Choosing a Light Sport Aircraft (LSA) – 3 – primary safety

Safety 01Probably the single most important factor in choosing an aircraft is safety – and it’s usually the most overlooked and under-rated aspect of an LSA.

I remember (old geezer that I am) when motor car companies said that ‘safety doesn’t sell cars’ and they concentrated on looks, acceleration, top speed, road holding, even comfort. Volvo was just about the only company selling safety in their vehicles and as a result gained a reputation as a safety conscious, old people’s car, which has taken years to shake off. If they ever have.

Nowadays, all car manufacturers – not just Volvo – tell you how crash-resistant their vehicles are, how many airbags they have, how anti-skid the brakes and steering are. They have things like traction control and other electronic devices to get you out of the trouble your excess speed or other stupid behaviour just got you into.

So, what about Light Sport Aircraft safety? There are two main aspects to consider: primary and secondary safety. ‘Primary’ refers to the way the aircraft is designed to reduce the likelihood of an incident or accident happening in the first place. ‘Secondary’ refers to the aspects of the aircraft which reduce the effects of  an incident or accident.

Aircraft primary safety can broadly be grouped into ground handling, take-off, stalling & spinning, and landing.

Ergonomics 02But first – ergonomics
Ergonomics are a good place to start, because if they are wrong for you, it doesn’t really matter about the rest. Start with something completely counter-intuitive: how quick and easy is it to exit in an emergency like an engine fire? How easy is it to release the safety belt, open the door and hop out? Think: can I comfortably sit here for 2-3 hours and fly the aircraft? Are you cramped with a passenger on board? Can you still easily operate the controls to their limits with someone else next to you? If reaching a control, adjusting an instrument or even just looking outside the aircraft are a chore, these activities will soon be minimised and put in the ‘can’t be bothered’ basket and as a result, your safety will be compromised.

On the ground
Next, on the ground: how well does the aircraft steer and brake? It is well known that taildraggers are trickier to steer and brake than nose-draggers. But less well known is that some nose wheel aircraft can be a bit of a handful too.

Whereas most taildraggers steer via feet-operated differential main wheel brakes with castering (and sometimes steerable) tailwheels, most modern nose wheel aircraft steer more directly through rudder pedal couplings to the nose leg. This has the advantage of more directional control when the wheel is on the ground. But a potential disadvantage when landing in crosswinds, as the nose wheel may not be pointing in your direction of travel when it touches down. Castering nose wheelThis can lead to bent or even collapsed nose legs. So some aircraft designers have stuck with (or even reverted to) castering nose wheels, steered by main wheel differential braking – either by feet or hands. This gives slightly trickier ground handling especially when it’s windy but reduces the chances of bent gear when landing cross wind. Castering nose wheels usually have a smaller turning circle than direct steering, a particular advantage when back-tracking and turning on narrow runways. There are advocates of both systems – try both and take your choice.

In the air
First, take-off. When applying power for take-off, all single engined aircraft pull to one side due to the combined effects of gyroscopic forces from the engine and propeller and sometimes the spiralling airflow over the tail. Some aircraft have the engine offset so that it points to one side or the other to help minimise the pull – which can look a bit odd from some angles. Correcting the pull should be easy, through application of opposite rudder. However, some aircraft have a much stronger tendency to swing than others. Check out this effect and make sure it is controllable – particularly (eg) if the engine pulls to the left and the wind is blowing from the left, both of which will conspire to turn you off the runway if you don’t take prompt corrective action.

Stalling

stallingWhat about the stalling characteristics? Most LSAs stall very benignly, the nose goes down gently and rarely does a wing drop – something caused when one wing loses lift before the other, for a variety of reasons, but usually because the aircraft is being flown out of balance, with the slip ball not centred. Stalling with a wing drop is most dangerous when making that low-level turn onto final approach before landing. There are a few aircraft which can bite unexpectedly when stalled – if you are an experienced pilot and aware of what’s happening, prompt action can save you. But if the characteristic is particularly vicious and/or you are a low-time pilot, the chances are you won’t survive a finals turn stall with a wing drop. Check this aspect of the aircraft with someone familiar with the type and maybe even ask an instructor to take you up high and try stalling in turns.

