http://www.stratpost.com/how-many-engines-for-the-mmrca
Xcpts:
How do you compare the cost and reliability of a single-engine aircraft with a twin-engine aircraft? It seems obvious that single-engine aircraft would be much cheaper to buy and maintain, especially in terms of life-cycle cost, and that the reliability of twin-engine aircraft would exceed those of single-engine aircraft.
And if the IAF gives no extra points for performance exceeding the ASQR parameters laid down, then a decision on selection could rest solely with the MoD judging the commercial bids, where single-engine fighters would have an edge in terms of pricing.
Or would they?
The Austrian decision on the purchase of fighter aircraft is an interesting study of how a unified measure of the cost of the two types of aircraft with respect to their performance can be quantified.
The Austrian Court of Auditors examined the award of a contract for the supply of 24 Eurofighter Typhoon aircraft to the Österreichische Luftstreitkräfte (Austrian Air Force) in 2004, which had been competing with the Swedish Gripen for the order. The court looked at the process their Austrian Ministry of Defense used to arrive at a cost and utility analysis of the two aircraft on the basis of a mathematical model.
The court scanned the process their MoD used for gauging the operational capabilities of the two aircraft — what the report refers to as ‘the military benefits of an aircraft’ or what it means in a fight. Weightage was given to different criteria of performance (range, payload etc), which were tabulated and summed up out of a maximum cumulative weightage of 1000 points. The Eurofighter Typhoon scored a little higher in terms of the weightage given by the Austrian Air Force for performance with respect to their requirements.
The report says the auditors, evaluating the result of the Austrian Air Force and the MoD, found that weightage given to 35 performance criteria required adjustment, which resulted in a further shift of the cumulative weightage in favor of the Eurofighter Typhoon.
The relationship between the respective costs and the military benefits or operational performance of the two aircraft produced the cost benefit/utility analysis, which was a quantification of military benefits and what they cost. The cost benefit/utility analysis reflects the quantification of benefits with respect to their costs. The Austrian Air Force was looking for the maximum capability at the best price, or the ‘best bidder’.
In case of payment on delivery or in ten equal half-yearly annual installments Gripen offered the better deal. In case payment were made in 18 equal half-yearly installments, the Eurofighter Typhoon offer was better.
But the unit price for the Eurofighter Typhoon wasn’t necessarily lower than that of the Gripen. What the court validated was the judgment of the MoD that the offer for the Eurofighter Typhoon was more attractive, considering the payment model being offered for the performance criteria matched by the aircraft. While the Eurofighter Typhoon offer was higher than that of Gripen if payment were made on delivery or over ten half-yearly installments, the cost and utility analysis of the Eurofighter Typhoon offer was a little less than Gripen’s quote, if payments were made in 18 half-yearly installments.
What’s also interesting is that the offer made by the Eurofighter Typhoon consortium for 24 aircraft by payment on delivery wasn’t all that much higher than the offer made by Gripen (the order was later reduced to 18, and then, 15 aircraft). This, in spite of the fact that the engine in a fighter is often considered to make up around one-third of the value of the aircraft.
But at the same time Jane’s has reported a different scenario in the ongoing Romanian process for acquisition of 24 fighter aircraft, with Saab ready to offer 24 new Gripen aircraft at a cost of EUR 1 billion, against 24 second-hand Eurofighter Typhoon aircraft (and also, 24 second-hand F-16 aircraft) being offered at the same price.
It must be noted the costs considered by the Austrian Air Force and Ministry of Defense were not life-cycle costs, as India is going to adjudge. The costs are the offers made for the aircraft, in addition to weapons systems and other support systems. Nor does the report mention the performance criteria which were weighed in tabulating the cumulative military benefits of both aircraft. Each performance criteria may also be weighed differently and indeed, Indian requirements may well be very different.
But at the stage of consideration of the commercial bids, will the ministry also look at issues such as the opportunity cost in the event of a crash of one of these aircraft? “If a single-engine aircraft loses an engine, say in the event of a bird hit, the IAF loses the aircraft and possibly also the pilot. If a twin-engine aircraft loses an engine, the IAF loses an engine, which can be replaced,” says the representative of another vendor in the contest. But single-engine fighter aircraft vendors claim that engines in current twin-engine aircraft have very few failure modes that allow an engine to run in case the other fails and that they are so closely fitted that an engine down due to bird hit or weapon strike would probably result in an explosion, causing the other to malfunction.
Most aircraft in the MMRCA competition are fairly recent developments and do not have an operational history lengthy enough to get an idea of their reliability in terms of the number of their engines.
The United States Air Force (USAF) figures tabulating engine-related Class A mishaps for single-engine and twin-engine aircraft tell an interesting story. Class A mishaps are those where the total cost of damage is $1 million or more, and/or involves destroyed aircraft, and/or fatal injury, and/or permanent total disability. The USAF Air Safety Center has tabulated charts up to March 31, 2010 and, in general, the rate of engine-related Class A mishaps is higher in single-engine combat aircraft than in twin-engine aircraft.
. They have no option but to resort to other means to convince the MoD to keep them in the running.