Inc Idents and airworthiness engineer Malcolm McBride ... · Inc Idents and accIdents 48 JUNE 2015LIGHT AVIATION | SAfety Spot I featured this picture showing the remains of an electrical

W elcome, as always, to this midsummer issue of Safety Spot; thanks for tuning-in, I hope all’s well for you and those around you. Now the weather’s

improved a little, all the various departments here at LAA HQ are working at full power just to keep pace with the incoming work which, apart from the problem of finding time for a bit of personal space, is just how I like it.

So far, as you probably know, this year’s weather has been rather dominated by the southerly course of the jet stream and, at least here in the south of England, the weather’s been very changeable… I’ve hardly had the sails up on my old yacht, Vita Nova, this year as the wind’s either been too strong or, you guessed it, not registering at all on the anemometer. I’m writing this issue of Safety Spot over the May bank holiday weekend, which is a bit annoying as I had originally

planned to sail off for a few days; just for a change, there’s a steady 15kt south-westerly blowing in the Solent (thanks to Bramblemet!), just right for a trip over to Cowes… but then, when you’ve gotta work, you’ve gotta work! In any event, tomorrow’s forecast is rain.

Let’s start with a correction to the article about the Luscombe that suffered an ASI failure on take-off and subsequently ran into an obstacle after the take–off was aborted. You will recall, if you’re a regular reader of Safety Spot that, in the April issue, I used this ASI failure to chat about the importance of maintaining a certain ‘discipline’, especially with regard to ongoing maintenance work, within the group-owned aircraft world. I was impressed, if you recall, by the way that this little group of five managed their affairs; perhaps it would be better if I let the group’s Technical Manager, Duncan Campbell, explain what’s worrying him about the article. His letter starts by reminding me that the

group had been invited to visit the RAF base at Odiham, mostly to discuss the best way of avoiding any incidents with the Chinooks that operate from there.

Thank you for your coverage about our Luscombe, G-AGMI, in Safety Spot in April’s issue of Light Aviation. We all thought it very balanced and well-crafted. We had a successful visit to Odiham and, when the RAF have confirmed the measures we agreed, I’ll forward a brief report and photo(s) as discussed. When we visited, there were very few Chinooks in residence and, as they were deployed to Nepal shortly after, I think we’ll have a little wait before we hear from them.

My purpose in writing now is because the article contained one small error in identifying me as the pilot. I was actually P2, subject to the full experience but not PiC. It naturally caused my sympathetic group colleagues, including the P1, some mirth and I thought

It turns out that we can all make mistakes, whether reporting on previous incidents or making decisions in an emergency

IncIdents and accIdents

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I featured this picture showing the remains of an electrical connector, which started its life being attached to a rear fuselage mounted remote compass in an RV-6, in the May issue of Safety Spot. We were worried that the bits and pieces could jam the elevator controls. The slight suggestion, made in the caption to the photo, that the corrosion protector AC-50 was involved, raised the eyebrows of the boss of the company that makes this magical substance… unzipping plastic’s molecular structure isn’t one of its properties in his view… see the very nice letter in the accompanying text. (Photo: Tim Gibbs)

With Malcolm McBrideairworthiness engineer

“ To date ACF-50’s

chemistry has not been found to degrade or

embrittle any type of aerospace

composite or plastic component”

LA06.safetyspot.v4.IW.indd 50 26/05/2015 15:55

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it not worth raising when the magazine was published. However, I am now running into other flying colleagues who are asking me why I had misled them! Like my group colleagues, I take the view that what happened to my P1 colleague on that occasion could so easily have happened to me, and the outcome may well have been the same, but putting people right is becoming a little tiresome. I wonder if you could possibly acknowledge that the pilot was incorrectly identified in the article in a future issue of the magazine.

Thank you Duncan, I hate to think that an error on my part has caused dissent amongst your mates and am glad to be able to correct the mistake… Honour restored and we’re looking forward to your promised article about your group’s visit to Odiham with regards to the airspace issues around your strip. Having spent some time flying in Nepal, I feel a certain attachment to the people there and watched the TV in horror as the disaster unfolded; well done to the UK Government for acting quickly with some airborne assistance. By coincidence, I heard on the radio yesterday that there had been an earthquake in Kent the previous evening but, apart from knocking over a few bins, the 4.2 (Richter scale) event didn’t cause any injuries… just goes to show you though, you never know where the next problem’s going to come from.

