Military Aviation – Royal Air Force Puma Retirement (Part 3) – Flying the Puma in the 1980s

The RAF in the 1980s was a large and diverse force, primarily tasked with preparing for a potential war with the Soviet Union, but also dealing with domestic problems with the Troubles in Northern Ireland being a long running and bloody conflict. Friend of the site, Ron Gridd*, was a Puma pilot in that era, having previously served on the Westland Wessex. Here he gives us a glimpse into the joys and challenges of the Puma Force in the 1980s.

I joined 33 Sqn RAF in the mid 80s having completed the operational conversion course at RAF Odiham. Previously I had flown the Westland Wessex on an operational tour in Northern Ireland supporting anti-terrorist efforts there.

The Puma was a leap in technology compared to the Wessex which made it an excellent ‘Support Helicopter’. It was fast, powerful, very capable and exceptionally versatile. It was simple to operate in the field environment and didn’t require excessive maintenance support. It had (for its pre-GPS day when I flew it) some effective navigational kit which certainly trumped that which was fitted to the Wessex (i.e. a map, a clock and compass). It could lift 50% more fully equipped troops than the Wessex plus all their equipment. It could lift an underslung load of over 2 tonnes and had superior range. This could be greatly extended when required by the the fitment of up to four internal ferry tanks which much simplified the organisation of overseas deployments.

Gaining entry to the cockpit of a Puma was a much more dignified affair than the challenge of scaling the outside of Wessex fuselage whilst risking burning one’s arse on one of the two 2ft diameter exhaust pipes! During my time on the Puma it was fitted out for operations using Night Vision Goggles (NVG) which was a revolutionary improvement in night time operations. Blasting around Salisbury Plain at 150ft in complete darkness was an arse-puckering experience of the first magnitude.

Starting a Puma was delightful simplicity after the Wessex – Master Switch ‘on’, Fuel Pumps ‘on’ and then toggle the two ‘start’ switches would get you going. This compared very favourably with the complicated process on the Wessex which involved starting the two RR Gnome engines by manipulating HP and LP cocks – then combining the engine outputs and engaging the main drive system to get the rotors going, using an array of levers better suited to the bridge of a ship. Get this process wrong and one could easily destroy the coupling gearbox. There were no automatic safeguards or protections. This is why, when converting on to the Wessex, the first ‘trip’ involved merely starting up and shutting down the beast – this took about an hour for the uninitiated and required strict adherence to the Flight Reference Cards which were of ‘phonebook’ proportions.  With constant practice, one improved!

So, the mighty ‘Plastic Pursuit Ship’ (the blades were made of a then innovative composite material as opposed to an alloy skin surrounding a central spar and honeycombe filling I had previously experienced) was an exciting new partner which could easily seduce an unsuspecting converting pilot into thinking she was without vices.  Alas that was definitely not the case.

The Puma – alias the ‘Stumbly’ – did not earn that nickname by accident – or rather it did – several of them! Although engine start was simple, other traps lay ahead. Releasing the rotor brake in a timely and controlled manner was essential in order to get the main rotor blades rebalanced quickly on start up. The main rotor mast was inclined forwards at 7 degrees from the vertical which was good for efficient cruising when airborne, but when shut down the effect of gravity would cause the rotor blades to extend their drag dampers to maximum extent thereby producing a very marked eccentric imbalance as each of the four blades had a mass of several hundred kilograms.

Thus, when the blades started to slowly accelerate, there was normally a most obvious and alarming wobble which would continue until idle RPM was achieved. This was exacerbated by a relatively narrow track undercarriage and the essential Gallic design of the Puma which put all the heavy bits like the engines and gearbox on the roof. Imagine strapping a small elephant to the roof rack of your family car, then seeing how it handles on sharp corners.

Vertical takeoff to the hover was the easy option. If, however, one was operating from traditional airfields where taxiing was required, the castoring but unsteerable nose gear had a habit of getting itself stuck at 90 degrees to the direction of travel. An inexperienced Puma driver might then instinctively apply more and more forward thrust to rectify the situation in order to straighten the nose wheels  – alas this is where the Puma would fight back with a sudden and uncommanded yaw, followed by an opposite roll, a pirouette around a single main wheel and a final death roll to one side whereby the main rotor blades would contact the ground, their ever-shortening stumps gaining traction into the concrete like a dog with worms dragging its arse across a carpet. Although seldom fatal (Puma not dog), the resultant heap of horizontal smoking wreckage was not an uncommon sight in the early days and was actively discouraged.  

