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September 2011, Archive Story

 

DECEMBER  2011
AN UNPLANNED OVERNIGHT STOP

I spent 7 years on 11 Sqn Lightning’s from 1979 – 1986, both in the Hangar and on the Line.  I regard this first period of my career in the Royal Air Force as still my best tour in over 33 years of service accrued so far that has included 4 years on the Battle of Britain Memorial Flight and travelling the globe with the VC10.  This particular story is one of quite a few that I can relate about my time on Lightning’s at Binbrook – two T-Bird trips in the space of 24 hours is enough to create an indelible imprint in anyone’s memory!

So, to set the scene: it was a mid Thursday afternoon in late summer and a young Corporal Sampson was tinkering with his car outside 11 Sqn’s hangar.  I was due to be in at 1630 on the last night-shift of the week and this was a good opportunity to do some minor work on my car before getting ready for shift later on.  As I was about to depart back to the Block, the sumpy Chf Tech on days, Chf Tech Colin Hillaby, came rushing out of the hangar and accosted me in the car park.  “Phil, what are you doing?” were his first words to greet me.  “I’m just about to go back to the Block and get ready for Night’s, Chief”, was my reply.  “No you’re not” was his deadpan response, “you’re off to Leuchars in 30 minutes to see if you can recover a jet that won’t start.  There’s a T-Bird waiting for you now on 5 Sqn’s Line”.

To give some background to this story, 11 Sqn’s aircrew were carrying out a land away and aircrew turn-round servicing exercise at RAF Leuchars.  Fg Officer Andy Wyatt had landed at Leuchars, carried out his turn-round servicing but the aircraft (a Mk 6) had steadfastly refused to start for the return trip - Andy was effectively stranded at Leuchars until engineering assistance could be sought.  To clarify what I mean by refusing to start, it was the starter motors themselves that had refused to get going, not the actual engines.  At this point of the story, perhaps a brief description of the Lightning starting system would be helpful (from my fading memory) to those of you who are unfamiliar with this aspect of the aircraft.

The Lightning used a highly volatile fuel called Avpin which was stored in a small tank on the spine of the aircraft.  Avpin was supplied under high pressure to the starter motor that was attached to the front of each engine and then ignited; the resultant explosive gasses then driving a turbine that in turn, through reduction gearing, spun the engine up to about 20% rotational speed to allow it to become self-sustaining with coaxing from the pilot.  As the engine lit, rotational forces took over and the starter engagement cog was disengaged to prevent the starter from self-destructing – if I remember rightly, the starter turbine rotated at something like 100,000 rpm.  Starter motor turbine blades deciding to let go and exit through the starter motor exhaust with Linies dodging red-hot scraps of flying metal were not an uncommon sight on the line!  The system itself was relatively straight forward with the majority of its components housed on the spine of the aircraft and thus easily accessible.  To get to the starter motors themselves, however, meant a trip down the intake and cramped, hot and very claustrophobic working conditions, especially if it was the top engine starter motor (No 2) that required to be worked on.

So, to try and expedite the recovery of the stranded aircraft as quickly as possible, it was decided to fly a technician (me) up to Leuchars to try and get the jet going again.  After quickly recovering from the initial shock, any worries about what this was all going to be about were quickly overtaken by a lightning (no pun intended) trip to 11 Sqn’s Squippers (Safety Equipment) and being rapidly kitted out in full immersion suit, mae west and all the associated paraphernalia of straps, helmet, boots etc.  I seem to recall that a doctor came over from the Medical Centre to give me a 1 minute check over and a quick look in my ears; that was the extent of my flight medical and I was classed as fit to fly.  A quick trip to the Tool Stores to grab some tools – a spares pack up had already been provided - and before I knew it I was on my way to 5 Sqn’s line to crew in.  It’s worth noting at this point that I had no overnight or any wash kit with me – just the clothes and flying equipment I was wearing plus my wallet and 1250.

The trip up to Leuchars was uneventful (if any Lightning trip can be called uneventful) and took around 25 minutes (I think) from take - off to landing – things were happening so fast since I had first been told that I had lost any real sense of time.  After landing, it was a case of helping to turn around the aircraft that had brought me to Leuchars and then getting me sorted out – Andy’s stranded Mk 6 was thankfully parked right outside Leuchars’ Visiting Aircraft Section.  I could now begin to start thinking about how I was going to tackle the problem and get to work.  The sight of my ride departing a short while later was somewhat disconcerting as I had no idea at this stage just how long it would take to get Andy’s jet going and how I was going to get back home to Binbrook.  However, I pushed all these thoughts to the back of my mind as I set to work.