You will also, I hope, remember the picture of a failed electrical connector to the tail mounted AFS magnetometer, sent in by RV-6 owner Tim Gibbs. The picture was featured in last month’s mag. He was mystified why the plastic connector had failed and suggested that the commonly used anti-corrosion spray ACF-50 might have affected the plastic in some unusual way. I featured the picture to remind owners to check things carefully, even if they’re hidden away at the back of the airframe - in other words ‘get the panels off during a maintenance check, especially at an annual. In the failed connector’s case we were especially worried about the debris falling into the elevator control mechanism and causing a jam. Well, Brian Hope, our Editor, sent me an

(Above) Legend has it that Homer Kolb, when he was a lad, reasoned that, “If you could build a silo on a farm as high as 70ft without permission, then that airspace up to that height must belong to the farmer.” That boyish thought set him on his way to building his first ultralight aircraft, the Kolb Flyer which first flew in the early 1970s. Looking at the sports aviation marketplace now, Homer Kolb should surely rank as one of the great innovators of our age. This picture, of a rather more recent example of this, for its day, very advanced ultralight, reminds me a lot of one of the first UK microlights that I got my hands on, Steve Hunt’s Pathfinder (the Mk. 1!); that very early single-seat full three-axis microlight flew like a dream as I remember. I’ve personally never flown a Kolb, but the Twinstar Mk. III, has a bit of a reputation as a rather poor performer and doesn’t enjoy particularly good handling. (Photo: LAA Library)

email he had received from Mark Pearson, the Managing Director of Lear Chemical Research Corp (www.learchem.com) that makes ACF-50 and I thought you might like to read it.

Let me start by saying I think you and your staff do a wonderful job presenting a very ‘reader friendly’, informative magazine that is full of useful bits germane to the LAA readership. While we don’t see them here in Canada, I have had the pleasure of reading several issues during my travels to the UK.

It was recently brought to my attention that the May issue contained a reference to our anti corrosion product ACF-50. This was on page 52 of the article Safety Spot. I would like to address the interesting comment made in regards to ACF-50.

The picture shown is of a shattered plastic D connector with the supposition being made that perhaps the vapour from an ACF-50 treatment reacted with the plastic material, causing it to become brittle and disintegrate. To educate your readership, ACF-50 was first introduced to the aerospace industry in 1985. During this 30-year period ACF-50 has had both direct and indirect contact with all types of aerospace metals, composites and plastics, including those found in some connectors. ACF-50 has been tested to aerospace specifications which specifically evaluate the product’s compatibility with plastic materials. To date ACF-50’s

(Left) Here’s Alex’s sketch of the accident site near Otherton airfield. Alex and a pal had planned to go on a cross-country flight in this Kolb to the Long Mynd but, shortly after take-off, he became aware that the elevator control had jammed. Fortunately, the aircraft was in a reasonably stable flying attitude, although the aircraft was nose down and steadily descending. However hard he tried, he couldn’t get the stick back to pull the nose of his aircraft ‘up’. Alex, thinking very quickly indeed as you will imagine, elected to land as close as possible to straight ahead, using only the throttle, ailerons and rudder to maintain control. (Diagram: Alex Crowley)

chemistry has not been found to degrade or embrittle any type of aerospace composite or plastic component.

Having said that there are a variety of aerospace and automotive grade electrical contact cleaners that if used on ‘non-compatible’ plastic materials will – almost on contact – cause the embrittlement experienced by the RV owner.

We are not sure what caused this connector to shatter but can assure your readership that ACF-50 was not the culprit .

I think that Mark’s letter says it all, certainly I haven’t heard that ACF-50 does anything else but protect materials against corrosion… a job it seems to do very well indeed. Thanks Mark for taking the trouble to write and I’m glad you enjoy Safety Spot.

