Flying the Bofors into Thoise
- Category: The Siachen Glacier
- Last Updated: Monday, 12 June 2017 22:03
- Written by Gp Capt Anant Bewoor VM (Retd)
- Hits: 21746
The Decision About Bofors.
The Siachen battles started, as we all know, in June 1984. In about Mar / Apr 88, four years after it all began, a decision was taken to induct a Battery of Bofors 155 mm guns into the battle zone. Notwithstanding the scam attached to the gun, it is a wonderful piece of artillery for more than one reason. The battles of the Kargil salient in 1999 abundantly established beyond doubt that the Bofors field guns were worth their scam. The Bofors comes with its own Scania truck and other associated equipment like the automatic loader, and a Prime mover for the gun. No wonder it was called the Shoot & Scoot Gun.
In early May 1988, Wg Cdr 'Pishton' Jadhav, Flt Cdr 44 Squadron got orders to position two aircraft at Tezpur and transport a Battery of Bofors to Chandigarh for further induction into Thoise. For those who do not know, Thoise is in the Shyok valley North of Leh at an altitude of 10059 ft or 3067 metres. The RW length in 1988 was only 6050 ft or 1845m. The Antonov-12 had never landed at Thoise, the RW being too short for that aircraft. Therefore, Thoise does not appear in the history books of 44 Squadron. That was changed by the IL-76 when Gp Capt Ashok Goel then Commanding Officer of 44 Squadron, did the trial landing at Thoise in 1986. He followed exactly the same procedure as laid down by the Packets of 12 Squadron, 19 Squadron, 48 Squadron and Paratrooper Training School (PTS) involving 2-3 sharp 90 deg turns before finally aligning with RW 29, river Shyok flowing Westwards, just North and to the right side of the approach path. The mountains on either side are overwhelming and rise ever so sharply from the riverbed. The IL-76, at the time of writing, the largest aircraft to ever land at Thoise, is totally dwarfed and rendered insignificant against the sheer majesty of the Himalayas.
|IAF Transports at Thoise airfield. An An-32 in the foreground shares the tarmac with an IL-76 in the rear.|
Under command of Raja Goel, 44 Squadron had made successful flights into Thoise with 9 KL fuel bowsers, BRDM Armoured Personal Carrier's and BMP Infantry Combat Vehicles. Now it was the turn of the Bofors to move in. On 08 May 88, exactly 43 years to the date after Hitler's Germany surrendered, two IL-76s airlifted the guns, vehicles and ancillary equipment from Tezpur to Chandigarh in one day. Loading the Bofors for the flight into Thoise was quite different than bringing them from Tezpur ro Chandigarh. Only the correct quantity of guns and equipment was loaded to remain within the max landing AUW limitations at Thoise. We wanted to have enough fuel to get back to Chandigarh without asking for priority landings and worrying about having at least 5 tons of fuel in the aircraft. An IL-76 is prohibited to be airborne with less than five tons of fuel in the tanks. It takes about 45 min to fly into Thoise from Chandigarh and keeping safety margins, we refuelled 24 tons, and loaded 34 tons of cargo. For some strange reason the 34 tons limit fitted the loading plan of the Bofors battery beautifully. Normally, what the Army wants to put inside an IL-76, is far in excess of what can actually be accommodated.
Major (now Brig) Buttar was the Battery Cdr. He would 'drive' the gun up the ramp and into the waiting cavernous belly of the IL-76. He would later 'drive' the gun out of the aircraft at Thoise. He did this many times at Chandigarh to train himself and also train other Gunners on this rather delicate operation. The gun could be loaded barrel facing forward or rearward. Very deftly, Buttar would lower the barrel in stages to keep the tip well below the ceiling of the ac. As was the case with the T-72 tank, the Bofors too had its own peculiar problems negotiating the loading sill of the IL-76. Eventually, the gun was parked with its long barrel way up at about 70 degrees into the sky, making space for other equipment to be kept under the barrel. Ideally, the barrel should not be pointing towards the sky, but if the barrel were kept level, as it should be, very little else would have fitted in the aircraft.
