Iran Aseman Airlines Flight 6895

Investigation

The Interstate Aviation Committee (MAK) attempted to retrieve data from the flight-data and cockpit voice-recorders, which were badly damaged in the fire which destroyed most of the aircraft. While disassembling the casing, both the mechanisms of the tape recorder and the tape media in the voice recorder were found in damaged condition, but the MAK attempted to read the data from the damaged media. The 320 mm of the FDR tape was damaged by fire. This resulted in 13 seconds of missing data. The recorded audio on the CVR was of a prior flight (Flight 632). It was then determined that the CVR was not working properly on flight 6895.

The MAK has released its final report. According to the report, the forward left cabin door was not closed completely, most likely due to a jammed seal. The MAK stated that this did not contribute to the accident. It further stated that lack of pressurization did not require an urgent landing using a visual approach, and therefore pilots should have used an instrument approach.

During the visual approach, the crew realized they were too fast and too high to land, and therefore decided to make a 360 degree orbit to reduce their speed and altitude before landing. The decision to make the turn was made at 3.3 nmi away from the airport reference point.

While executing that turn, the pilot flying descended below the minimum maneuvering altitude, failed to maintain visual contact with the runway, failed to properly monitor altitude and ignored automated warnings about terrain proximity (TAWS).

The aircraft was in a 10 degree left turn, with landing gear down, flaps 15 and speed at 160 kn when it impacted ground.

Conclusions

The MAK concluded that, despite holding proper licenses, "the analysis of the crew’s actual actions during the approach, their explanations and enquiries suggests that the crew was not properly trained for visual approaches".

The MAK also concluded that the aircraft was "reacting as expected to control inputs" and "the airframe, aircraft systems and engines as well as the avionics [...] were operative until the impact, except the cabin not pressurizing and the [cockpit voice recorder]".

MAK concluded that the cause of the crash was the crew allowing the altitude reduction of the aircraft at night to a height below the minimum height during a visual approach for an emergency landing at the airport of departure due to depressurization caused by a failed left front door seal, which led to the collision of the aircraft with the ground, the destruction of the aircraft structure followed by fire and death.

According to the report, the combination of the following factors contributed to the accident:

Deviations from the Boeing 737-200 standard operating procedure and pilot flying / pilot monitoring task sharing principles;

Non-adherence to visual approach rules, as the crew did not keep visual contact with the runway and/or ground references and did not follow the prescribed procedures after they lost visual contact;

Loss of altitude control during the missed approach (which was performed because the PIC incorrectly evaluated the aircraft position in comparison with the required descent flight path when he decided to perform visual straight-in approach);

Non-adherence to the prescribed procedures after the TAWS warning was triggered.