So, what’s happening in our fleet? Well, I’ve just collated the reportable incidents and accidents for the first trimester, that’s January through April 2015, and we’re just a tiny bit up on the annual average. Last year we recorded 63 incidents so, without trying to be too clever about it, by now we would expect there to be 21 reports - I’ve actually recorded 24. The interesting thing, and the reason for me giving you these numbers, is the huge hump in the graph describing Loss of Control during take-off or landing. I alluded to this being likely at the beginning of the year and urged members

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to take a check-ride if it had been a while since they (you!) had last flown. If you’re not very current you’ll probably get away with a flight if everything goes well and there are no problems. The story is very likely going to be different if you get hit by that gust of wind with your name on it or, as in the case of the two incidents I’m going to discuss later in this issue, you get a technical failure of some kind.

Of the 24 incidents so far recorded, 16 relate to loss of control either on take-off or landing, and two relate to loss of control during an approach, so losing control of the aircraft during the busy section of a flight accounted for 75% of all the incidents. From our 24, only six have significant technical content and four of these incidents relate to accidents after an engine failure, three Rotax two-stokes and one Jabiru 3300… the Jabiru failure occurring, incidentally and sadly, on its first flight. See next month for the very interesting issues connected with this incident.

So, most of our aircraft get broken during take-off or landing. “OK,” I can almost hear you thinking, “Tell me something I don’t know!”

There are two particular incidents with significant technical issues, and some operational points, that are worth exploring.

KOLb T WINSTAR MK. III – IN-FLIGHT ELEvATOr COnTrOL FAILUrEAs I hope that you will recognise, I do try quite hard to create a theme within Safety Spot; this month, two recent accidents are so similar that the tune to be played and, perhaps, the lessons learnt within, are fairly obvious. Both accidents led to the aircraft being written-off but, very happily, neither caused any injury to the occupants. Another important, and rather unusual congruence, is that both the pilot/owners willingly agreed to me chatting generally about the causes even though a different decision by the pilot during a difficult situation may have resulted in a better outcome.

We’ve got 38 Kolb Twinstar aircraft on our books, although at the time of writing we only have 13 aircraft in-Permit and still flying - well, actually 12 aircraft still flying if you remove this particular machine from our list, which I’ll do in a minute! That’s not the best of ratios, although in fairness, the Kolb Twinstar was a microlight aircraft of its time and, whilst it

A possible reason for this control jam was that both the pilot and the passenger flew with their coats unzipped; it’s very possible that the wallet and big bunch of keys may have been of a sufficient weight to alter the position of the drive cable’s turnbuckle (relative to the aircraft’s structure) to cause a temporary jam. (Photo: Malcolm McBride)

When we looked more closely at this point in the elevator control circuit, we could very easily simulate what might have happened in-flight: whilst it was possible to simulate a jam on the ground, even a small movement of the stick ‘tripped’ the temporary ‘lock’ allowing the system to become free again. (Photo: Malcolm McBride)

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Because the pilot didn’t think that he had any pitch control he found himself unable to accurately control the glide path of his machine and, after stalling during the last few moments of the difficult approach, the port undercarriage assembly struck a fence post; effectively destroying it. The aircraft ‘belly-landed’, slewing round to port after touchdown. (Photo: Otherton Crew)

With the hammock-type seat-back removed, this picture shows the fairly complex tubular structure involved in connecting the front of the cabin to the rear fuselage tube. Much of the tubing relating to undercarriage support was bent, but the damage was limited to the undercarriage fixings. note the push/pull elevator drive rod connecting the belcrank to a centre-mounted control stick. (Photo: Malcolm McBride)

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Further evidence to support the theory that the elevator jam was caused by a turnbuckle impinging itself on the edge of the fuselage’s rear tube can be seen in this photograph; note the witness mark on the inside face of the tube. The insulating foam, incidentally, was fitted to try to stop an ‘annoying’ rattle made by the cables in normal flight. (Photo: Malcolm McBride)

This picture shows a close-up of the rod-end bearing used to connect the elevator push/pull rod to the belcrank; aero-engineers will normally always require this sort of critical control joint to be made failsafe (in the event of a bearing failure) by fitting a penny washer under the head of the attaching bolt; with a washer in place the connection will remain functional even if the bearing falls to bits… comments about the quality of the lock-wiring of the turnbuckle were noted by the author when he showed this picture to the Chief Engineer but, it’s artistically creative ‘unconventional’ appearance didn’t mean it wasn’t effective… just rather difficult to recreate! (Photo: Malcolm McBride)