During loading, the tarmac at Chandigarh would be a mass of curious Army and Air force personnel, to witness a piece of field artillery, actually "driving into an IL-76'. One gun was loaded with its barrel pointing forward, the other pointing backward. It took four sorties to move the Battery from Tezpur to Chandigarh. It would take eight sorties to fly it into Thoise.
The honour to induct Bofors into Thoise was given to 285 Medium Regiment and 'Papa' Battery under command of Maj Buttar was selected for the induction.
Preparing For Thoise.
Before we go into the details of flights into Thoise, it is relevant to understand how the max AUW for a landing at Thoise was determined. The Shyok valley at Thoise is very much narrower than the Indus valley at Leh. The lateral distance, North-South, between the peaks is not more than about 2 kms. The valley becomes even narrower as the Shyok river flows onto Chalunka region of Partapur sector. Khardung La, the link between Leh and Thoise, is way to the East near Tri-Junction and to get to it after an overshoot on RW 29 at Thoise, means turning around through 180 degrees in the Shyok valley. Those of us who know Thoise, will shudder at this prospect. The reader may well ask what has Khardung La, a road pass, got to do with the IL-76? Just as it is for vehicles, so is it for aircraft, Khardung La is the lowest point on the mountain range that separates the Indus from Shyok. Readers who may have never gone to Thoise, and even for those who have, need to be mentally with the pilots and navigators as they are deliberating and deciding what should be the max AUW for a landing at Thoise.
The overriding factor in this decision is, when should the IL-76 commence an overshoot on the approach for RW 29, so that it can climb to the desired height, and safely turn around within the Shyok valley, to either make another approach, or escape to Leh across Khardung La at a height of 5. 6 kms. It is a breath taking exercise. To decide on the max AUW for landing at Thoise, we decided to conduct trials at Agra and simulate conditions as prevalent at Thoise. The Doppler in the IL-76 allows the navigator to read off the drift from a predetermined path. Till now we were landing in Thoise at an AUW in excess of 140 tons. While that by itself may be acceptable if recorded in the aircraft Log Book Form 700, the factor of overshoot and turn-around had to be reconsidered. There was a major lacuna in the SOP with safety implications. It needed rectification to ensure that an overshoot can be safely executed at Thoise. So what we did was to make an approach at Agra at a height of 3370 metres. Why 3370 metres? Thoise is at an elevation of 3070 metres, and at a distance of 6 kms from touchdown the aircraft would be at 3370 metres. Why 6 km? If the IL-76 is to overshoot, thereafter lose one engine and yet be able to climb to the desired height, which we will come to later, and do a 180 degree turn to come back over Thoise, fly Eastwards and cross Khardung La at the prescribed height of 5.6 km, then that overshoot must be initiated at a distance of at least 6 kms East from the beginning of Thoise runway. If the aircraft comes any closer, it may not be able to clear the ridges West of Thoise, and execute a safe turn around, it would probably crash into the mountains and become a statistic.
To simulate this procedure at Agra we would make an approach at an altitude of 3370 m and at a distance of 6 kms from the RW, we would initiate an overshoot, retract under carriage, lift the slats / flaps to 14/30 and then bring No. 4 engine to IDLE. In this configuration we would intentionally drift to the right by a km or so and continue climbing to 4500 m and calculate the forward distance we had covered from the start of the overshoot. This distance we would superimpose on the map of Shyok valley to see whether we would be 'able to make it or not.' The IL-76 had landed at Thoise many times. Never had an overshoot been attempted. A trial had to be done to establish how the overshoot is to be executed. No one knew whether it was possible. Pilots, and indeed the crew, had to be confident of "going round" at Thoise. The procedure we wanted to put in place was that, if you are closer than 6 kms to 29 dumbell at Thoise, then you have to land. The approach to Thoise is not easy. The ground falls away as one gets closer to touch down, very much like at Leh, and the height above ground is maintained using the radar altimeter. There are predetermined landmarks on the approach to cross check distance to touch down, versus height above ground and readings of the pressure altimeter The last check is abeam a Pimple on the left. Today, in 2006, Thoise RW is about 9,000 ft in length, in 1988 it was less than 7000 ft. Our trials at Agra indicated that with 140 tons AUW, and an ambient temperature of +15 deg C or less, it was possible to overshoot from 6 kms East of the RW, climb to 4500 m, and turn through 180 degrees for Khardung La This conclusion at Agra was not good enough, on site trials had to be done for validation. We put the proposal to HQ CAC where the Air II was Air Mshl 'Ken' Nair (now Retd). We discussed it with the Director T & M, VG Kumar (now Air Mshl Retd). Permission was given and we planned a flight from Agra to Thoise ending with a landing at Delhi. We were to give an immediate debrief to Director T&M. I knew the Director well and he said, "Anant, be very careful, do it well, and don't be predisposed". What VG was telling me was not to be foolhardy nor do the trial with a predetermined result. Do not 'situate' the 'appreciation' was VG's advice.
