Analysis of Peacetime Attrition of Historical IAF Aircraft

anil chopra, air power asia, Indian Air Force, Aircraft, Flight Safety, Attrition

As a long term, non military observer of the Indian Air Force for over 50 years I believe I have a unique outsider’s perspective of the Air Force. In this era of social media the number of military aviation enthusiasts and followers can be seen to be enormous, but up to the early 1990s observers of the Indian Air Force in India had virtually no sources of information apart from the occasional news snippet or blurry photograph. Foreign aviation magazines were either unavailable or unaffordable. But after the late 1990s and the advent of internet access in India, information exchange became easier and the average person who was fascinated by combat aircraft could start talking about what was happening.

MiG 21 BiS. Image Source: keralakaumudi.com

This period coincided with the MiG-21 being the dominant numerical type in the Indian Air Force and reports of MiG accidents received more than their fair share of media attention. Most often, neither the public nor the media knew the difference between  MiG-21, 23 or 27. A MiG was a MiG was a MiG. Even a Mirage or An-32 was a MiG. From this grew the idea that the MiG-21 was a flying coffin, an unfair description, as I will demonstrate in the following paragraphs. With the public and the media fighting a vicious war against the MiG-21, it was odd to see the love and praise that was showered on the venerable MiG-21 from pilots who actually flew her. A number of veterans wrote laudatory articles about the MiG-21. Off the top of my head I can recall articles by ACM Tipnis (retd) who reminisced about his faith and love for the MiG-21. Another was from late Wing Cdr. Kukke Suresh (retd) who explained some flying characteristics of the MiG-21 that could lull an unwary inexperienced pilot into a sense of safety in a dangerous situation. More recently ACM Dhanoa (retd) showed his confidence in the MiG-21 by flying sorties just prior to his retirement. So there was a clear divide between public condemnation and the words of pilots who actually flew in their machines.

HF 24 ‘Marut”. Image Source: indianexpress.com

From the late 1950s to the present day the IAF has flown more than a dozen jet fighter types, but the MiG 21 got the reputation. So I wanted to see if I could dig into the history of various types operated by the IAF to compare their record of peacetime accidents in the IAF. Most lay people, including many who describe themselves as being interested in military aviation do not know the difference between flying a high performance military aircraft and a civilian jetliner for an airline. The fact that there is an inherent risk in flying combat aircraft escapes outsiders. The physical stresses of flying a combat aircraft, the need to fly at night, at low levels, in poor weather, at high altitude through clouds, between invisible mountains, or just meters off the ground, almost scraping trees are unknown to anyone who does not fly a fighter jet. Many people compare jet fighters to cars and do not realise that even the machine itself is subjected to physical and thermal stresses that far exceed what the fastest race cars need to cope with. Thus, lay people often do not understand that there is regular attrition, or accidents, involving fighter aircraft all over the world for reasons that could range from equipment failure to human causes. Despite the best efforts of any air force, accidents do occur.

Gnat Aicraft. Image Source: Pinterest, flying-tigers.co.uk

My idea was to compare the accident statistics of historic Indian Air Force aircraft to see if there are any patterns or anything for the layperson to learn. For this I was aided by two things that I must acknowledge. The first is the fact that the IAF does not hide its losses, unlike some of our neighbours. The second is the superb database of Indian Air Force types and accidents maintained by my friend PVS Jagan Mohan on www.bharat-rakshak.com. Most of the data I have used in this analysis has been taken from Jagan’s detailed database. I decided to use only the data on aircraft that have been retired, except the MiG 21, which cannot be ignored. Here is the table that I generated. (Figure 1)

Figure 1

Aircraft TypePeriodYrs. in serviceTotal aircraftNumber lostWar LossesPeacetime loss
Vampire1948-1975273861011190
Ouragan1953-19671411338038
Mystere1957-197316110432221
HF-241967-19902314728424
Hunter1958-1996382521193782
Gnat/Ajeet1958-19913326288979
Su-71968-198618140451926
MiG-211963-5884328514271
MiG-231984-20072316248048
MiG-271985-20193416557156

For the purpose of the analysis I decided to exclude all wartime losses to arrive at a number for peacetime attrition, which is shown in the last column on the right. The cause of these losses is rarely made public, and that will not be the subject of my analysis though I will touch upon it briefly. Even the figures in the table may be approximations in some cases as the detailed numbers and dates are not consistent across sources.