Once finally airborne, things generally started to improve. The ability to put an increasing mileage between yourself and your operating authority could only be viewed positively. Transits to the various UK military training areas such as Otterburn, Salisbury Plain, Sennybridge in Wales and Stanford in East Anglia (amongst many others) was generally achieved at low altitude (about 100ft) for ‘training’ purposes which precluded effective radio communication with the same aforementioned operating authority. In those days a Puma crew comprised a single pilot and a single crewman. The latter were worth their weight in gold and were definitely multi-purpose.

A good crewman would copy the pilot’s proposed route onto his map to assist navigation when required, manage all aspects of the load whether it might be human, canine, internal, external, perishable, explosive or anything else. They would assist with lookout, giving a continuous verbal commentary to the pilot to complete his situational awareness, especially when carrying external underslung loads. On field exercises, my favourite attribute of a top crewman was one who could get a brew on within seconds of shutting down in some dark wooded corner of Europe.

So, having arrived in the vicinity of one’s tactical operating area at a vast (for a helicopter) rate of knots (about 140!), it was then the pilot’s responsibility to decelerate as fast as possible and land so the crewman could get his portable kettle going. This involved a lot of extreme nose up attitude and very low power settings as the windmilling rotor disc was driven by the passing airflow. This was, of course, normally attempted at very low altitude (25ft or so) and particular focus was concentrated on the lowest part of the helicopter which was most likely to impact terra firma first – in this case the tail.

A sensible helicopter designer might have thought to helpfully install a wheel in this position in order to facilitate a swift tactical arrival. Not so Monsieur Aerospatiale, who instead installed a rudimentary metal stick in this position. Thus a sensible pilot focussed a disproportionate amount of attention on keeping his backside out of the surrounding countryside. This was a contentious issue amongst ex-Wessex pilots who had previously enjoyed Mr Sikorsky’s idea to install a thumping great tail wheel at the back which seemed to be designed to tolerate no end of clumsy handling abuse.

If this was not enough of an Achilles heel, the engine handling characteristics of the Puma were impressively deficient. As mentioned, the rapidly decelerating helicopter would need virtually no power as it arrived at a high nose up attitude. Things then change rapidly as the helicopter comes to an abrupt halt and enters the hover. In the hover, a helicopter is at its least efficient phase of flight – so within a second or two the required engine power goes from zero to maximum. Those familiar with the natural characteristics of the gas turbine will appreciate that they definitely do not like to deliver power in that manner. Instead, if the engine RPM is allowed to become too low in such circumstances then it will steadfastly refuse to accelerate when demanded. The resultant lack of power and therefore loss of rotor RPM and therefore lift and therefore (very) heavy landing and therefore court marshal concentrated that part of the pilot’s brain that wasn’t already dedicated to assessing the distance between the tail skid and (typically) Wiltshire.

The wary Puma pilot would have both eyes firmly glued to the critical engine RPM above which all was well but below which there was guaranteed trouble. There was of course an elegant solution to this problem – an electronic gizmo that anticipated the forthcoming power requirement and injected a bucket load of fuel into the combustion chambers before the engine knew it was needed. Such devices were installed on other helicopters – yes, the old fashioned Wessex – and they worked beautifully. 

These unfavourable characteristics are endemic in most gas turbines, but were particularly severe in the engine installed in the Puma which was originally reputedly designed to power trains and for drying out stockpiles of grain.  In defence of the design it was also an incredibly robust power plant which could easily cope with ingested birds before the later air intakes were installed on the fleet.  

These engine handling issues remained unaddressed for many years and were only resolved when the Puma Mk 2 was introduced into service about 30 years after I left the Support Helicopter force. Sadly such demanding handling characteristics were determined to have detrimentally contributed to at least one fatal accident when the Puma was deployed in very harsh combat environments. 

My personal experience on the Puma saw me operating in environments from frozen Norway to tropical Belize and many points in between. I remember a particularly demanding nighttime extraction of  a severely wounded casualty from a jungle clearing many miles from medical help which was way beyond what was expected and what was normally permitted – not to mention my personal experience. After delivering the casualty to a local army field hospital, I was just smugly congratulating myself on his rescue when a doctor hurried into the room (a jungle hut really) and told me that the unfortunate patient was at death’s door and would not survive unless he was evacuated 250 miles north to the biggest hospital in the country.

This was not an edifying proposition as it was now pitch black outside, the darkness occasionally punctured by the flashes of lightning from a low overcast sky and rain of biblical proportions. There was no way that an IFR transit could be attempted in such atrocious weather so we tried to creep our way north at an extremely uncomfortable altitude in very variable sharply undulating terrain. After about ten minutes, the water ingress to the front of the Puma was such that the intercom failed, together with all our radio equipment. There was no way to communicate with each other than by chinagraph pencil on a kneeboard. I recall that evening of forty years ago with uncomfortable clarity.

