to the flight 17 crew and did not prohibit the flight.

At 13:28, the crew received permission to enter the Novosibirsk regional control center zone. Additionally, since 13:00, the aircraft had repeatedly requested entry into the Novosibirsk airport zone, but thunderstorm activity over Novosibirsk caused strong interference. While awaiting clearance, the aircraft began a holding pattern over Novosibirsk. Only at 14:00 did the crew manage to establish contact with the airport. Then, at 14:05, the Novosibirsk airport dispatcher gave flight 17 permission to approach and descend to 700 meters, even though the aircraft was already in the airport zone. At 14:07, the crew reported, "Entered a cloud, sometimes seeing the ground." This was the last radio transmission from the aircraft.

Over Novosibirsk, the sky was completely covered with clouds, there was heavy rain with hail, strong gusty winds, and visibility dropped to 100–200 meters. Around 14:07, 6–8 kilometers northeast of the airport, the Il-12 entered a cloud, and witnesses observed it in the clouds until 14:10. After this, the captain likely attempted to exit the cloud, making a sharp right turn with a descent. At an altitude of 70–100 meters, the aircraft exited the cloud but was in a steep bank. Continuing to lose altitude, the aircraft crashed with a 65° right bank into a four-meter-high embankment of a quarry, breaking apart, with some debris flying over the embankment and catching fire. All 25 people on board perished.

Investigation 

The "cloud" that the crew reported entering was actually the rear part of a powerful thunderstorm cloud. Upon entering it, the Il-12 unexpectedly experienced severe turbulence. Forensic examination results showed that the first officer and the radio operator were unconscious at the time of the crash, with the first officer also clutching the control yoke. It is likely that lightning struck the aircraft, incapacitating some of the crew members, causing the first officer and radio operator to lose consciousness, while the captain and flight engineer panicked, poorly monitoring the instruments. Panicking, the captain attempted to quickly exit the cloud, making a sharp descending turn, but upon exiting, encountered heavy rain with large hail and gusty winds. Additionally, the second officer's gripping of the yoke significantly complicated control. Disoriented during flight through the rain and not monitoring the instruments, the captain began to descend south and then southeast until the aircraft crashed into the ground.

The commission concluded that the immediate cause was the entry into a thunderstorm cloud and the incapacitation of two crew members due to lightning. In the conditions of rain and hail, the remaining two crew members were disoriented, and likely due to panic, did not monitor the instruments or maintain a safe altitude. Several factors significantly contributed to the crash:
 A thunderstorm not forecasted in the weather forecast.
 Entry into the cloud occurred from the rear, where it appeared less dangerous.
 Mismanagement and control issues during the flight, including incorrect weather forecasting, unstable radio communication, failure to inform the crew about the thunderstorm warning, and poor communication between airport weather services along the route.

References

Notes 

May 1949
17
Accidents and incidents involving the Ilyushin Il-12
Aviation accidents and incidents caused by weather
Aviation accidents and incidents involving controlled flight into terrain
Aviation accidents and incidents caused by air traffic controller error