• Thanks for stopping by. Logging in to a registered account will remove all generic ads. Please reach out with any questions or concerns.

Sir Humphrey: "Having Trouble Keeping It Up? The RAF and Typhoon availability"


Fallen Comrade
Fallen Comrade
Reaction score
Start of a post at Thin Pinstriped Line, and an RCAF rererence at end of quote:

According to media reporting of an FOI release about Typhoon availability, the RAF is apparently an air force unable to ‘keep it up’, as their glorious fighter pilot jocks and the boffins below prove seemingly unable to keep these aircraft in the skies. What would Lord Flasheart say?

In other words, the MOD has recently responded to an FOI request confirming that of the 156 Typhoons currently in service, at least 55 of them are in what is known as the ‘sustainment fleet’ and not available for immediate duty. This has been the cause of angry articles in the papers, suggesting that the RAF has apparently ‘failed’.

Lets stop, pause and reflect on what this news actually means. Firstly, it is important to realise that no air force anywhere in the world, at any point in history, has managed to achieve anything like 100% availability of aircraft. All of them work to a similar rhythm of maintenance regimes to ensure a constant flow of available aircraft, which can be surged in a crisis.

Airframes are very complex pieces of machinery that require regular inspection, maintenance and updates to ensure they remain fit and safe to fly properly. In peacetime this necessitates a regular rhythm of deep inspections, planned maintenance and other work to ensure that the airframe is fit and safe for use.

When the decision is taken to buy an aircraft fleet, part of the process of working out how many aircraft are needed involves scrutinising the likely maintenance requirements, projected attrition rates and life of the airframe, and setting this against the jobs that the RAF want the aircraft to carry out.

For example, the Typhoon fleet is currently required to provide a certain number of squadrons, and a certain number of aircraft to carry out ‘Quick Reaction Alert’ on an ongoing 24/7/365 basis, and provide other aircraft to be ready to carry out strike roles such as dropping bombs or launching Storm Shadow.

This in turn provides a clear guide to the RAF to work out how many airframes it needs at any one time to do this. For a purely hypothetical example, to be certain that there are always 2 x 2 QRA aircraft available, planners may require there to be 12 aircraft on a squadron to allow for minor maintenance, training flights and so on. In practical terms this means that you will always need more aircraft available than there are ready to fight immediately.

The RAF uses a concept with its aircraft of essentially having a ‘forward fleet’ of those planes ready to deploy now, or those under light maintenance but able to be deployed quickly if needed. It then has a ‘sustainment fleet’ which is essentially the part of the force which is either undergoing very long-term maintenance, or which is in storage and not actively flying. An example of the figures involved can be found from May 2018 in an answer to a Parliamentary Question about how many airframes were available at any one time.

The reason to put what is a seemingly brand-new airframe in storage is about rotating the hours of the force around to ensure that you continue to keep airframes available for the long term. Jets have a finite life expectancy of flying hours (which can be extended or changed with updates), and over the long-term planners must ensure that they can continue to deliver a credible capability. For example the Typhoon was originally designed for a 6000 hour life, but even 10 years ago plans were afoot to extend this, while the F16 could, in theory, be extended out to 12000 hours

This may sound obvious, but much like a car needs a 5000 /20000 mile service, so too do jets need servicing as they hit hours flown. If you have an entire force of jets flying at the same time, all accruing roughly the same number of flying hours, then they will all require servicing at the same time, and also run out of life at the same time.  The problem if you do this is what do you rely on to get the capability continued? The US Air Force has had this exact problem, where overcommitting on operations and high pressure has left them having to draw on forces from the ‘Boneyard’ as a stopgap to make ends meet [emphasis added].

...The Royal Canadian Air Force reportedly requires 24 hours of maintenance for every hour its force of F18s fly – highlighting the heavy maintenance impact older aircraft can create...