The February 27 Air Combat – a beginning of the BVR’s end?

The Air Combat of 27^th .February 2019,s significance lies in the fact that two of Asia.s most professional air arms clashed under GCI/AWACS control with clear separation of the two forces under daylight conditions with both sets of crews thoroughly well trained in the use of BVRs. i.e. under conditions ideal for the use of BVRs.

What should have happened would have been an aerial equivalent of the Battle of Midway. i.e. both sides should have lost about three or four aircraft each- that has been what the Brochures were promising. As usually happens the script was not followed. What did happen was one (josh!) flea bitten pilot in a moth eaten Bison went and downed a F 16 with a CCM and it appears he in turn was downed by the F 16’s wing man. Some hold that the F 16 had gone into a “vertical Charlie” and when the R 73 blew the F 16 airframe apart the MiG 21 ingested the debris. It does not matter; There is a grim economics at work in warfare. A  MiG due for the knackers’ yard in the next couple of years downed a 4th generation jet. Unconfirmed rumour has it that “BVR brochureitis” also suffered some combat damage.

The Pakistan Air Force is as “cagey” as the Isr.A.F about admitting combat losses but the PAF makes it worse by publishing “proof” which disprove their claims! This is an old habit. One remembers “pictures” of IAF Hunters going down on flames (taken from a picture in The Aeroplane magazine of happy memory) etc until Pushpindar Singh Chopra of Vayu shot all that down. They were at it again. This time they published a picture of a Hawk that crashed in Kalaikunda about two years ago. If this is the best that the ISI can do, …..!? Kuch sharam to Karo!

They also published a picture of some wreckage that they claimed was from a downed MiG 21/Sukhoi 30. This piece was identified by our correspondents as a part of the F 100 engine of the F 16.  I have a wee doubt. Going only by what I saw on TV the item is definitely a Western aircraft. Engines generally survive crashes rather better than airframes. It is definitely a temperature resistant material. I would suggest thinking along the lines that it is a part of the thermal heat shield they put in between the airframe ,which can tolerate only about 400degrees K and the jet pipe which is never below 1000 degrees K. Without the thermal barrier (my generation would remember the “refrasil “blankets which had a “bubble pack” pattern but similarly bright- the airframe would soften. The rectangular aperture visible in the picture was for the stub axle of the Stabilizer and the fuel dump vent pipe. The finish is far too good to be anything Soviet. They were using end mills on the engine casing and that left scuff marks which dulled the finish and later took on a patina of burnt oil! Russian high temperature materials have a light copper sort of colour. The above is a suggestion. The finish is far too good to be from a Soviet era aircraft or engine!

The AMRAAM missile displayed by the Vayu Sena was interesting. It has been carefully flattened so that journalists could read and photograph the lettering in one go but the question is- was the BVR missile fired or simply jettisoned? If fired the skin would have been exposed to 450 degrees centigrade for almost a minute yet the lettering was pin sharp. Also the casing is pretty intact for something that impacted at Mach3. So were they simply jettisoned to clean up the aircraft and get out of trouble?

The above  is plausible because at low level –“head on” the “firing window” is strictly limited with a effective range of perhaps seven or eight kilometer and a closing rate of 0.5 kilometers per second. The detection range of the radar is also severely affected and hampered by terrain masking. The work load for the crew may be just too much.

The success of the Bison was also due to it being the simpler aircraft , which, like the Gnat,had a smaller “wind up” time and so was able to launch and be in the right position at the right time. It was of course very daringly flown by an obviously well trained pilot. It is reassuring that the AF is, as always before, in great professional hands.

The questions that arise are

i)                    This was an ideal case for the BVRs. What prevented their effective use?

ii)                  The conditions of the engagement are what we will get for most daylight hours for most of the year. How often did our crews use their onboard radars during this engagement?

iii)                What were the performance /positions/likelihoods of the other platforms to have scored and what were the reasons for their (relative) lack of success?

Could it lead to are-examination of our day fighter specifications? Any equipment not needed in the combat is a handicap in winning that combat. The value of the February 27^th engagement is that it is a reasonable sample for analysis by the experts.

Prodyut Das

Creating an Indian Weapons Industry -the combat in the shadows

Any discussion on the development of the Indian Weapons Industry tends to focus on the technical problems. This distracts from discussing the fundamental problem. India has an inefficient weapons Industry. We import 70% of our weapons needs. This unacceptable state has been caused by our continued espousal of a Socialist pattern of Society for the defence industries. The process of weapons development are choked by the legacies of colonialism, the overrunning of our education systems by the politicians and by the sustained refusal to organize our defence industries as a highly specialized and competitive industry that should be self financing. The combat is in the shadows.