The Kolb Twinstar, as a type, has a checkered safety record and one aspect that is very worrisome is the lack of protection to the pilot in the event of a heavy landing. Following some serious back injuries sustained during accidents in the early 1990s, a Mandatory Permit Directive (MPD) was raised by the UK CAA to require a modification strengthening the seat-pan of all UK Twinstars This picture shows the seating arrangement found on the incident aircraft and, whilst some protection was afforded by the seat cushion, it wasn’t modified in accordance with the MPD. It has to be said that the crew of this aircraft were lucky not to sustain a serious injury in this accident as it did involve an undercarriage failure. (Photo: Alex Crowley)

Mandatory Permit Directives are, in the Permit to Fly world, equivalent to Airworthiness Directives in the Certificate of Airworthiness world; they’re ‘Directives’ and, unlike Service b ulletins or Letters, they contain ‘must do’ things. Until 2011, the CAA published a compendium of all UK MPDs (CAP 661), this document, frozen in 2011, is still available from the CAA’s website (Type: CAA CAP 661 into your search engine) but later MPDs are now only posted online. Either way, if you’re conducting an annual maintenance review on an LAA aircraft (Part of the Permit renewal process), it’s essential that all the required MPDs are signed off in the log-book (and, of course, accomplished on the aircraft!). The above picture shows the MPD relating to the fitment of the seat pan and the drawing of the seat protection scheme that’s needed. (Photo: UK CAA/LAA Library)

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did look quite good, it didn’t have a reputation of being a good performer. I do remember one very experienced test pilot calling me one afternoon here at LAA HQ exclaiming over the telephone, “I can’t sign this off, it’s very slow and doesn’t appear to be handling correctly.”

Worried that there may be something critically wrong with this particular example, I asked an experienced Kolb man to fly the aircraft on test, issuing a special Permit Flight Release Certificate to cover the flight with my personal warning, “For goodness sake be careful.” After a couple of weeks waiting for some appropriate weather the new test pilot emailed me stating that, ‘Yes, its handling is pretty unusual, but very normal for type: and there’s nothing wrong with performance… at least for the type.’ There’s no doubt though, if it’s cheap airtime you’re looking for, it would be difficult to beat this generation of machine for price, but don’t expect Spitfire handling. I must sample one myself sometime.

Anyway, very belatedly, because of all sorts of administrative hiccups, we only found out that there had been a fairly serious incident involving a Kolb Twinstar Mk. III about three weeks after the occurrence. Fortunately, we heard about it just before disposal of the airframe by the rather expeditious insurance company, as the machine had been written-off. I met the owner of the machine, LAA’er Alex Crowley, at Otherton on the day that the pilot and previous owner of the Kolb had just collected his replacement, a fabulous Rans S6 ESA, bought with the settlement.

Alex has about 75 P1 hours under his belt out of a total of about 150 flying hours; originally he trained on a flexwing, only recently converting to three-axis types. In fact, he had only accumulated four hours on the Kolb, all P1, so I don’t think that Alex would mind me saying that he was rather learning ‘on-the-job’ with this new type! I was amused by one of his comments, made whilst Andy Draper and I looked round the machine. I asked how she flew. “Well” Alex replied, “Everything seems to happen at 60 mph!”

I fell in love with the Aero-Designs Pulsar as soon as I saw a picture of the first prototype back in the 1980s… so much so in fact that I went to the States to visit the aircraft’s designer, Mark Brown, and bought a kit after half-an-hour’s flying in his prototype! The original version was powered by the rotax 582 two-stroke engine and, primarily because of the machines very lightweight, handled beautifully. This example shows the later model which was fitted with the 912UL engine. Sadly, for all sorts of reasons, this particular type never really got off the starting blocks here in the UK; the clearing banks withdrawing support from most of the UK’s embryonic sport plane businesses in the early 90’s didn’t help much! (Photo: LAA Library)

“There can be little worse for a pilot

than to suffer a loss of control authority, especially at such a low height; it’s a

situation that, in very real terms, could be described as a life or death moment”

Here’s what happened in Alex’s own words.The intention was to fly out to the Long

Mynd, accompanied by two other aircraft. A full walk-round inspection was carried out prior to entering the cockpit. After start-up I taxied to the hold of Runway 25 (The wind was roughly westerly, at or about five knots) where I performed my pre-take-off checks. Inclusive in the checks was a control check which indicated full and free movement. As there were two ‘POB’, I selected the rearward trim (It is likely that the aircraft was close to the maximum weight allowed which is 390kg) and the first stage of flap for take-off and the ground roll commenced. All instruments were within limits and the airspeed indicator was ‘alive’. The aircraft climbed away at 60mph indicated, as usual. Upon reaching 200ft the flap was retracted and the climb continued. A shallow left turn was initiated at around 450ft to conform to the circuit procedure and remain clear of the M6 motorway.