Figure 2

Figure 2 simply charts the numbers of aircraft historically operated by the IAF. The MiG-21 exceeds all other aircraft by a huge margin. This has been stated as the reason for MiG-21 accidents getting the most media and public attention. Figure 3 graphically shows the total number of each aircraft type lost in peacetime accidents, and once again the MiG 21 heads the table.

Figure 3

But a question that arises here is whether the MiG-21 was also an unsafe aircraft which was unfortunately inducted in large numbers? In order to address this question objectively we need to look at the number of years an aircraft was in service and then see how frequently numbers were getting depleted by accidents.  Figure 4 represents the number of years that each type was in service. The MiG-21 of course is still in service after 58 years

Figure 4

Figure 4  charts the number of years of service of each aircraft type. Here again, the MiG-21 tops the list , but we can now see an interesting pattern emerging. In every graph, from Figures 2 to 4 the first five aircraft are MiG-21, Vampire, Hunter, Gnat and MiG 27. These five served in the largest numbers for the longest periods of time and suffered the most peacetime accidents. But we still don’t know which aircraft had the worst record during its period of service. Was it the MiG 21 or some other aircraft?

For this, I calculated the percentage of aircraft (from the total in service)  of each type that were lost per year of service. Simply stated this means that if any aircraft type lost 10% of its initial total every year, then in ten years 100%, or the whole fleet, would have crashed.  This gave a very interesting result, shown in Figure 5.

Figure 5

Figure 5 shows that the Ouragan lost, on average, 2.4% of its original numbers in every year that it served in the IAF. This is the highest attrition rate. And interestingly, the MiG-21 comes at the bottom of the list as the safest and least accident prone type, with a peacetime loss of just 0.55% of the total number of aircraft per year in its 58 years of service. This may come as a surprise to many. Prima facie, the MiG-21 has been lost at the rate of 4.67 aircraft a year for 58 years, while the Ouragan was lost at the rate of 2.71 aircraft per year for 14 years. Simply multiplying these numbers for the respective aircraft will give you the numbers lost in peacetime accidents in the service life of each type. Clearly the MiG-21 comes out as one of the safest aircraft in the IAF inventory. Only IAF pilots must know how many hundreds of sorties the MiG-21 has taken them up and brought them back safely. No wonder they love it. The MiG-23, Mystere and Sukhoi trail behind the Ouragan. A pleasant surprise is the HF-24 sitting right next to the MiG-21 as an aircraft whose peacetime attrition was lower than all the others.

IAF Su-7 Aircraft. Image Source: IAF

The HF-24 was twin engined, and I did a brief analysis of the combined attrition of twin engined aircraft versus single engined ones. I will not go into details as the twin engines are still in service and do not want to create speculation. Suffice it to say that two engines does not reduce the rate of accidents by half. This is easily explained. As mentioned above there are many causes of peacetime accidents and the loss of an engine is not the only reason.

One final comparison I did was to see if the attrition of HAL made aircraft was better or worse than those that were purely imports such as the Mystere, Hunter and Su-7. By this analysis I found that the attrition percentages over the service life of the aircraft  are almost exactly the same whether they were HAL made aircraft or wholly imported.

Author: Dr Shiv Sastry. The Author is a retired surgeon with a long term interest in military aviation. The views expressed are the author’s own.

Header Image Source: sinceindependence.com

Published by Anil Chopra

I am the founder of Air Power Asia and a retired Air Marshal from the Indian Air Force.

3 thoughts on “Analysis of Peacetime Attrition of Historical IAF Aircraft

  1. Its true Mig21 being called flying coffin is a myth.
    Govt forced IAF to use these aircraft beyond their Russian given expiry/life times.

    But even this analysis is bit misleading.
    What matters what will be the attrition rate against number of hours flying in a year (compare in the last 5-10 years).
    What matters are they currently reliable ?

    Liked by 2 people

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