The exorbitant costs

 Countries with large forces “afford” them by developing weapons and exporting them at very high profit. We have for long not exported any weapons, ostensibly on “moral” grounds of “non violence”. Our abstinence has not stopped violence; We have merely ignored the economics of successful weapons Industries. The HAL produced LCA Mk 1 A will cost Rs.483 crores apiece. This makes it weight for weight, the most expensive single engine aircraft in the world beating the Lockheed-Martin F 35. Clearly something is amiss.

The  production cost of any imported weapon is a closed book to us. We only know the quoted cost. No authorized study exists about how much it costs the vendor to make the product. The inefficiencies of the PSUs mean that their prices are not a reliable index. The development of a database by which we can estimate the cost of production of any imported equipment is an immediate requirement.

A modeling of the comparative cost

The basic of calculating comparative costs vs production quantitites however is very simple as the following model will explain. The cost of an aircraft depends on four inputs viz:

i)                    Raw materials (RM) costs – sheet metals and rolled stocks, Composites, forgings, etc.

ii)                  Bought out Completes (BOC) such as engines, radars, accessories, cabling etc.

iii)                Labour to process and assemble. The cost of labour is the largest single item of cost of an aircraft in western countries.

iv)                Overheads which is all other costs required to run this programme.

If we now make a simplifying assumption that the four components RM, BOC, Labour and overheads are all equal with the overheads assumed at a production rate of 50 aircraft per annum and an order size of 500 aircraft then we get the unit cost of an aircraft comes as 4x which we take as the comparator cost of 1 unit. Table 1. Sl. No. 1

The production rate of fifty aircraft per annum and a minimum order size of 500 is the minimum numbers for a competitive commercially successful weapon such as combat aircraft and AFVs. Beyond these numbers are massive profits. This minimum number is essential and explains the cut throat competition for export markets and our need to export.

If we now produce with the above set up only 12 p.a. aircraft as is being done for the LCA and the order size is about 100 the costs go up 1.8 times.   See table 1. Sl. No 2

If the production is cranked up to Chinese standards of say 100 aircraft per annum and an order size of 1000, we see a remarkable drop in the unit cost to 0.675 or about one third of Indian costs. Table 1. Sl no. 3

The above is assuming that only the aircraft assembly line utilization has been optimized. If we assume that the same process has been applied by the Chinese to the production of Raw Materials and BOC items we get a figure of 0.4854 or one fourth of our costs! Despite much larger size the Chinese equipment budget for their massive armies may not be much larger than our equipment budgets.

We have willingly allowed ourselves to be fettered with is the continued use of “bonded” or “Aerospace” quality materials which means “de facto” a reliance on materials imported from the West. “Bonded” items were an useful concept a century ago when QA processes were uncertain. Metallurgical quality control systems have been sufficiently improved and automated over the last hundred years to allow our designers to specify materials from selected Indian vendors but not confined to the PSUs. This is an area where the politician must enforce because the Bureaucracy will not because they have nothing to lose by doing nothing.

The extremely long development times makes the interest cost of the capital untenable. That cost alone will make our weapons unaffordable to us, let alone for exports!

 The impact of production volumes has been discussed. Unless we re-examine and increase both procurement and batch sizes we can never have acompetitive weapons industry. It will be as it is now a “naam ka wastey” –( eyewash) effort nowhere near its true potential of being a niche world leader.

Table 1.

Sl. No.	Model	Raw. Material.	BOC	Labour	Overheads	Total	Unitized
1.	Standard 50/500	X	X	X	X	4X	1
2.	Indian 12/100	X	X	0.2 X	5X	7.2X	1.8
3	Chinese 100/1000	X	X	0.2X	0.5X	2.7X	0.68
4	Chinese optimized	0.68X	0.68X	0.2X	0.5X	2.06X	0.48

XX/XXXX Annual Batch Size/ Total order size.

 Organizing Academia’s contribution

Exporting Defence equipment will require not just technical research to produce fault free weapons but also historical and economic research to manage and market and service them and trained workers to produce them to high quality. The word “Unemployability” indicates how badly equipped our Academia is equipped at present for the task.