At this point severe restriction on the control column was felt. The aircraft then began to descend but the elevator control was extremely hard and the descent could not be arrested despite the application of full power. Given the rate of descent I was confident I would not make it back to the field and so I decreased power to decrease the rate of descent and initiated a forced landing. The only field I considered suitable was a small paddock with grazing livestock. Conscious of how short the field was, with little control authority, I aimed at the edge of the field. Upon passing 50ft I made a Mayday call on the local frequency which alerted my fellow pilots. As I came into the field my left wheel struck a wooden post, destroying the wheel and wing strut.

There can be little worse for a pilot than to suffer a loss of control authority, especially at such a low height; it’s a situation that, in very real terms, could be described as a life or death moment. Alex, when confronted with an elevator jam, would have known that he needed to act quickly if he and his passenger were going to survive. I have little doubt that his ‘fight or flight’ response system would have kicked-in and the decision to ‘get back onto the ground quickly’ was made almost in his subconscious. If you’ve read the above part of Alex’s report carefully you may have noticed a couple of questionable actions. The first question might be why Alex reduced power to reduce his rate of descent? Well, as you can see from the attached pictures, there is quite a power related pitching moment on the Kolb because of the position of the engine. This gives an unusual feel to pilots more used to the aircraft nosing up with an application of power; with aircraft like the Kolb, an application of power pushes the nose of the aircraft down. So, Alex was clearly thinking about improving his chances of survival.

The problem with reducing power, especially on a draggy aircraft like this, is that in reality, reducing the nose-down pitch angle won’t necessarily reduce the rate of descent - perhaps, and as it turned out, the opposite


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would be true. An eyewitness reported that the aircraft ‘became quite slow on the approach and stalled just as it was going over the field’s boundary’.

So this pitch ‘issue’ caused a bit of a balancing act which the pilot very nearly got completely away with… as it was, it was a successful emergency landing because both occupants walked away without injury, so very well done to Alex. My critical comment here is that you can’t beat airspeed as a currency in a situation where you’re forced into a field… it’s your cash in the hand. Height, if you’ve got any, can be thought of as ‘money in the bank’, and below 500ft you’re not very solvent unless you have a sensible airspeed!

Another critique is that 50ft on an approach, under any circumstances, is no time for radio calls, even Maydays.

I’ve covered what the most likely explanation for the control restriction was in the accompanying pictures. The aircraft itself looked to be in fair condition but it was clear that it hadn’t been maintained very well through its life; both elevator drive cables were far too slack to be effective, an issue noted previously because somebody had tried to reduce their rattling by covering them with water pipe insulation and this alone probably led, as you can see for yourself, to the temporary jam. Also, at the last annual inspection, neither the previous inspector nor the new owner had taken a look through the aircraft’s Type Acceptance Data Sheet (TADS). Had they have done so they would have noted the mandatory requirement to fit a strengthened seat pan and a special, high density foam seat cushion.

That aside, if you ever get into an awful position where you end up with an in-flight emergency, try to resist the ‘blinkering’ effect caused by the ‘fight or flight’ response; in any situation there will be a number of options. OK, you will inevitably act quickly to save the day but, if you’ve got time, reassess the situation. In this case, if Alex had operated the elevator control a few times or, perhaps, just looked at the control mechanism, he would have realised that the control restriction was only a temporary one; and, perhaps, if the crew had simply just done up their coats, the emergency situation would have passed as just another crew-room story.

PULSAr XP – In-FLIGHT THrOTTLE FAILUrEIn this next example, a similarly experienced chap had another type of control issue and, even though his method of dealing with the emergency was, and I hope he’ll forgive me for saying this, a bit daft, he stuck with his plan to the bitter end.

