Impact case study database

The “research conducted as a partnership between the Centre of Human & Applied Physiological Sciences at King’s College London and the Royal Air Force Centre of Aviation Medicine has had direct, significant and lasting impact on military aircrew worldwide” [A].

Prior to this research and despite the acknowledgement that G protection is an important component of fast-jet pilot safety, it needed a significant and tragic event to give the issue more prominence. This was, sadly, provided by the Bournemouth Red Arrows crash of XX-179 in 2011, when one of the RAF’s most experienced high-G pilots from their world-renowned display team was overcome by the effects of G and fatally crashed his aircraft. The subsequent Service Inquiry highlighted concerns around the physical state of the pilot at the time of the incident and how this might have contributed to his susceptibility to G. The fatal crash occurred at the end of a flight and one concern raised was whether physical fatigue may have played a contributing part. At the time, there was conflicting information in the scientific literature around whether physical conditioning may enhance, or worsen, an individual’s G-tolerance. Therefore, there was uncertainty about whether someone should undertake physical training and, if so, what type of training they should undertake to address this concern. The Service Inquiry also raised numerous questions around the cultural and organisational approach to the effects of G and precipitated a root-and-branch change to how it was considered and prioritised. Our research in response to this has “changed UK Defence aviation medicine policy, such that the ACP is now a mandated component of the aircrew training pipeline” [A].

Tackling G-LOC and reducing neck injury in the RAF – creating a new training programme

To begin to tackle these problems, King’s researchers were called upon by the RAF to facilitate a repeat of the G-LOC survey outlined above [1]. This second survey demonstrated important new information to the RAF, showing that G-LOC was occurring in pilots during elementary flying training (EFT) (i.e. before they are selected for fast-jet training) and, critically, before they receive any G training [B]. The G-LOC survey was, therefore, a key piece of evidence in convincing the RAF that another layer of G training needed to be introduced early in EFT to address this previously unrecognised risk. The G-LOC survey also served as an important piece of evidence in the justification for significant investment (~£44 million) in a new human-carrying centrifuge [C] which was opened at RAF Cranwell in 2018. The RAF Centre of Aviation Medicine (RAF CAM) have said that “the weight of evidence supported both a new national capability for high G training and a requirement for a bespoke and evidence-based physical conditioning programme” [A].

In addition, the research programme around the Aircrew Conditioning Programme (ACP) [1,4,5] was not only formulated to address research gaps, but to address the issue of the significant morbidity associated with musculoskeletal injury in fast-jet aircrew populations, and in particular neck injury. As such, an important part of the ACP is to provide a conditioning programme that incorporated targeted approaches to tackling musculoskeletal injury. RAF CAM report that the ACP “delivered immediate gain through the management of fatigue when under G” [A].

As described above one of the main findings of our research was the high incidence of G-LOC in aircrew during the very early phases of flight training. The relevance of this finding and its implications have gained greater prominence due to the introduction of a new higher performance EFT aircraft. During EFT, pilots previously would fly the Grob Tutor. However, during the period of our research, the RAF transitioned to using the Grob Prefect as their primary training aircraft. The Grob Prefect can sustain significantly higher levels of G and does not include an anti-G protection system. The RAF recognised that there was now going to be an even greater risk of G-LOC with the use of this new aircraft during EFT, magnifying the findings of our G-LOC survey and reinforcing the importance of the introduction of centrifuge training for EFT pilots.

Prior to the research described above, a structured conditioning programme did not exist for any aircrew within the RAF. Despite increasing awareness of aircrew around the importance of physical conditioning in preventing G-LOC, as evidenced in the G-LOC survey [1], participation in regular physical conditioning by aircrew remained low, which the ACP and our research helped to address.

With its strong empirical underpinning and validity, the ACP was introduced as policy by the RAF in 2017 as an integral component of aircrew training (~40 trainee fast-jet aircrew per year) [A]. This is helping to transform the training and awareness associated with the issues surrounding high G forces for fast-jet pilots [A].

All aircrew at each stage of their training now have to meet minimum standards to progress to the next stage of flight training, with centrifuge training and the AGSM being a key component for fast-jet pilots [B,D]. After the ACP became mandatory for fast-jet pilots “the feedback was rapid and positive: the programme was so welcomed by fast-jet aircrew that it was now extended to crews of other manned platforms” [A]. This is supported by reports of fast-jet aircrew having an improved ability to cope with air combat manoeuvring and less neck pain during training due to their participation in the ACP [D]. The physical benefit it has also impacts protective clothing, with anecdotal reports that many aircrew are now having to have their anti-G trousers re-fitted due to the increases in muscle mass as a result of the ACP. Indeed, some are having to have specially tailored trousers as they no longer fit within the 1970s-based anthropometric size role of the skeletal anti-G trousers used in some aircraft.