 We have 819 Universities and in term of numbers we are not at a disadvantage. Research funds are also not a problem because well directed research is rapidly self regenerating. The problem is in the quality of our Academia and its lack of orientation and training to engage in applied research specially in hardware. The 1969 thrust towards publications “publish or perish” has to be reviewed as the faculty finds it career wise safer to publish theoretical papers in numbers.

It was not always thus. Derided as being designed to produce clerks for the Empire the British set up in India an education system that was once rightly vaunted to be second only to Oxford and Cambridge. Almost from the start the Indian Universities produced an unbroken stream of exceptional leaders in every field. Though the study of the Sciences was not encouraged Radio Telephony, the Raman effect, the Crescograph, semiconductor junctions, the Bosons were right at the forefront of Technology and Science and indicated the highest levels of originality and these were done with modest, if any, grants. Such brilliant work required an intellectual uprightness and boldness coupled with originality. Unfortunately the cradle of such minds- the schooling system- has also been thoroughly vandalized.

It is well known that our top universities do not rank anywhere in the list of top 200 Universities. Various suggestions to improve rating have been made. They are unlikely to work. An example will clarify. The number of foreign students is one of the inputs in the ranking process and hence “efforts will be made to enroll more foreign students”. The cart is truly before the horse. The foreign students do not come to Indian Universities because they see no value addition. That has to be corrected. Enticement will not work.

The problem lies in that it is inconvenient for those who can rectify the situation- the politicians and political-academicians- to admit that it was their collaboration for partisan aims that has ruined our universities. In their “suggestions”- academic freedom and more funds- they therefore studiously “fail” to see that the top two hundred Universities in the world do not see the rampant, disturbing, perennial publicity seeking academic activism that our Universities and campuses have unendingly seen on various non academic issues.

The lowering of every long established academic standards- entry, recruitment, qualifying- post independence is unique and not done by any nation anywhere. The solution lies here. The original, impartial, exacting standards of education and the intellectual and fiscal honesty in Academics has to be restored. A return to status quo ante has to be aimed for. Academic freedom is not a license.

 The origins of the concept of “Academic Freedom” lay in the fact that it was the Church that funded the Universities and so the Church made the rules. For example the Professors were not allowed to marry. The State did not fund and was not allowed to enter the gates. He who paid the piper called the tune. Our political academics claim for the “leave the money on the table and go” variety of freedom from the state has no historical or moral basis.

 As with other welfare schemes since independence the increased funding for education has “leaked”. The resistance and organized outrage to what should be routine administrative matters such as introduction of biometric attendance or audits of funds are noteworthy. It could be an indication of the scale of leakage. Audits which would ensure funds are used as intended may have the side effect of a reduction in the kind of demonstrative academic agitation that is seen.

Post Independence economic policies

The history of the economic policies of the Government, post Independence has to be re-examined for its lessons. Why was an inefficient disempowering centrally controlled economy put and kept in place for so long. It is unarguable that there was significant improvement in standards of living after the previous crippling license permit policy collapsed due to its own inherent weaknesses why was this not applied more vigorously and more transparently to the strategic Industries? Were we under superpower pressures or pawns in the continuing great game? “The strategic Industries, being knowledge and passion Industries were particular sufferers.

The espousal of a “socialist pattern of society” in the garb of welfare had several “anti Indian Industry” measures:

i)                    In the early fifties a Parsee gentleman had designed and built two prototypes of a glider, the Baroda 001 & Baroda 002 which was significantly in advance over the Government department’s glider which was a copy of the German “Zogling” of the 1930s.The Baroda design was not produced. In all probability the Industrial Policy resolution and the stifling License and permit procedures killed off the effort. By 2006 the Baroda 002 was slowly “reducing to produce” in a workshop shed, an incredible-and unique-symbol of state sponsored Industrial repression. It was not the only example. A Calcutta firm had worked towards a collaboration with France to make the Djinn light helicopter which had a particularly good high altitude performance. This too got nowhere.

ii)                   Whilst Tata and Ashok Leyland were already making trucks for the Army public money was spent- to acquire a new line to make the Shaktiman Trucks at Jubbalpore. The result was the economies of scale were frittered away. This is precisely the kind of wastage of resources that the centralized planning was supposed to avoid. This was at a time when the HF 24’s engine was refused a grant of GBP1million for its critical engine -due to “shortage of resources” which crippled the HF 24 programme. We have to ask why this was done. The technical differences between the three trucks were marginal and within the development capabilities of the local Industry even at that time.

iii)                 One side effect of the “license permit” Raj was the total lack of design & development jobs for the engineers the IIT were producing. Those who did not migrate to the US spent their careers selling soap and toothpaste for the multinationals in India.

iv)                 The Defence sector PSUs jobs were significantly less paying with the worst working terms as compared to other state enterprise jobs such as EIL or STC or the Bureaucracy.

