Narrative:
A National Aeronautical Laboratories Saras prototype, an Indian designed light civilian transport aircraft, registered VT-XRM, was destroyed in a accident during a test flight. All three crew members were killed.
The Saras airplane was scheduled for carrying out test flight no 49, which would include inflight engine shut down and relight procedure at 10000 feet AMSL.
The aircraft took-off from Bangalore-Hindustan Airport (BLR) at 14:55. The flight was cleared to flight level 100. After completing general handling checks at 9000AMSL without any events, a single engine simulated approach was carried out on runway 09. At about 15:11 the crew were cleared to perform an overshoot.
The crew contacted the Bangalore Radar controller, who cleared them back to FL100 and proceed to sector Southwest 2 for carrying out the engine relight test procedure. The crew reported reaching 9000AMSL in sector Southwest at about 15:18.
The no. 1 engine was then shut down and secured following the test procedure at about 15:31. After about 47 seconds, the no. 1 engine relight procedure was initiated at around 9200AMSL.
After a successful left engine shut down and its securing procedure, at about 15:31 left engine relight procedure was initiated at about 9200AMSL. The propeller blade pitch was selected from feathered to fine. This led to an increased in propeller rpm from 5 to 55%. Side slip increased up to 28 degrees and bank angle changed from 8 deg right to 70 degrees left. The pitch attitude was seen reaching -42 degrees. Propeller rpm continued to increase to 91%. Then the aircraft went into a sudden dive from 9200 to 7300 for about 13 secs. The aircraft was brought under control at this altitude. The crew continued their attempt to relight the engine but this was not successful. Meanwhile the side slip remained at 22 degrees with a pitch attitude of about -15 deg. The speed remained at 130 kt and altitude reduced from 7000 feet to 5200 feet.
A second relight attempt was successful but the airplane was still in a rapid descent passing 4800 feet. Rudder pedal forces
increased to as high as 90 kg with aileron forces raising to 40 kg. The crew were not able to fully control the airplane and arrest the descent. It impacted the ground. The aircraft was completely destroyed due impact and fire.
PROBABLE CAUSE(S):
Incorrect relight procedure devised by the designer and adopted by the crew at insufficient height leading to rapid loss of altitude and abnormal behavior of aircraft resulted into accident.
Contributory factors:
a) Lack of crew coordination and cockpit procedures
b) Handling of the controls
c) Non-aborting of flight by the crew in coordination with the flight test Director after failure of first relight attempt.
d) Devising engine relight procedures by NAL without consulting the propeller manufacturer.
| Status: | Accident investigation report completed and information captured |
| Date: | Friday 6 March 2009 |
| Time: | 15:34 |
| Type: |  National Aerospace Laboratories (NAL) Saras |
| Operator: | National Aerospace Laboratories - NAL |
| Registration: | VT-XRM |
| MSN: | SP002 |
| First flight: | 2007-04-20 (1 year 11 months) |
| Total airframe hrs: | 50 |
| Cycles: | 49 |
| Engines: | 2 Pratt & Whitney Canada PT6A-67A |
| Crew: | Fatalities: 3 / Occupants: 3 |
| Passengers: | Fatalities: 0 / Occupants: 0 |
| Total: | Fatalities: 3 / Occupants: 3 |
| Aircraft damage: | Destroyed |
| Aircraft fate: | Written off (damaged beyond repair) |
| Location: | near Bidadi ( India)
|
| Phase: | En route (ENR) |
| Nature: | Test |
| Departure airport: | Bangalore-Hindustan Airport (BLR/VOBG), India |
| Bangalore-Hindustan Airport (BLR/VOBG), India |
A National Aeronautical Laboratories Saras prototype, an Indian designed light civilian transport aircraft, registered VT-XRM, was destroyed in a accident during a test flight. All three crew members were killed.
The Saras airplane was scheduled for carrying out test flight no 49, which would include inflight engine shut down and relight procedure at 10000 feet AMSL.
The aircraft took-off from Bangalore-Hindustan Airport (BLR) at 14:55. The flight was cleared to flight level 100. After completing general handling checks at 9000AMSL without any events, a single engine simulated approach was carried out on runway 09. At about 15:11 the crew were cleared to perform an overshoot.
The crew contacted the Bangalore Radar controller, who cleared them back to FL100 and proceed to sector Southwest 2 for carrying out the engine relight test procedure. The crew reported reaching 9000AMSL in sector Southwest at about 15:18.
The no. 1 engine was then shut down and secured following the test procedure at about 15:31. After about 47 seconds, the no. 1 engine relight procedure was initiated at around 9200AMSL.
After a successful left engine shut down and its securing procedure, at about 15:31 left engine relight procedure was initiated at about 9200AMSL. The propeller blade pitch was selected from feathered to fine. This led to an increased in propeller rpm from 5 to 55%. Side slip increased up to 28 degrees and bank angle changed from 8 deg right to 70 degrees left. The pitch attitude was seen reaching -42 degrees. Propeller rpm continued to increase to 91%. Then the aircraft went into a sudden dive from 9200 to 7300 for about 13 secs. The aircraft was brought under control at this altitude. The crew continued their attempt to relight the engine but this was not successful. Meanwhile the side slip remained at 22 degrees with a pitch attitude of about -15 deg. The speed remained at 130 kt and altitude reduced from 7000 feet to 5200 feet.
A second relight attempt was successful but the airplane was still in a rapid descent passing 4800 feet. Rudder pedal forces
increased to as high as 90 kg with aileron forces raising to 40 kg. The crew were not able to fully control the airplane and arrest the descent. It impacted the ground. The aircraft was completely destroyed due impact and fire.
Probable Cause:
PROBABLE CAUSE(S):
Incorrect relight procedure devised by the designer and adopted by the crew at insufficient height leading to rapid loss of altitude and abnormal behavior of aircraft resulted into accident.
Contributory factors:
a) Lack of crew coordination and cockpit procedures
b) Handling of the controls
c) Non-aborting of flight by the crew in coordination with the flight test Director after failure of first relight attempt.
d) Devising engine relight procedures by NAL without consulting the propeller manufacturer.
Accident investigation:
 |
|
Classification:
Loss of control
Sources:
» NAL Saras crashes at Bangalore - crew dead (Bangalore Aviation 6-3-2009)Follow-up / safety actions
DGCA India issued 11 Safety Recommendations
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This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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