First thing to check was the Avpin tank itself – was there enough Avpin in?  By this time dusk was approaching so a check of the level in the tank was carried out with the aid of a torch – all appeared to be in order with the Avpin showing through the filter mesh which was our SOP to check Avpin levels.  After that, I then carried out more checks to ascertain that the ignition system was doing what it should be up to the point of actually pressing the starter button.  To eliminate other potential faulty components, I then spent the next couple of hours down the aircraft intake and changed the starter motor igniters on both starter motors and ensured that there were no flakes of burnt carbon blocking the drainage holes in the starter motor.  It was not unknown for Avpin to pool in the combustion chamber after a failed start if the drainage holes were blocked; any subsequent attempt to start could then potentially ignite the pooled Avpin and physically blow off the starter motor from the engine, wedging it between the intake and the radar bullet!  By this time it was very late, I was tired, grubby and extremely hungry.  So, I managed to get some food from the VHAS guys and crash out in their locker room on an old cot-bed – further work could wait until the morning.

Morning duly came and after scrounging some breakfast from the VAHS guys it was an unkempt and grubby Corporal Sampson who went back to the jet.  I had done pretty much all that I could so it was time to try a start.  However, on checking the Avpin tank again in the cold light of day, the problem became all too apparent; large globules of water were floating on the surface of the Avpin – water and Avpin don’t mix!  I then carried out further checks on the stocks of Avpin that Leuchars was using to replenish our jets with and with the exception of one small can, all the Avpin was contaminated with water.  I was convinced that this was the reason why the starters had failed to operate, so then went about draining and flushing the system with the remaining uncontaminated Avpin that was available.  Being a Friday, the landaway exercise had finished so no more Lightning’s were planned to fly in – this allowed me to use all the remaining uncontaminated Avpin to finish off the job and try for a start. 

After a thorough walk-round of the aircraft, 100% check of tools and equipment to ensure nothing was missing, I grabbed one of the Leuchars VAHS guys to act as Safety Man with a fire extinguisher and then connected a Houchin ground power unit and climbed in the cockpit; the aircraft was full of fuel from being serviced.  After going through all the necessary engine pre-start checks (I can still recall the engine start sequence: battery master ‘on’; engine master ‘on’; instrument master ‘on’; dc pumps ‘on’ and the associated light ‘out’; LP cock ‘on’; throttle set to ‘idle’; starter isolate ‘on’) - it was then with baited breadth that I gave the signal to start the No 1 engine and pressed and held in the starter button for 2 seconds before releasing it.

The fuel/air motor gave out its usual high pitched whine that was followed by the welcome sound of burnt Avpin gasses blasting out of the starter motor exhaust.  After catching the engine and accelerating up to ground idle, checking that all pressures and temperatures were within limits and working as advertised, I let the engine stable for a couple of minutes while I went through the same pre-start process for the No 2 engine.  Another sigh of relief as the No 2 starter motor burst into life and the engine wound up to ground idle and stabilised.  So, with both engines now happily rumbling behind me, I was faced with a dilemma.  If I shut the engines down, there may not be enough good Avpin left in the tank to get the engines going again – there certainly wasn’t any uncontaminated Avpin in the can!  At this stage it was clear enough what needed to happen, and I motioned the VAHS safety man to come up to the cockpit.  Could he get VAHS to get hold of Andy Wyatt, the pilot, and get him to the aircraft ASAP?

I sat in the cockpit and gently exercised the engines while I waited for an answer.  I’m not sure how long it took but Andy duly arrived – he had obviously filed or sorted his flight plan back to Binbrook earlier.  With engines running, I jumped out of the cockpit and he jumped in!  After duly strapping him in, followed by a comprehensive walk round of the jet to ensure nothing was amiss, I waved Andy goodbye as he taxied away from the line - he was soon a blur of green and huge noise as he thundered down the runway, got airborne and headed back home to Binbrook.  By this time it was just past midday on a Friday afternoon, and I had no idea how I was going to get back home.

After breathing a sigh of relief and having placed all my tools, paperwork, spares etc in a small pile, I rang back to base to let them know that the jet was on its way back.  I was then informed that plans were afoot to try and get the T-Bird back up to Leuchars later on that afternoon to pick me up!  With hopes raised of getting back much sooner than any potential train trip would, I spent the next couple of hours in anticipation of another hopeful trip in the T5.  To my great relief, I heard and then saw the unmistakable outline of a Lightning in the circuit!  On landing and taxiing in, who should be at the controls but Fg Off Andy Wyatt, who I had only seen off a few short hours before!  Whether or not he had volunteered to come back up again to pick me up or was told to do so, I do not know – either way, my ride back was here!

The trip back home was superb and included a high speed dash - Mach 1.5 I think – over the North Sea before finally being the last aircraft to land at Binbrook that Friday afternoon.  All in all, a very demanding but superb 24 hours!

By Phil Sampson, Engine Technician 11 Sqn, 1979 – 1986

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