These are either random errors of policy or indicate a crafted plan that protects monopolies. We have the irony that in defending the socialist pattern of society, in the PSU unions de facto right to be inefficient and in espousing an Academic “freedom” of the above sort we are collaborating for the continued crippling of India’s strategic Industries.

Funding Defence Research

Successful Research is always and everywhere viewed as a business. Research funding must pay back by a return on the investment within a reasonable time because only then will a corpus of fund build up. Complaints of inadequate funding for research go hand in hand with misdirected research project without any plan for commercialization.

American funds availability for research is large because they are controlled to be self generating. It is run like a venture capital funding agency-closely monitored for returns. In India the stress on “return on investments” is completely missing. Because of our leftist oriented doctrine and controls the private sector cannot be funded but though regularly scam ridden it is “safe” for the bureaucrat to fund the PSUs even after several scams. The result is influential people obtain public money for what becomes, de facto, a life time sinecure. Such wastages lead to non performance and the consequent lack of regeneration of funds creates a”drought” which hampers further research funding.

The example of DARPA which funds defence research in America should be a model.

DARPA fundings are ALWAYS for short limited objective projects –the first usually being measured in months.. This is enough to show progress and results. The advantages of this approach are:

i)                    Initial funds are for very small amounts even for big projects. This allows funding of many concurrent and even competing proposals.

ii)                  The private sector has an equal right to public funds

iii)                The initial project duration is often as short as six months. Like the bankruptcy laws ,the “imagination wise “bankrupt groups” were quickly identified and weeded out leaving the funds free to flow back and be re-invested elsewhere.  

iv)                The “residue” of the above project, if successful, is funded to the next step or level until a saleable product is results. The F 117 stealth fighter was developed into service in a period of eight years (1974-1982) on a funding level at PPP (purchasing power parity) of 3.5 lakhs/ 3.56 crores/117 crores.  Interested readers may see “Developing the Stealth Technology”  earlier in the blog profprodyutda@blogspot.com.. By comparison we funded Rs. 565 crores in 1983 on a ten year plan to a yet to exist entity to develop the critical fighter programme- The LCA. Illogically a 1978 request for Rs. 64 crores funding to develop the HF 24 with RB 199 engines which had a higher chance of success was turned down. These illogical decisions must be re-examined for their thought processes and the appropriate lessons absorbed. Given our experience with the LCA programme, the minimum now expected is that any future project AMCA or New MBT should be a 3 step programme and with private sector proposals also equally funded.

We cannot afford to continue to ignore the private sector and there is no justification! The PSUs have seen as many scams  as we can wish!

    

  Counter Intelligence

 Knowledge leaders are especially precious because they are rare and they take a lifetime of dedication to produce. India has an history of being remarkably careless of its HR assets. Homi Bhaba, Vikram Sarabhai, the scientists associated with the nuclear submarine projects and the Arjun tank’s engine, the test pilot who was an enthusiastic proponent of the HF 24 “reheat” project died under doubtful circumstances yet the investigations to their deaths were significantly cursory. The failure of ISRO to stand by its expert in Liquid propulsion engines when he was falsely charged with espionage wrecked his career. The expert was later exonerated but the desired damage- delay of our ability to compete commercially in the satellite launch market by fifteen years- was achieved. The common courtesy- given unstintingly to felons and politicians – that a man is not guilty until legally proved so- was denied to this scientist. Surprisingly, in the Soviet Union where sometimes failure meant facing the firing squad, the key scientists were “imprisoned”  in their work places. The question is why this was not arranged? The final gall of the ISRO episode it appears is that the police officer who caused such damage to the nation was “pardoned” scot free when the charges against the officer were dropped by a Chief Minister. Chairmen of HAL who supported strongly local development were removed, sometimes unceremoniously. A particularly active Chief Designer was retired promptly whilst non performers have been given sinecures. Again the US is a model for the way they attract, develop and retain human resources.