The Aircrew Conditioning Programme in action – changing national practice

The effectiveness of the ACP for musculoskeletal injury prevention has also been more widely recognised and is now delivered not only to fast-jet pilots, but all aircrew within flying training, regardless of aircraft type. There are currently ~2500 aircrew in the UK military across all aircraft types who will now benefit from ACP throughout their careers.

Since the adoption of the ACP as standard practice by the RAF, other services have also identified the importance of rolling out this kind of training. The ACP has been further developed for different aircrew populations. For example, it has been modified for helicopter aircrew to address different activities that occur in rotary wing, compared to fast-jet, aircrew. This has resulted in the ACP being adopted by the UK Joint Helicopter Command for all Army rotary wing assets and all Royal Navy aviators [A]. In addition, helicopter aircrew have reported less fatigue and pain associated with flying while wearing night-vision goggles, due to the ACP [D]. The ACP is also of particular relevance to the Royal Navy and the success of their new F35B Lightning fast-jet aircraft (costing ~GBP138,000,000 each) now in service on the UK’s two new aircraft carriers - HMS Queen Elizabeth and HMS Prince of Wales.

The ACP has thus become a UK tri-service (RAF, Army and Royal Navy) conditioning programme. This has, in part, been with the aim of reducing the operational and financial burdens on the Ministry of Defence associated with the high prevalence of musculoskeletal injuries in aircrew, while also reducing the serious risk of G-LOC in fast-jet aircrew, and “has a vital role in supporting sovereign capability” [A]. In growing recognition of the ongoing problems with neck pain in aircrew, the NATO HFM-252 Research Task Group on Aircrew Neck Pain was set up in 2014. This was with a remit to identify solutions, develop a report and produce recommendations to reduce aircrew neck pain [E] with its findings disseminated internationally [F]. The ACP was presented to this working group and “is one of the top solutions recommended” [H] as a strategy that should be employed to reduce the risk of neck pain in aircrew [E,F].

Having been designed and tested by physiotherapists and physiologists, the ACP is now delivered through the Physical Education branches of the RAF, Royal Navy and Army and by those who have undergone training in the delivery of the ACP and completed the ACP Instructors Course Competence [D]. This represents a significant investment of resource, especially from the RAF in training physical instructors to deliver the programme, and in terms of aircrew physical training time to undertake the programme. For aircrew, this is both in training and on frontline operational squadrons where they now have protected time in their working week dedicated to following the ACP. This sends important, visible messages about the importance and prioritisation of G and prevention of musculoskeletal injuries in the Military.

In addition to aircrew, the ACP has wider impact in that it is promoted to all RAF personnel through The RAF Total Safety Magazine: AirClues [G]. This has allowed the entirety of the RAF and any civilians who subscribe to the magazine (rather than just the aircrew going through training) to gain an understanding of the importance of the ACP and why it is an essential part of aircrew training and serves to reinforce the needed cultural change.

The Aircrew Conditioning Programme Beyond the UK

In part due to the ACP contributions to the NATO working group and the development of their report, the ACP now has global reach where “its success and value was further evidenced by adoption by other international Armed Forces” [A]. The Naval Air Warfare Center Aircraft Division of the US Navy have stated that the ACP “remains the most validated and data-supported physical conditioning program which has demonstrated effectiveness in military aviators” [H]. After gaining permission from the RAF, the Finnish Air Force, Belgian Armed Forces and Royal Norwegian Air Force have now also begun using the ACP as a standard training programme for their aircrew. Furthermore, the Royal Canadian Air Force [I] and the US Navy [H] are currently evaluating and tailoring the ACP to become standard practice for their aircrew. The Canadian Air Division have said: “the research has influenced the majority of aircrew conditioning programs in existence around the world today and will continue to be the standard to which all other programs are held going forward” [I]. Whilst the “successful implementation of the ACP within the RAF and its roll out to the Royal Navy and Army and the associated publications have proved invaluable in the justification to progress with an ACP pilot study conducted in US Naval aviation and were crucial in garnering senior leader support” [H]. This greatly increases the potential impact of this work by orders of magnitude; the US Navy alone, for example, has almost 10 times the number of fast-jets (1030 in 2017) compared with the RAF (119 in 2019). As noted by the Canadian Air Division “the significance of this work to the scientific and operational communities around the world cannot be understated” [I].

With high-performance training aircraft (such as the Prefect or Hawk T2) and technically more advanced frontline fast-jets (such as the Typhoon, or the more recently introduced F35B-Lightning), aircrew will continue to be exposed to even higher and sustained levels of Gz. Thus, the threat of long-term injury and G-LOC will remain high to the end of Service life of those aircraft, which is currently in the 2040-50 timeframe. In addition, the UK Team Tempest project is currently addressing plans for a 6^th Generation high-G fast-jet to enter service in 2035-2040. As such, “this maintains an essential and enduring requirement for the results of this research over many decades to come” [A].