|The view from NNW looking down on the Thoise Runway at 10059' AGL. Thanks to Google Earth, the general public can get a view of most of the major airfields in the sub-continent. (Pic Courtesy : Google Earth)|
Overshoot Parameters Defined.
Well, off we went on a bright April morning. Wg Cdr RV Kumar (Now Air Cmde retd) was with me in the right hand seat. A good friend, a competent pilot, fellow instructor in Bidar, and had trained with us in USSR. I could not have chosen a better person for this trial. The navigator was Wg Cdr MK Singh, who would guide us to Maldives seven months later. We had planned the sortie with an empty aircraft, refuelled so that over Thoise, we would have an AUW of 140 tons. The whole exercise was being done to decide whether the max landing weight for Thoise be fixed at 140 tons or less with the overshoot parameters being the overriding factor. We arrived at Tri- Junction by 0715 hrs to be within the temperature limit of +15 degrees, and settled on the final approach for Thoise RW 29.
As the navigator called out "7 kms to touch down", we prepared for the overshoot and opened all four engines to take off power. The aircraft surged forward.
"Under carriage up"" I commanded, the wheels started retracting.
10 seconds later I ordered "Slats to 14, Flaps to 30".
The engineer duly retracted them and confirmed their new position. At about 3500 metres I brought No. 4 engine to IDLE and started the drift to the Northern edge of the valley. Power was reduced to climb rating on the 3 live engines. We got a Rate of Climb (ROC) of 3m/secs or 600 ft/min. Not bad, but would have loved to get 4m/sec. Soon we would reach 4 kms above sea level and now the engine thrust would keep falling with height.
"Starboard clear, well away from the mountain" came RV's voice.
We kept climbing and kept inching to the right hand side, till the navigator warned us on intercom,
"Drift is 1.2 km starboard. Commence straight climb out".
We trimmed the aircraft and were now flying parallel to the mountain. All eyes were looking out and trying to judge when we would have to open No. 4 and climb away because we were not going to clear the ridge in front. But we were climbing well, and as is the rule for flying in the mountains, we kept seeing more and more of the ridge in front of us indicating that at this rate of climb we were going to clear it. That particular ridge was at a height of 4200 metres, but beyond it were peaks at 6.5 km and higher.
Soon we would have to turn through 180 degrees executing a left hand turn. In all our trials we had always drifted to the right with the intention of doing the 180 degree turn to the left, because the captain of the IL-76 sits in the left seat. He must be able to see where he is taking his aircraft. We were now approaching that well known landmark with which all Dakota, Packet and AN-12 aircrew are familiar, Birla Mandir. A lone grandiloquent rock structure rising from the valley floor at about three km all the way up to 4 km plus. A check point for all aircraft flying into Thoise and beyond while coming in from Srinagar or Pathankot via Dras and Kargil, Birla Mandir was abeam me now, and we were at 4300 m, higher than a flat ridge where the R. Shyok enters the Chalunka valley to finally flow into Pakistan Occupied Kashmir. It was time to turn as well as level out. MK, RV and the Flt Engineer had made notes on all parameters of distances, drift, ROC, power, fuel flow, temperatures etc. The Tail Gunner kept calling out how far the wing tip looked from the mountain. No problem there "All clear" he had said over and over again. In the IL-76, the pilots cannot see the wing tips. During taxying it is the Tail Gunner who advises on clearances from ground obstructions.