Now look at the relationship between stall speed and flap limiting speed. I know of at least one LSA where the stall speed without flap is less than 10 knots below the flap limiting speed. Think about it: you’re coming in to land and you can’t lower flap (eg) until 55 knots. Your stall speed without flap is 45 knots. So you don’t have much margin of speed in which to get the flaps down. Personally, I’d want an aircraft where the ‘clean’ stall speed is at least 40-50 knots below the flap limiting speed.

Spinning
Spinning is really just a stall with maintained wing drop. When I learned to fly, spin recovery was on the syllabus. The aircraft I started to learn on was a Piper Colt, which was difficult to spin – the best you could get out of it was really a spiral dive. To make sure we knew how to recover properly from a spin, we were all taken up in a Beagle Terrier – an excitable little aircraft whose bite was far worse than its bark! Nowadays you aren’t allowed intentionally to spin an LSA and spin recovery training has been replaced with ‘incipient spin’ recognition. Because unintentional spins almost always happen when the pilot’s attention is absorbed with something else, I personally believe spin recovery should be taught as part of basic training, even though most (but not all) LSAs are spin-resistant. At least you will learn instinctively to apply opposite rudder to stop the spin and then raise the nose and apply power. Check out how easy it is to spin your preferred LSA – the manufacturer is required to have carried out spin testing as part of the ASTM certification programme.

Landing
Approach speeds vary a lot with LSAs. Some require at least 65-70 knots down final, others as little as 40 knots. The faster the landing speed, the more wear and tear on the aircraft and the faster things happen if they go wrong. So in the same way you wouldn’t get into a Ferrari to learn to drive, so you shouldn’t get into a fast aircraft to learn to fly! Build your skills in slower gentler aircraft before taking on the trickier ones. And anyway, you might find you like going slow!

LandingWhen assessing the aircraft’s landing characteristics, it’s important to check the correct approach speed – take it up to 3,000 feet AGL and try a few stalls. Note the indicated stall speed. Your approach speed for a low inertia aircraft like an LSA should be around 150% of that speed – much faster and you’ll float all the way down the runway; much slower and you risk a low-level stall. For example, the Foxbat indicated stall speed in landing configuration at maximum weight is in the low 30’s knots; approach speed therefore should ideally be around 50 knots. The factory manual actually says 49 knots. With one person and half fuel, stall in the Foxbat is around 26-27 knots – so approach speed can safely be reduced to 40-45 knots.

When landing, also look out for elevator authority. At least one LSA ‘runs out’ of elevator at landing speeds only slightly slower than its pilot manual advises. This can lead, at best, to a heavy landing; at worst to broken landing gear, because you can’t arrest the downward momentum without applying quite a lot of power. Usually, the reason the elevator loses its bite at slower speeds is because its travel has been limited so as to minimise the effects of inadvertent stalls – the downside is the loss of elevator authority when landing slowly.

In summary
Ground handling and flight characteristics of all aircraft are a compromise, based on what the designer/manufacturer is trying to achieve. Undoubtedly, current LSAs are among the safest handling aircraft available – after all, they mostly incorporate the latest computer-aided design techniques, they stall gently and are spin-resistant. But there are still a few mongrels among them.

Opinion about ‘pleasant’ and ‘unpleasant’ handling aircraft will always be divided so don’t rely on someone else’s personal preferences. Out there is an aircraft for you – fly as many different types as you can, if possible for at least an hour each. That way, you’ll begin to get the feel of the primary safety characteristics you like.

Next – secondary safety.

Choosing a Light Sport Aircraft (LSA) – 1 – what about weight?

Baggage 2Want to buy an LSA (Light Sport Aircraft)? Well, here are a few ‘buyer bewares’ compiled from stories and experiences of other buyers – the first is weight, probably the single most abused factor when flying light sport (and ultralight) aircraft.

