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How plane crash probes are conducted

Updated December 09, 2016

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A Rescue crew member holds the black box at the remote crash site on Wednesday in this still frame taken from video.—Reuters
A Rescue crew member holds the black box at the remote crash site on Wednesday in this still frame taken from video.—Reuters

KARACHI: The primary cause of the Pakistan International Airlines ATR-42 plane crash near Havelian on Wednesday evening would be ascertained in a few weeks, but a comprehensive investigation report might take between six months and a year to finalise, former Safety Investigation Board chief Khwaja Abdul Majeed told Dawn on Thursday.

The former SIB chief said that in such cases, the aircraft debris was handed over to the SIB to conduct investigations. Two pieces of equipment are crucial in conducting such investigations: the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR). They are commonly known as black boxes and are placed securely in the tail of the aircraft.

While the CVR records the conversation in the cockpit, the FDR records in detail a report of how the aircraft’s vital parts and equipment are functioning. He said that under normal circumstances, airlines had the facility of decoding and reading the CVR and the FDR; however, in the case of a plane crash, there is a possibility of black boxes getting damaged. Hence, the airline avoids damaging the data and equipment readings and does not decode it.

Instead, the black boxes are sent to the manufacturer of the crashed aircraft — in this case, to ATR France. The black boxes will be decoded at the ATR labs.

Representatives of the SIB and the country the aircraft belonged to (in this case, Pakistan) are present when the boxes are decoded as a precaution in case the manufacturer manipulates the findings.

Soon after the plane crash on Wednesday, ATR, the plane manufacturer based in Toulouse, France, posted a press statement at its website saying: “ATR regrets to acknowledge the loss of an ATR 42-500 operated by Pakistan International Airlines (PIA) in an accident at around 4.30pm (local time). The aircraft, registered under AP-BHO, was Serial Number 663. At this time, the circumstances of the accident are unknown.”

The investigation usually takes up to one week after which the main cause of a plane crash becomes clear. The report prepares details whether a crash has occurred due to human error, equipment malfunction, weather, or any other reason.

The SIB usually declares this initial report within a month, at the most. This is followed by a comprehensive investigation report initiated by the SIB. Representatives of the airline involved (PIA), the regulator (Civic Aviation Authority), the countries whose citizens died in the crash, the aircraft manufacturer and manufacturers of equipment used in the aircraft provide assistance and input in the report.

Mr Majeed said the Civil Aviation Rules and the International Civil Aviation Organisation (ICAO) suggest that the comprehensive report on a crash be completed within six months or at most a year. He said that since the SIB was not involved in a major probe at present, the investigation into the PK-661 plane crash should not take more than the prescribed time.

The comprehensive report is widely circulated, especially among aviation-related stakeholders, to enable them to know the cause of the accident and take precaution so that a similar tragedy can be avoided in future.

Published in Dawn, December 9th, 2016