Knowledge is a precious resource; it takes a life time to develop. Suitable security protocols must be developed along with discreet surveillance of all personnel. It is remarkable how effective how even routine and non intrusive surveillance of a few key parameters can be.

Defence as a Business

A weapons Industry is a high risk high profit “full time” business. . It requires all the time, dedication, energy attention, knowledge and efficiency such a business needs.  In the Totalitarian states it was possible for “the man in charge”- e.g. Admiral Gorshkov- the father of the Soviet Navy’s renaissance to stay at the helm for thirty years and was retired only at his own request. As a senior “cabinet minister” and political leader he combined job knowledge, national policy and clout in one person. The result was that the Soviet Navy became a challenge to the mightiest Navy, the USN. This is not possible in Western Democracies so they, recognizing reality, hand over the knowledge, passion, and day to day dedication required to run the business to the private sector with the state as an Investment Banker and Salesman- to wit the number of state visits to sell this or that equipment. An example of how western democracies work would be to study the operations of the firm of Marcel Bloch which is better known as GA Marcel Dassault the new surname being the nom de guerre of his elder brother.

Marcel Dassault (1892-1986) started as a propeller manufacturer during the First World War and went on to manufacture of aircraft during the 1920s. Renaming himself after the Second World War( and after a stint in a Nazi death camp for Jewish people) he went on to lead General Aeronautique Marcel Dassault, one of the most innovative of aviation firms which achieved brilliant results using fairly basic technology with great elan to create fighters which became household names and considerable profits for the shareholders. Marcel Dassaults passion was so great that as long as he was alive apparently he did not allow his worthy successor and son, Serge, to run the company! Between the two we are seeing acentury of continuity, job knowledge and passion. A Bureaucrat, no matter how astute, on three year tenure from the Ministry of Animal Husbandry or Mines, just cannot do it. The odds are entirely against him.

The story is of passion, dedication, and continuity. I could have cited Sir T.O.M. Sopwith, Chairman of Hawker or Donald Douglas but I have deliberately chosen Dassault and France because France was the European country most affected by leftist ideals and communism and yet the French communists were knowledgeable enough and pragmatic and patriotic enough to realize that certain areas were beyond their skills. When they nationalized the French Aviation Industry they were pragamatic enough to leave Marcel Dassault in charge of the Bloch plant. The time to continue with unworkable political theories is long past. The industry is too dynamic and knowledge based to be effectively managed by the present set up- and the results show repeatedly.

Conclusions

The continuity of Socialist policies in the strategic Industries –Aerospace, Defence- have to be re-examined because we have a crisis because of the past policies. Programmes have missed every deadline ever set. The strategic Industries do not respect political theories. These are knowledge Industries and are amongst the most dynamic and creative of all Industries. Countries on both sides of the political divide despite general posturing have recognized this and organized themselves accordingly. Only we ,for reasons unknown and suspect persist with a failed and increasingly decrepit system.

For India the best course will be, was elsewhere, to give the private sector the leadershipin te strategic sector with the Government in the role of a venture capital source and in Marketing which is the universal model everywhere.

The West’s monopoly over all Industrial goods of a hundred years ago has been taken over by the Far Eastern countries who, significantly, offered a better product at breathtakingly lower prices. Weaponry is the last bastion for the West and they will defend it by all means, not necessarily fair.

In our liberalization in the 1990s the areas “liberalized” were only those which were already lost to the West. Weapons production and development was retained for the PSUs despite the presence of many scams and evidence of inefficiencies.   

A functioning world class education system has been vandalized to “unemployability”.

The vilification of the Private sector-even from before Independence- as being unworthy and untrustworthy to receive Public funds for weapons development has proved unjustifiable. Despite a continuing list of PSU scam these are indulgently patronized despite shocking irregularities.

India’s democratic government is the only one in the world which treats its weapons Industry as another Government department no different in its style of running from say the Ministry of Labour.

License restrictions, muzzling of effective research, non funding of promising projects, sustained funding of projects that are not producing the desired results are the rule.

We can treat all of the above as random unconnected events or we can see it as a carefully planned scheme to protect weapons import monopolies. Whatever may be the truth it has hurt our Defence industries and our preparedness. The combat is also in the shadows.

The Saras PT 2 VT- XRM Accident Report- A note of dissent. Prof. Prodyut Das

Whilst collecting material for a feature on prospective Indian Civil aircraft I came across the DGCA report “The Final report on the investigation on the accident to the NAL Saras PT2 aircraft VT-XRM at Sheshagirihalli near Bidadi’ Karnataka on 6^th March 2009” report dated  6 December 2009. The full report of 75 pages is available at dgca.nic.in/accident reports. I understand that there are no other reports available to the public.