Flying over ‘gross weight’ (ie over the maximum 600 kilos on a landplane LSA) is potentially dangerous and certainly illegal – as you’ll find out if you are ramp-checked. As a result of flying illegally, your insurance will probably be invalid too. It’s no good claiming the seller of the aircraft says it is strong enough to handle higher weights – if you’re over the limit you’re setting yourself up for trouble.

Weight limits on aircraft are a fine balance between strength (stronger usually=heavier) and usable load. Manufacturers set weight limits for a reason – yes, maybe the plane will fly OK over-weight but repeat over-weight flying will weaken the structure much more rapidly. Heavy and/or crooked landings in particular can wreak havoc on the landing gear if the aircraft is over its landing weight limit. Flying too fast into unexpected turbulence can also weaken the wing structure over a period of time.

So, what will your preferred aircraft actually carry? As an example, the A22LS Foxbat factory-quoted empty weight is 295 kilos. That’s a standard spec aircraft with oil and coolant in the engine and the starter battery in place. Plus all the essential instruments for safe flight. In reality, the A22LS Foxbat typical empty weight is around 305-310 kilos or even as much as 325 kilos for one fitted with a ballistic parachute. This is because a whole variety of ‘essential’ extras and options are added by owners: different control systems, VHF radio, UHF radio, extra instruments, transponder, autopilot, fuel injection engine, heavier propeller, wing strut fairings, landing light, strobes, big wheels, wheel spats, cabin heater etc etc.

Deduct the actual empty weight of the aircraft from the maximum gross and you get the usable load. This is the bottom line weight you have available for people, baggage and fuel.

Here are a few things to check before committing your hard-earned dollars:
– what is the real empty weight of the aircraft with all the extra bits and pieces you want added?
– does the original quoted empty weight (before extras) include oil, coolant, battery and all essential instruments? Get a signed statement from the seller to confirm.
– how much does that leave you for:
– people, bags and fuel?
– headsets?
– tie-down kit?
– maps/ERSA/iPad/GPS?
– water to drink & food to eat?
– aircraft weather cover?
– a litre of fuel weighs around 0.72 kilos. After deducting the weight for yourself and a passenger, what weight is left for fuel?
– how many litres is that and how long/far could you fly on that amount?
– or, after filling full of fuel, what’s left for people, bags and all those bits and pieces?

As an example – full fuel (long range tanks) in the Foxbat weighs just on 80 kilos, so a starting rule of thumb for the A22LS model is that it will carry around 200 kilos of people and bags after filling with maximum fuel. Every litre less fuel gives you about 0.72 kilos more for people and bags – eg: 20 litres = about 14.5 kilos.

So in summary – flying over gross weight can cost you, in order: your life, your health, your license, your money. Not to mention grief for your loved ones when something breaks and you are injured or worse. In the eyes of the law, ignorance is no defence.

For those who want to learn more, here’s a link to an excellent article on PilotFriend website which gives a lot more information about the risks of flying overweight: Aircraft weight and balance

Check out your true empty weight, your load, and fly safe!

Aero-towing with the A22LS Foxbat

Glider s (23 of 37)Last February [writes Roger Brown, Chairman of the the Vintage and Classic Glider Club of New Zealand] the Club was to hold its Annual Rally at Taumarunui. However due to unforeseen circumstances the tow plane that we were to be operating with ‘fell over’ less than half a day short of our rally starting. A Recreational Light Aircraft, a Foxbat, was generously offered as its replacement by the Foxbat NZ Distributor [LiteFlight Green]. The Vintage Kiwi team gratefully accepted the kind offer and thus were able to continue with the rally and have a great week’s flying.

This is my own personal view of having used the Foxbat as a glider tug for that week and the increasing use of Recreational Light Aircraft in that role here in NZ.