I received a little note from Fiona, one of our fabulous engineering admin support staff. Eyebrows oscillating hopefully I read, ‘Keith Rigby, the owner of a Pulsar phoned… he wants to report an incident’.

Keith answered his phone after a couple of rings and I said, “Hello Keith, it’s Malcolm. You OK?”

“Not really”, he replied. “I don’t have an aeroplane any more.”

After a bit of a chat I was happy to work out that although the final moments of Keith’s Pulsar were pretty dramatic, he walked away from the crash without a scratch.

Let’s start from the beginning, well perhaps not the very beginning; I’ve only got enough

This picture looks down and aft onto the rotax 912 UL engine as fitted to the Pulsar that suffered an in-flight throttle control failure. notice that the port carburettor air filter is a different shape to the starboard suggesting a considerable movement of the engine during the impact. The important thing to notice is that the modified throttle system includes two very short b owden cables, one to each carburettor. b ecause these cables are very short, any movement of the engine transmitted drive to the throttle cable itself, often asymmetrically, which showed itself (in hindsight) through irregular bouts of rough running.

This is a good example of why it is essential to get a modification checked-out and approved by a qualified organisation. Certainly this new throttle system, featuring left and right throttle levers, is a more conventional system than the one originally approved on initial build (basically a single throttle lever with the cable passing through a one into two splitter box). The new system has the advantage of the variable throttle friction device on the P1 side, necessary with a carburettor designed to default to full power if its control connection is lost. However, the design features a number of gotchas which would have been spotted during an approval procedure. (Photo: Keith Rigby)

The picture on the top shows how the throttle should look when assembled correctly and the one on the bottom shows how it was found by LAA Inspector Alex Hastings, after he visited the aircraft to try to establish for us what had gone wrong with the system to cause it to fail. b ecause the nut securing the throttle lever to the angle bracket attachment wasn’t sufficiently locked in place it had come undone and was rattling up and down the stainless steel shaft behind the instrument panel to which it was affixed… every now and again the nut would jam under the shaft stopping the throttle from closing fully. The silly thing (again, with the benefit of hindsight) is that this ‘jam’ had happened before to the pilot although on previous failures, after a bit of ‘wiggling’, the jam had cleared. He’s kicking himself now of course because he didn’t check this annoying problem out at the time. (Photos: Alex Hastings)


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LAA project Registration Kit Built Aircraft £300Plans Built Aircraft £50Issue of a permit to t est f ly Non-LAA approved design only £40Initial permit issue Up to 450kg £450451-999kg £5501,000kg and above £650permit renewal Up to 450kg £155451-999kg £2001.000kg and above £230Modification application Prototype modification minimum £60Repeat modification minimum £60

t ransfer (from CofA to Permit or CAA Permit to LAA Permit)Up to 450kg £150451-999kg £2501,000kg and above £350f our-seat aircraft Manufacturer’s/agent’s type acceptance fee £2,000Project registration royalty £50Category changeGroup A to microlight £135Microlight to Group A £135Change of G-Registration feeIssue of Permit Documents following G-Reg change £45Replacement DocumentsLost, stolen etc (fee is per document) £20Latest SPARS - No.16 February 2015

LAA engineering chArges – PLeAse nOTe neW fees hAve APPLied since 1 APriL 2015

space for a few hundred more words! Keith, like many of the LAA’s flying membership, came to flying as soon as the realities of his life allowed, in Keith’s case his early 70s. Not that, perhaps like many, he hadn’t maintained a ‘very close interest’ in all matters aviation; it’s just that the opportunity to actually learn to fly didn’t happen until he was, well, 72. Keith started to learn to fly at Cumbernauld Airport in Scotland and, after 60 or so hours training (and practicing), gained his PPL… not bad at all for a septuagenarian, or anybody else these days for that matter. Keith learnt to fly on the Rotax 912-powered Diamond Katana, the Canadian-built but Austrian-designed composite two-seater. I mention this because he did know how to handle, and what to expect from, the Rotax power unit and was quite used to handling fairly ‘slippery’ aircraft. So, about a year ago, he bought a Pulsar XP, an almost natural choice.