I am uneasy with the findings of the report and its recommendations because of the following:

i)                   The report does not explain the type of wreckage or the wreckage “foot print”.

In addition the report does not seem to have investigated the following:

ii)                 The configuration of the aircraft ( rear engine T tail turboprop)

iii)                “deep stall”

iv)                flat spin”

v)                  The possibility of the CG position of the aircraft having travelled beyond the rear CG limit.

Without having investigated and ruled out the above possibilities the report may have drawn erroneous conclusions and corrections.

If my prognosis is correct the aircraft may crash again if tested under the suggested corrected test parameters.

Unfortunately the report does not contain the data needed for me to check my own apprehensions. Since the Saras test flying has resumed I am taking the risk of publishing my views for a wider discussion.

Introductory Glossary:

The rear engine twin turboprop configuration:

The engine, nacelle, propeller and mountings of this class of aircraft- twin engine light commuter- is around 15% of the mass of the aircraft. If such a mass is located at the rear, as in the Saras, the CG moves backwards by a considerable account.

To “balance” the aircraft for stability the wing has to be moved back. This reduces the tail moment arm significantly and it is normal for this configuration to have either reduced yaw and pitch stability or have larger keel (fin) and stabilizer areas so as to maintain “tail volumes”. The lateral stability is worsened by the fact that there is a larger “Side area” ahead of the CG further reducing the yaw and pitch stabilities.

The location of the undercarriage is more sensitive in a rear engine layout. It can affect the stabilizer sizing (by about 30% in one case). However there is no evidence that this aspect played any immediate role in this accident and is therefore not being further discussed here.

The spin

An aircraft if yawed at near stall speeds it will inevitably flick into a spin. It happens as follows:

The aircraft is flying straight and level at near the stall speed. If yawed, say as in this case, to the left the left (port) wing’s airspeed falls and it generates less lift. This causes the wing to dip which increases the angle of attack of this left (port) wing. It is now well and truly stalled. The wing is past the inflexion of the Lift /Drag curve and so it generates less lift and more drag. Exactly the opposite happens to the starboard (right) wing. The entire wing is now subjected to a rolling couple (because of the different lifts) and a yawing couple because of the different drags. The aircraft becomes uncontrollable because of the low airspeed which makes the control surfaces forces much less than in normal flight. Recovery happens by diving the aircraft- to get the entire wing “flying” again- and correcting the yaw. A spin is a frightening situation to be in and requires preparation and mental “psyching”. Due to the lower moment arms a rear engine aircraft takes longer to recover from a spin.

Deep stall

At stalling speed an aircraft is at around an AOA of 15-18 degrees. This may increase as the aircraft begins to sink due to loss of lift. In a rear engine aircraft with a T tail the disturbed airflow past the engine nacelles “hits” the stabilizer and reduces its effectiveness partially or completely. The pilot is unable to pitch the aircraft nose down to recover from the stall. The BAC 111 prototype accident in 1963 brought this phenomenon to public attention. The Deep stall is peculiar to the rear engine layout.

The alternative construct of the accident

The starting point of this hypothesis is the examination of the impact point and the description of the wreckage:

1.      The ground is hard and stony. The wreckage should have slid along and formed the usual “wreckage trail”. This has not happened.

2.      An aircraft has fallen out of control from a considerable height (about 7000’). The scatter would have been like that of a bomb explosion with an elliptic/asymmetric scatter of debris.

These are not reported.

3.      It is reported that all the components are within a 20 mts. radius of the wreckage i.e. hardly greater than the wing span of the aircraft. This was caused by the fuel tanks exploding and not due to kinetic energy As reported rightly, this indicates there was little or no forward speed.

This type of the wreckage “footprint” happens when the aircraft has crashed whilst in a flat spin or deep stall or if the aircraft CG has travelled beyond the rear limit.

How did the spin happen?

The aircraft as per report was at around 132 knots at the beginning of left engine shutdown. The speed decayed further due to additional rudder trim drag and due to lower power from one engine. At the beginning of the engine restart point approx -1.32 minutes time before the impact the speed was around 120 kts. At that altitude and at the probable then weight of the aircraft the stalling speed was around 115 kts.