The atmosphere on the flight deck was tense, we were well below the high peaks and we could not go any further West. I put in a turn of 20 degrees. "Check the bank RV" I told my co-pilot. We could have gone up to 30 degrees but first I wanted to check whether 20 degrees is enough. We had levelled out at 4.3 km, and had gained a height of 930 metres from start of the Overshoot. The 20 degree bank was enough. Speed was increased to just above climbing speed. The silence on the intercom was deafening. This was the first time I was doing this kind of flying, proving the limitations of an aircraft to operate in the valleys of the upper Himalayas
Later I wondered if it should not have been done by ASTE along with Soviet pilots. Since 44 Squadron was flying into Thoise and it was more than 3 years since the aircraft had been in India, it was incumbent on us to satisfy ourselves that regular operations into Thoise had adequate safety margins. Which is why I was turning K-2878 around Birla Mandir at an altitude of 4.3 km in the Shyok valley of Ladakh. How was I to know that I would fly this very aircraft to Hulule airport in Nov 1988?
By now we had turned through 90 degrees, and the 20 degrees of bank seemed good enough. "Lets increase bank to 30 degrees and see how she handles, and then we will have something more worthwhile to put in the SOP" RV added. "You have controls" I said and looked back at the Flt Engineer and Radio Officer to reassure them that all was OK. "It's possible without a problem" said MK with visible relief. "Now we know that 140 tons is safe" added RV, as he flew the aircraft and rolled out Eastwards towards Thoise. With wings level we resumed climbing still on 3 engines, the additional height of 1.3 km to reach 5.6 km was attained well before we reached Khardung La which we crossed and then resumed normal climb on all 4 engines for Delhi.
The main points to be included in the SOP for an overshoot at Thoise were recorded in flight, and the SOP was issued by the squadron within three days and sent for formal approval of HQ CAC and Air HQ. Our trials over Agra had been extremely useful, and a very good guide on how the aircraft would behave during and overshoot at Thoise. All throughout the procedure, the Flt Engineer was ever ready to smoothly increase power on No. 4 engine to take off rating. Bashing open throttles at 4 km could result in a flame out. 44 Squadron was ready for airlifting Bofors or anything else into Thoise, as long as the landing weight was up to 140 tons and the sorties were done at a temperature of +15 degrees C or less. Under these conditions, and with one engine out, a safe overshoot, from a point 6 km short of touchdown, was possible. One other important point included in the SOP was, " In War, and emergency Induction, the AUW limitation can be ignored".
The Bofors Start Arriving.
Illyushin 76 K999 "Zanskar", seen here landing at Palam, flew the first Bofors Gun into Thoise. (Pic Courtesy : Sunil Gupta)
On the evening of 8th May 88, we had loaded one aircraft with the first consignment of Bofors. I had decided that on day one we would fly just one mission of Bofors, later we would fly both aircraft. In K-2999 Wg Cdr Gill and I took off in darkness before sunrise on 09 May 88. Usually, Forward Area take offs are always after sunrise and the first aircraft is designated as the 'weather reece'. We were forced to get airborne before sunrise to reach Thoise when the temperature was less than 15 degrees. Not just that, the AN-32's of 48 Squadron at Chandigarh would start their routine air maintenance after 0800 hrs and we in the IL-76 would be blocking their parking space. Thoise in 1988 was getting an additional dispersal at 29 dumbell. The MI-17s from Base Camp at Siachin would also be returning in the morning. So it was all a very tight fit.
We greeted the sun at 25000 ft over Kanzam La where the source of river Chandrabhagha that then heads westward to Kishtwar. At FL 330 on that May morning, there was nothing over Ladhak except us. For the first time since Siachin erupted, the Bofors were on their way to join the battle. What was happening in India then? A new Army Chief was in South Block. The IPKF was fully embroiled in Sri Lanka. The T-72s had been inducted into Leh The monsoon was not going to fail, and in Sep 88 unprecedented rains would flood much of Himacahal, Punjab and the plains of J&K. The Bhakra Dam would release additional waters, further deteriorating the situation. Uttarlai air base in Rajasthan would get flooded, and vast sandy tracts of Rajasthan would turn green with flooding. 44 Squadron would soon get its last three IL-76's to be handed over to ARC in due course.