Other highlights of my time in the company of Percy Puma include delivering ‘specialists’ onto the deck of ship via short tactical ropes at night. Similar specialists were delivered by the same means onto the roof of a moving train – very James Bond – again at night. Various technical fits to the aircraft enabled  exceptionally interesting deployments where we assisted the local security forces by providing photographic and video images of subjects of interest. 

An urgent deployment to Scandinavia to deliver a replacement engine to an unserviceable squadron colleague was hampered by extensive bad weather on our planned route through Belgium, Holland and Denmark. A hasty re-plan took us up to sunny Aberdeen then out into the North Sea where our range was a bit too uncomfortable to make it in one go, so we refuelled en-route at the enormous Brae Alpha oil platform. My precautionary visit to the briefing facility at the resident North Sea helicopter operations room yielded that the platform was easily located by its NDB beacon but if that didn’t work it showed up well ‘on your weather radar’. I was too embarrassed to admit that we had neither installed on our aircraft. Somehow we found the rig by traditional methods and a very professional rotors-running refuel was gratefully received. Engine successfully delivered we returned via night stop in Amsterdam which was also of interest.

Operations in Northern Ireland were always interesting – from helping to construct the now defunct observation towers by lifting dozens of 2 tonne steel armoured plates into position, to reconnoitring proposed routes for troop movements using specialist equipment to ensure there was no associated terrorist activity. Overt and covert observation missions were commonplace and often both hugely demanding and rewarding. On one occasion we arrived in the dead of night unannounced at a police station landing site having escaped the clutches of a winter snow storm under a very large CB cloud. It was 15 minutes before the wind speed had abated sufficiently to enable engine and rotor shutdown (helicopters have a track record of eating themselves if shutdown is attempted in limiting wind speeds). When we finally did so, inspection revealed a thick coating of ice on much of the fuselage. We were lucky that night. 

More enjoyable escapades were to be had in warmer climes. A regular task in Belize involved re-supplying an army observation post on a tiny coral island many miles off shore. The island was so tiny that the only flat landing area was right on the beautiful coral beach and left the tail of the Puma overhanging the azure Caribbean Sea. While our passengers completed their administrative tasks, it was impossible to resist the temptation of a fantastically refreshing dip in the ocean – happy days indeed.

Another fun deployment was to the gunnery ranges at Otterburn in Northumberland. On this occasion, we were being used to move targets which comprised abandoned vehicles and aircraft to various new locations as underslung loads. The targets would then be attacked by aircraft on a NATO exercise. The range became active at 12 noon sharp by which time we very definitely had to be out of the range area. The task lasted about 4 days and the only available local accommodation was in a very comfortable local pub, conveniently located underneath the active range airspace. Once we were shut down there after 12 noon, there was no way that we could legally takeoff until the following morning. This proved to be enormously convenient as Jim, the landlord, had a comprehensive selection of draught beers for us to sample. We obviously weren’t  the first crew to enjoy Jims’s ample hospitality as he even had a set of chocks made to fit a Puma.

A little bit of diplomacy was required on one occasion when whilst conducting an ‘enthusiastic’ approach to the pub car park we saw, at a very late and unavoidable stage, three elderly ladies enjoying a picnic on a park bench. Having overflown their chosen spot at a frankly insultingly low altitude my crewman described in awful graphic detail the ensuing carnage as the ladies smart red check gingham tablecloth was overwhelmed by our wake turbulence, folded itself into an untidy ball then flew off about 25 metres, disgorging various pieces of picnic as it went. Expecting imminent letters of complaint to my commanding officer I set forth on a hearts and minds campaign to appease the offended ladies. Far from being angry, they said that they were only there to ‘observe the helicopter’ and were delighted to have been blown away by the very same. Three dry sherries later all was well in the world.

My time on the Puma was hugely rewarding. Literally never a dull moment and one never knew where the day would take you. We were the front line for unexpected events. Delivering VVIPs from LHR to Westminster at 5am one day and surveying Greenham Common as a potential Space Shuttle emergency landing site the next. Other jobs included those that are still relevant to modern military and policing activities which had better remain as a private memory.  It was a pleasant state of organised chaos on the Puma fleet, but I shall never forget it. 

GAR would like to thank Ron Gridd for such a wonderful account of life on the Puma in the 1980s. Ron is currently enjoying a well earned retirement involving sailing and his garden and we wish him all the best.

*Ron Gridd is a pseudonym.