The actual machine that Keith bought had clearly been looked after very well and the quality of engineering was, in Keith’s opinion, completed to a very high standard. In retrospect though, a lot of the changes made hadn’t been through a proper design evaluation. Our records, for example, show that we did know about an oil cooler mod and the (nearly) full airways radio/nav kit on board was fully signed-out. However, we didn’t know about the electrically operated flaps, the permanently coupled wing leveller (Auto Pilot) or, pertinent to this accident, the change from the standard throttle set-up offered as part of the original kit. This aircraft, incidentally, had only completed just over 100 hours since its first flight in 2005.

Keith wasn’t happy with the engine on his Pulsar, the power unit was suffering irregular bouts of rough running and, having some experience with the Rotax fuel set-up, he assumed that it was because the carburettors were unbalanced. He decided, back in April, to take the machine up to see whether the problem occurred at any particular rpm. The aircraft is based at Fife Aerodrome, which enjoys a 700m tarmac strip (which I can testify as being in excellent condition) although it isn’t licensed, so emergency services are only offered on a volunteer basis.

Keith’s take-off was very normal and he climbed up into the circuit planning to carry out a touch-and-go. On the downwind he tried to

“I have to say, after talking to the witness and Keith himself, I think that God must have been watching

over him that day as he walked away from the wreckage without a scratch”

reduce power but found himself unable to get the power back much below 3,500rpm; this meant that it was difficult to slow the machine down. Despite this, Keith thought that the best thing to do was to try to slow the aircraft down by raising the nose above the horizon and, fully aware that he would then be flying way behind the drag curve for the machine, carry out an approach ‘hanging on the prop’. The first attempt, using this method of speed control, went awry and he found himself “in the right place – but far too fast to make a landing.”

The second attempt, using the same method, also wasn’t successful but did attract the attention of a local flying instructor who later commented, “I first saw the aircraft approaching the runway at about 45°, it had a very high nose angle, far higher than looked safe, and the wings were rocking from side to side. I had a student with me and I explained that we were about to witness a crash.” As it turned out, Keith realised that things weren’t going well and aborted this landing attempt too.

Third go! Well, this was pretty much like the first two although he found himself in the correct position over the threshold, “a little slow but too high for a flare.” The observing flying instructor, now positioned in the aerodrome fire engine, takes up the story. “It was clear that this pilot was in trouble, the aircraft was flying at, or at least just above, the stall all the way down

the approach. I’m not sure what sort of height he was when he reached the runway threshold, perhaps 15 to 20ft, although he was far too high to flare. Then, quite unexpectedly, the engine went to full power (the usual Rotax default to full power problem), the nose rose still higher, the aircraft stalled and entered a spin with the left wing hitting the ground.”

I have to say, after talking to the witness and Keith himself, I think that God must have been watching over him that day as he walked away from the wreckage without a scratch. Keith thinks that his other hobby, ice dancing, had prepared him well for the impact; apparently he’s spent quite some time on his bottom pursuing whatever perfection ice dancers pursue!

So, space is running out, what’s to learn. Well, in both the instances we’ve discussed

in Safety Spot this issue, the pilots encountered an in-flight emergency. The Kolb pilot thought that his controls were jammed and reacted accordingly but, after the initial ‘fight or flight’ response (Get Back On The Ground, And Fast) had been made he didn’t check the pitch control to see if the jam had cleared itself. In other words, when the situation had stabilised itself, no re-assessment was made. Same with the Pulsar captain, although this chap had a lot more time to reassess, he never put this on the agenda.

Actually, dragging an aircraft in over the threshold ‘on the prop’ is a well-known, but for experts only, method of carrying out a very short landing; it’s not a sensible way of controlling airspeed if you get a stuck throttle. Two other options that Keith would have considered are: 1) climb above the airfield and, after letting everybody know what you’re doing, switch the engine off and carry out a dead stick landing. No big deal. And 2) come in fast on the approach and switch the engine off when you’re absolutely sure that you’ll get in… if 700m isn’t enough fly to a bigger airport, tell D&D what’s happening and they’ll assist you with your best options.

The other lessons shared between the two events include the consequences of when mods that should have been done weren’t, and mods that shouldn’t have been done were. That aside, both pilots, one very young and one not so young, were both new to our sport. When you, with all your experience, see them struggling a bit, don’t leave them to it; keeping people safe when operating an aircraft is what the LAA is all about. It’s an Association thing. Fair Winds. ■