The visibility at 33000 ft was unlimited, we could see Sasar Kangri, Sasar Braganza, Nanga Parbat, K2, Nun Kun and a host of other lesser peaks. We gave the weather report to Chandigarh, and as is the responsibility of the weather recce, duly cleared all landing and drop sorties for Leh, Thoise and all DZ's. Soon we were descending towards Tri- Junction. An uneventful approach and landing followed, and we parked on 11 dumbell facing East, with the Outer No 1 & 4 engines running. Buttar got his guns and Scanias out with as much speed as he could. They had to drive straight out and go at least 100 m behind the aircraft before turning left. This was done to avoid the powerful jet blast from No. 4 engine. At Agra we had witnessed a heavy 6 tonner truck just keel over because it came too close to the engine exhaust. After offloading we took on 75 passengers as back load and were in Chandigarh by 0830hrs, ready to load up the next consignment of the Bofors. By 1000 hrs the day's task is over, and the crew would go to meet friends in 25 or 48 Sqns. With temperatures having crossed +15 degrees, it was unsafe to fly another mission to Thoise. A back load of 75 passengers and stores was a God sent boon to the Siachin brigade. The soldiers would be sun-burnt by the ultra violet rays of the sun at 20,000 feet. With no atmospheric dust and other pollutants to filter sunlight, the terrible UV comes unhindered, the fairest of the fair turn deep brown. Ideal conditions to advertise Fair and Lovely beauty Cream for men !
Why Can't You Do What He Can?
On 14 May 88 the last sortie with Bofors 155 mm guns landed in Thoise. Papa Bty of 285 Medium Regiment was ready to join the Siachen battle. Some guns were already on their way to the bottom of the glacier positioning themselves among the terminal moraines to give unerring fire support to the Indian troops fighting on that river of ice. The IL-76's would invariably be airborne by 0630 and by 1000 hrs or 3 1/2 hrs later in Chandigarh we were loaded, ready for the next day's sorties.
On one such morning the AOC-in-C, who happened to be in Chandigarh, came across to see for himself how this operation of 'Bofors Uthao' was being done. I explained to him all the nuances of max landing AUW, temperature, length of RW, overshoot, turning around. He asked some more questions on the performance of the IL-76 and why the landing weight had to be restricted to 140 tons. I elaborated on the available space in the Shyok valley, the ROC, performance on 3 engines, and so on, and the trials we had done at Agra to determine the overshoot procedures. It was then that he completely floored me by saying, "But our MIG 23's can turn around within the valley at Thoise, what's your problem?" I did not labour the point any further to point out the difference between a single seat fighter with after burners, weighing about 20 tons, and the 4 engined IL-76 weighing 7 times the weight of a MiG 23, and climbing only on 3 live engines. I also did not remind him that the MIG 23 has an ejection seat, we the crew of the IL-76 are fixed assets of the aircraft. We fly with it or go down with it. No options.
Another interesting incident was on day 3 of the airlift. As usual, both aircraft were on ground at Thoise by 0715h and at 0745h I was ready to take off for Chandigarh, Our IL-76 was on 11 dumbell ready for take off, Gill was parked on extension at dumbell 29. Just then we heard a MI-17 on R/T coming in from Base Camp asking Thoise. for joining instructions. He was told, "Keep to the right hand side of the valley, IL-76 getting airborne". There was a pause during which the helicopter pilots must have looked at their watches and the next transmission was "IL-76 taking off, confirm he did night halt at Thoise?" We got airborne, and I waggled my wings in greetings as we flew past the MI-17.
The Bofors with their Scanias are still there. The units keep changing, the guns remain the same. Thoise runway is now a nice long piece of concrete. Yet, the max AUW for landing cannot increase, because the mountain has not become smaller! The IL-76 will climb only up to 4.3 km in the available distance from 6 kms short of 29 dumbell at Thoise, to the point when a Left Hand Turn around 'Birla Mandir' has to be initiated. We have to plan our manoeuvres so that we can negotiate the peaks and valleys safely. The mountains are unforgiving, and they never move.
|One of the 155mm Bofors FH-77B field howitzers that are currently located at the Siachen Glacier|
This article was first published in Vayu Aerospace Review. It is reproduced here with permission.