General overview
In all of my years of gliding, I guess there have not been many tow planes that I have not been towed by. However they can be easily grouped into the two main aircraft types that are generally used here in NZ for towing duties as a degree of comparison with the Foxbat.   I have also had a couple of tows behind a high wing Tecnam and several tows with a FK9 Recreational Light over the years so am reasonably familiar with that type of aircraft operation.

1. Piper Pawnee 235/250 hp. Designed as a working agricultural aircraft, (spraying and fertiliser), it is an aircraft that certainly has the capabilities of towing any glider required in any conditions.

2. Piper PA18a Super Cub 150/180 hp. Designed primarily as a private utility aircraft that has also been used for flight training and agricultural work, it has the capabilities of towing any glider required in most conditions.

3. The Foxbat A22 is designed as a low cost Light Recreation Aircraft, but is capable of towing a selection of gliders as required, as I see it.

Tglider towhe Foxbat A22 Specification.
However it is interesting to look closely at the Foxbat’s specs. Because, other than its lower weight and much lower horse power, its wing loading, and speed range is not far short of a big Piper Pawnee which came as a surprise. A design envelope of +4 -2 g would certainly give some confidence. Place into that equation a max cross wind component of 14 knots, a cruise duration of 6.25 hrs plus reserve, a VNE of 120 knots running on 95 mogas and with a 100hp Rotax combined air / liquid cooled engine and you do have a very handy two-seater   light weight aircraft indeed. With an impressive fuel economy which would certainly be one of its big selling points along with an engine life of 2000 hrs TBO, with an achievable initial outlay cost, a Recreation Light aircraft has to be a very tidy package indeed as far as any gliding club treasurer is concerned.

But like the Pawnee and the Cub, it also an aircraft that was not specifically designed to go towing gliders, but it can, and does, and like any towing aircraft, will perform well as long as it tows within its own performance parameters.

Actual Operations at the Vintage Kiwi Rally.
The Vintage Kiwi Rally at Taumarunui attracted some 14 sailplanes including an ASK 21 and a Grob Twin Astir MK3. Other than three pilots who had towed behind a Recreational Light Aircraft before, the rest were flying a little in to the unknown. We used the shorter towrope that came with the aircraft that was successfully used launching at the Drury Champs a couple of weeks beforehand. This worked very well and allowed the Foxbat to easily climb out at 400 – 500 ft per min rate of climb. Obviously with only 100hp on hand there were no real margins to play with in this towing environment, as Taumarunui airfield is surrounded by hills and very high country, so very accurate flying was required by all. Reminded me very much of towing behind a Tiger Moth, same overall skill set applies – accuracy. There was really was no wind for the whole week (only when a thermal came through) and the ground temperature was some 28 – 30 Degrees C – very warm.

The Foxbat was utterly reliable and performed very well. Overall it did a total of 48 launches.   On one day it did some 14 launches.   We were able to launch the ASK21 with two POB, but felt more comfortable with launching the Twin Astir with only one aboard which is where it was felt the Foxbat’s limit was, with this operation, from this airfield, in these hot arid conditions. However, that decision may well have been changed if this combo were flying from a flat and more benign area, such as Matamata as an example.

However, we did have one ‘upset’ at 600ft and one aborted take-off to be fair. The ‘upset was caused by a very powerful King Country thermal that tossed the Foxbat badly off line. The glider pilot released straight away – problem solved. The aborted take-off was caused by low acceleration and a bad wing runner. The glider released – problem solved once again. However after a slightly different approach to the operation by the tow pilot and wing runner, there were no further issues and every one continued to be launched behind the Foxbat absolutely trouble free. I am told that the visibility from the Foxbat is apparently awesome, especially on its way down after release, when one can initiate a very steep descent profile because the engine remains at a constant temperature (no air cooled potential spiking issues here).

[Click here to view a short video about the Foxbat glider towing at the Gliding Club of Victoria, Benalla Airport.]

The Big Question that I have always asked myself is, “Can a Recreational Light Aircraft fit into the NZ Gliding Club scene as a ‘stand-alone’ club work horse?”