When the propeller was accidentally unfeathered, the asymmetric drag pulled the speed down close or below the stalling speed and also yawed the aircraft. The spin then became inevitable.

The spin then developed into a flat spin which was probably mistaken by the crew as a (momentary) recovery. If the aircraft was in a normal spin it would have impacted “nose down”. This is not indicated by the wreckage. Recovery from a flat spin is impossible. The crew did not have a chance.

Deep stall

According to the report the aircraft was losing height at 10,000 fpm. This works out to around 95 kts. The IAS of the aircraft had (to be noted) further decayed to around 110 kts. The relative wind was in the order of 60 degrees. Even if nose down pitch angle is considered (the report is not clear on this) the aircraft was definitely stalled and the stabilizer was in the disturbed air of the nacelles and therefore ineffective.

Rearward shift of the CG.

The pilots repeatedly complain about the excessive drag. The Saras aircraft is not per se a “draggy” layout (note 1). From the TO weight given the aircraft was not ballasted for the passengers. In a rear engine layout this results in the CG moving back. It is quite likely that the CG had started at a very rear ward position and as the fuel was consumed it moved further back beyond the permissible limit. This made the aircraft uncontrollable. An aircraft out of trim- like a car being driven with the parking brake “on” will feel “draggy “and be ready to depart control. This condition can demonstrated easily and simply.

Other factors.

1.      The pilots had over 2000 hours experience but less than 300 hours on turboprops. They were likely from the fighter stream. Test piloting is a precision engineering job.

2.      The aircraft had a three lever engine/prop control unlike the usual two lever system. This particular test required instant and instinctive reactions as well as utter familiarity with turboshaft engines- preferably not even turboprop. The Crew( apart from the Flight Engineer) were not suited for this task ( Note 2)

Conclusions:

The aircraft crashed due to problems associated with the layout, deep stall and a too rear position of the CG or a combination of all three.

If the test is repeated at the same speed but even with 15000’ AMSL altitude recovery from uncontrollability is not certain. The low speed close to the stall was definitely a factor.

The verdict of pilot error is to be reviewed and downgraded.

Recommendations

1.      The spin recovery and the deep stall characteristics of the Saras needs further study and revalidation

2.      It is presumed that prototypes were under 24X7 CCTV surveillance and monitoring. Prototype security on the ground is mandatory and standard assumption in accident investigations. IF not unauthorized tampering and or sabotage cannot be definitely ruled out.

3.      The behavior of the two pilots prior to the start of the tests, the wrong reporting of heights etc and the decision to press on despite misgivings of all three needs further investigations. It is presumed that the post mortem included checks regarding absence of harmful medication.

4.      The verdict of pilot error needs review. They were not briefed about the possibility of the aircraft spinning. Any flight test plan should be subjected to “Failure Mode Analysis” so that pitfalls are not overlooked. The failure to anticipate the possibility of proximity to stall speeds at 10,000 feet is worrisome.

5.      The report should include, in tabular form, the aircraft attitude parameters, the altitude and the control deflections, particularly for event after -1.36min.

6.      It should be mandatory that any crew member can order abort of a sortie and return to base for debrief and check. It is cheaper and faster than accident investigations and building another prototype.

7.      A sortie cannot depart until all instruments and sensors are tested for uniformity of readings.

If the root cause of the accident is not correctly identified then these men have died in vain.

Note 1.

There is no reason to surmise that the drag reported by the pilots is inherent in the design. Some views have been heard that the fuselage diameter is too large for the aircraft and that the wing aspect ratio is too low.

The fuselage L/D ratio is around 7.5:1 and is suitable for this class of aircraft and speeds.

The aspect ratio of about 8:1 is standard practice for Russian designs who use this even in their long range bombers. Interestingly the Americans use around 11:1 and suffer from structural fatigue problems. The C5A Galaxy had its entire wing replaced in most airframes and the B 52 has had so many “Band Aid” patches it is claimed that the airframe carries its own weight in these reinforcement patches. Since induced drag is a reciprocal of AR the Russian approach is technically more correct. This is a personal opinion.

Note 2

Flying safety requires quick reactions to the point of being instinctive. Wg. Cdr. Guy P. Gibson V.C.  the legendary bomber pilot of the RAF died in a crash of the DH Mosquito aircraft to which he had recently converted and was out of practice. It is surmised that when one of the fuel tanks ran dry and the engines cut delay in switching tanks because of his being out of practice may have caused the fatal crash.