From Groupie Kapil’s Pen

Group Capt Kapil Bhargava, with his razor sharp memory and an eye for detail has sent a comprehensive write up on the Test Pilots lost on the HF – 24. He mentions that of the total 24 test pilots lost so far, the Marut and the Gnat both claimed 4 each. All four Marut accidents occurred in two years between 1970 and 1971

“1.    Groupie Suranjan Das’ crash (1970) was perhaps partially pilot error. He was the greatest supporter of the HF-24 Mk IR with reheated Orpheus engines. It had the prospect of being earlier and better than the Jaguar. Its performance was less than it would have been if the rear fuselage had not simply been enlarged by HAL to house the larger engines and their nozzles.  The nice area rule of the original design had been vitiated badly. All the same, the performance of the aircraft was impressive. All it needed was to get the right avionics. According to me, the other design work should have been for the addition of a second hydraulic system, and of course streamlining the fuselage a lot better than the fat end.

While taxiing out to the take-off, Groupie Das used to keep the clam shell canopy unlocked and hold it up slightly to get some fresh air. There was no retaining lever. It seems that on the fateful day, he forgot to lock it prior to beginning the take-off run. The canopy opened during the ground roll. The hinges were too strong for it to fly off. Ejection through the canopy, as in all Maruts, would almost certainly have led to killing the pilot. Hence, the canopy had to be jettisoned.  Ejection, till the canopy was not in the way, was prevented by a locking pin. This pin was pulled out by a lanyard which would be extracted during jettisoning of the canopy.

For Groupie Das, with the canopy already open, its jettisoning was no longer possible. Ejection was also impossible as the seat was not armed till the pin was pulled out. The drag from the canopy was large and the aircraft did not get airborne. There was a debatable possible failure of the reheat of one engine. In short Groupie Das had no options left and died in the crash.

2.   The crash of S/L (Kiddo) Narayanan (1970) was somewhat mysterious. During the monsoon. he ferried the very first HF-24 prototype to Goa and flew over Dabolim airfield. A request to make another run to show off the aircraft was passed to him on the R/T. He came round heading west again but was seen to be well to the left of the runway. From about 1000 feet or so his aircraft suddenly dived into the Goa Bay. The drizzle and low clouds present at the time may have caused disorientation, or the tail trim had run away. But no cause was determined, since the aircraft was never recovered from the sea.

3.   Winco Jagat Kishore Mohlah (1971) was flying the aircraft at 10,000 feet heading west in the area north of Bangalore airfield. Suddenly his aircraft dived into the ground. It hit granite rocks where the engines embedded deep into them. There was almost nothing left of his body. A trim runaway was suspected but never proved. (His son Gp Capt Sridhar Kishore Mohlah is also a test pilot and is currently commanding the Air Force Test Pilots School).

4.    In the last HF-24 crash involving a test pilot, S/L Sapre (1971) was patently lost for no fault of his. With the Bangladesh War looming on the distant horizon, HAL had tried to clear the aircraft for four-gun firing. The vibration level in the aircraft when firing four guns was frighteningly high, almost violent, during butt tests. The traces of flight test records showed very high amplitudes. Yet HAL had cleared it.”

Further details about the aftermath of  Sqn Ldr Sapre’s accident have already  been put up in the post on “Meena Sapre’s Gesture to the Marut”.

For those interested further in knowing more about Gp Capt Suranjan Das, Groupie Kapil has written a very enlightening article on him
Suranjan Das – the man and the professional”

4 Responses to From Groupie Kapil’s Pen

  1. Dara says:

    Groupie Chakko adds:
    “Of course I am amzed at Groupie Bhargava’s recall of the events of those days. Bless him.
    I was the Senior Tech Officer in the HF24 Project Team, around that time till 1967, stationed at the HAL. This unit was commanded by the late AM Zoot Zaheer.
    I am familiar with most of the design concepts of the basic HF24. I was present at some of those HAL butt tests firing guns. I do remember that there was a problem with the gun mounts during firing the guns in bursts.”

  2. kp sreekant says:

    Twice during the 71war I had mix-ups with sabres
    both 2a/c formations that we flew for OAS missions
    at that time. In both missions the first one led
    by our flt.cdr at that time joe Bakshi and the second
    one led by Brian deMagry I had manoeuvred behind the
    the sabres and had opened fire. Just before the war
    we had heard about late Sqn ldr Sapre’s fatality during
    a 4gun firing sortie where if I remember correctly
    one of the power control pawls had reverted to manual.
    This accident prevented me from selecting 4 guns in
    both scuffles.
    Warm regards
    KP Sreekant

  3. su says:

    so what was the real modification that resolved the problem?.
    i salute the test pilots/engineers who gave us a safe platform many years later

  4. Dara says:

    Subsequent to this, AM Brijesh Jayal, sent some more information regarding the Marut and four gun firing experience.

    “On Saper’s unfortunate accident, I can perhaps add a personal experience.
    We in A&ATU carried out service acceptance trials on the HF 24 during 1966-67 and later converted No 10 to Maruts in Jamnagar.It was possibly in 1966 that I was carrying out some armament trials in Jamnagar towards this service acceptance. The first attempt at four gun firing on a Marut by A&ATU is still fresh in my mind. As I pressed the trigger, it appeared that all hell had broken loose in the cockpit. All I noticed at the time was a thud on my bone dome and bits and pieces flying around the cockpit. Mercifully, the experience was disconcerting enough for me to let go the trigger and take stock-so the four cannon burst was very short.On landing we realised that the Gun recorder camera had broken off the mounting and hit my bone dome, some other knobs and switches in the cockpit had broken and had to be retrieved.Subsequent analysis confirmed the unacceptable vibration levels.If I’m not mistaken this must have been the last time that the AF fired four cannons on the Marut, until Saper’s flight.

    Best wishes

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