Examining black box data of Mi-17 helicopter an intricate process involving 32 flight parameters

The helicopter’s cockpit voice recorder and flight data recorder, popularly known as 'Black Box' even though it is bright orange in colour, is recovered from the crash site on Thursday morning

Vijay Mohan

Tribune News Service

Chandigarh, December 9

Experts will be examining 32 flight parameters while investigating the crash of the Mi-15 V5 helicopter that crashed near Coonoor in Ooty on Wednesday, killing Chief of Defence Staff Bipin Rawat and 12 others.

The ill-fated helicopter’s cockpit voice recorder and flight data recorder, popularly known as 'Black Box' even though it is bright orange in colour, was recovered from the crash site on Thursday morning. Examining flight data is a tedious and intricate process that can take a long time.

“The number of flight parameters recorded in helicopters and smaller transport aircraft is lesser than that in fighter aircraft,” an IAF engineering officer said. “In the case of fighters, given the flight configurations and operational environment and weapons firing, 104 parameters need to be recorded. Larger, multi-engine aircraft can have a different number of parameters,” he added.

All IAF aircraft operating bases have facilities to download and analyse flight data as these are part of routine flying training and technical maintenance procedures. Such facilities are also available with IAF’s base repair depots as well as with Hindustan Aeronautics Limited (HAL), the public sector aircraft manufacturer.

“Given the sensitivity of this case, it remains to be seen where the contents of the flight data recorder (FDR) and cockpit voices recorder (CVR) are analysed,” a senior IAF officer said. “Several establishments, including the IAF airbase at which the helicopter was based, No 3 Base Repair Depot (BRD) at Chandigarh, where it was assembled and serviced, Inspector General (Flight Safety) at Air Headquarters and HAL, which is associated with Russian FDR technology as it also produced FDRs for MiG series aircraft, could be involved in the investigations,” he added.

FDR and CVR record the flight parameters of an aircraft such are speed, altitude, engine temperature, power output, oil pressure, hydraulics, g-forces, communication between the aircrew and radio transmission between the pilots and the ground control. It is vital for accident analysis and is also used for performance evaluation and training. It is mandatory for all military and civilian aircraft above a specified weight to be equipped with FDR and CVR. These are of various types and sizes.

IAF officers also cautioned that just recovering the FDR and CVR does not mean that the required data would be available for investigations. “Black boxes are designed to withstand tremendous heat and pressure for a limited period and are not totally immune to damage. If exposed to fire for long, where the temperature could be about 1,000 degrees high or a severe impact during a crash, it could be damaged,” he added. “In cases where there is a problem in accessing the contents, the FDR and CVR may have to be referred to the original equipment manufacturer,” he added.

The Mi17-V5 is a Russian-origin medium lift helicopter that the IAF began inducting in 2012 to replace the older Mi-8 and earlier versions of the Mi-17 to meet its requirements for tactical airlift.

According to IAF sources, the Mi-17 is equipped with the SARPP-12 FDR and the MS-61 CVR where data is recorded in wave form on a photographic film that has to be developed in a laboratory for recovering the data. The Air Force have initiated a project to replace them with indigenously developed equipment having solid state memory where data can be downloaded, processed and stored digitally in a more convenient and efficient way.

Execution of the project is being done by 3 BRD here, which is also taking up several other projects to modify and retrofit Mi-17 helicopters with indigenously developed equipment to enhance their operational capability and also to reduce dependence on foreign suppliers for aero-spares.

A modern, highly capable aircraft forming the backbone of the IAF’s vertical airlift component, the MI-17 V5 is powered by two engines and has a maximum speed of 250 km per hour and a service ceiling of 6,000 metres.