Translated material
Gray feathers of death
According to the main version, the An-12 that crashed in the Moscow region was “shot down” by two birds at once
Members of the state commission to investigate the crash of the An-12 cargo plane , which crashed on August 1 in the Moscow region in the vicinity of Domodedovo airport, as Vremya Novostei learned, have decided on the main version of the tragedy. An examination of the engines of the deceased airliner, which was carried out by representatives of their manufacturer - the Zaporozhye Engine Plant, showed that the cause of the accident, most likely, was a fatal and almost incredible coincidence of circumstances - two birds getting into the power units of the An-12 at once . The location of the engines and difficult flight conditions in such a situation, according to experts, left the crew no chance of salvation.An An-12 cargo plane, owned by Atran Airlines, took off on the night of August 1 with a cargo of aircraft parts from Domodedovo to Komsomolsk-on-Amur with intermediate stops in Bratsk and Omsk. Four minutes after takeoff, the plane disappeared from radar screens. A few minutes later, the crew commanders of several airliners coming in to land reported to the flight director about an explosion near the airport. The burning wreckage of the An-12 was discovered 4 kilometers from the runway, in a forest adjacent to the Domodedovo cemetery, near the village of Semivragi. All seven members of the plane's crew were killed.
The version that birds got into the plane's engines was considered, among others, by investigators almost immediately. Based on the data from the “black boxes,” experts quickly found out that two of the An-12’s four engines failed a minute before the crash. However, experts did not have exact data on why this could have happened - one of the flight recorders, which recorded the operation of all the components of the liner, was completely destroyed after a strong fire that started during the fall. Accordingly, the only hope in finding out the causes of the tragedy was an examination of the aircraft wreckage.
Having dismantled the power plants, the engineers, according to our information, stated that the reason for the shutdown of two An-12 engines was “the ingress of an organic object.” Experts did not find any other reasons for equipment failures.
Now the picture of what happened, from the point of view of technicians, has been restored almost completely. At an altitude of about 100 meters, birds first hit the gas track of the 4th and then the 3rd power plant (both located on the right wing of the aircraft in the direction of travel). In both cases, surging occurred - a malfunction when the engine begins to “choke” on fuel - and, as a result, automatic feathering of the propellers (the blades of the stopped propellers turned edge-on towards the oncoming flow). This situation for the four-engine An-12, whose propellers rotate in one direction, is, according to experts, simply catastrophic. Due to the unidirectional rotation of the propellers on this machine, a torque arises that seems to tip the plane onto the right wing. Compensation for this force is carried out precisely due to the operation of the fourth (far right) engine. Although its failure is considered critical, it is still possible to save the car in this case. The failure of two engines on the right side at once for the An-12, experts believe, is an almost unrealistic situation. In this regard, the aircraft is built so reliably that this situation is not even considered in the flight documentation.
Theoretically, as experts believe, in such a situation the crew could try to save the plane in only one way - turn the wheel to the left as far as possible, compensating for the torque by the operation of the ailerons and flaps, and try to land on the course of travel. In this case, the car can only move with a decrease until the speed drops below the “effective action of the rudders” mark. True, only testers and theory talk about this. What could be done in this particular situation - on takeoff, in the night sky and above the forest, one can only guess.
Nevertheless, the crew, according to experts, did everything possible to save the liner. One of the engineers who studied the engines said with undisguised respect that “the crew worked surprisingly well, following all the rules.” The tragedy itself, in their opinion, became possible due to a rare combination of factors. Firstly, before the An-12 in this direction from the airport there were no takeoffs for about 1.5 hours, and accordingly other planes did not frighten the birds. Secondly, cases of birds getting into the engine at night are extremely rare - usually at this time most of them are simply sleeping. Thirdly, the almost simultaneous impact of birds on two engines at once, located on the same wing, is also an almost incredible fact. It would hardly have occurred to anyone that this was possible, but nevertheless, according to the main version of the investigation, it happened.
The Interstate Aviation Committee (IAC), which is leading the investigation into the plane crash, does not officially comment on the progress of the investigation. But in a private conversation, experts admitted that the main work to establish the causes of the tragedy was almost completed - only minor clarifications and “paperwork” remained.
The prosecutor's office and ornithologists will most likely determine the culprit of the tragedy. It is the latter who will have to determine, from the remains of gray feathers, which of the birds did not sleep that night and which fell into the air intake of the engines of the crashed "Ana". As experts admit, there is little data - the approximate size of the bird and a few gray feathers. The rest of the turbine simply burned and was thrown away. As for the prosecutor's office, the task here is not easy. Domodedovo Airport has its own ornithological service, created specifically to ensure flight safety. The airliner, as already mentioned, fell 4 kilometers from the runway, behind the airport fence, but whether the collision took place in the service’s area of responsibility is still unclear.