For me, the jury is still out – I have to say mainly due to my still limited overall exposure to operating with such an aircraft.   However as far as the Vintage and Classic Glider Club were concerned, it did perform very well with the range of gliders that turned up for that week, and slotted into our operations like a ‘pro’. However we were operating in very good pristine conditions. How a Recreation Light would have performed with a descent gusty cross wind, and with some real wind bouncing off the many hills that surround the airfield I am not sure.

HoKookaburrawever, a club such as Aviation Sports based at the Whenuapai Air force base in Auckland, who have operated a FK9 for a few years now would be far better placed to comment. The Taranaki Gliding Club at Stratford is another club to have gone down the Recreational Light direction having just unpacked their new Eurofox Recreational Light to take over from their big Pawnee, which has now been retired. It should be flying shortly.

The Canterbury Gliding Club has also recently received their new Recreational Light to supplement their operation I understand. So there is defiantly a move into that direction and the next 12/24 months or so will more truly reflect on their towing abilities, as well as their true maintenance and operating costs as the towing hours and cycles start to build up.

However for a small – low hour – club it could also turn out to be the actual saving of such a club just in the sheer economics of operating such a tow plane, all things considered. For a bigger club it would certainly price average their launching and operating costs for their members to benefit from.

Benalla glidersService life span as a tow plane? Who knows, but really who would have thought that clubs would still be operating tow planes that date back to the 1960’s and are still towing with them some 54 years later. I certainly would not have put money on that one, I have to say.

The Vintage and Classic Glider Club of NZ Inc. wishes to thank Ian Williams, and Jim Lyver for bringing the Foxbat down all the way from Mercer and to tow for us. And of course to Doug King, the owner and NZ Distributor for the Foxbat for allowing a group of people whom he had never really met before, to commandeer his aircraft so as to have a wonderful weeks’ – ‘boys with their toys’ – gliding in the heart of the King Country and its amazing soaring areas. We were truly grateful for your support.

Roger Brown, Chairman, The Vintage and Classic Glider Club of NZ Inc.

SportStar flight test – comparison with Foxbat

SportStarHere’s a completely unsolicited flight report on an Evektor SportStar with references to the Foxbat. The flights were conducted early this year at Jandakot Airport, Perth by ‘Birdseye’ and posted on the Recreational Flying Forums – thanks to him for the review.

 

“Well after a visit to look over the Sportstar a week or so ago, I went for a first ride today. A big plus that the BoM advance forecast of 39C and sunny was crap and the day turned out around low thirties, overcast with light winds and smooth air. Who could ask for more when trying a new ride for the first time? Not only that, but WA’s busiest airfield was more like a morgue than a honeypot.

First impressions on taxying out were reminiscent of the Foxbat; same firm rudder. However, without the doughnut golf buggy tyres and variable ground surfaces, it wasn’t at all bad. Then again on similar surfaces the Foxbat may have felt the same. Instantly the low wing visibility made me feel more comfortable, probably due to my earlier power and later glider flying. Had the sun been blazing down, I might have liked the Foxbat more, but the neat sunshade was available in the Sportstar if required.

All the engine management stuff, run up etc. was quite natural. l liked the fuel selector which was reminiscent of the Cherokee. Still some venting issues to consider in its operation, but nice and easy to hand. Panel was close to the trad six pack which I loved and lay out was clear and switches/controls were easy to hand. I’m by no means a luddite and in fact many class me a a techno and lover of gadgets, but I don’t easily relate to the low end glass screens that seem to be the vogue. I’ve used high end EFIS/HSI setups and like them, but these pretty terrain projections etc. really do turn me off due to their ability to distract. Just Too much encouragement to young players to look inside the cockpit. TCAS is great, but not for VFR flyers to rely upon.

The flying? Well I enjoyed the conventionally placed stick and other controls. The electric trim responded quickly and I didn’t spend so much time waiting for it to catch up. The down side? It happened quicker than expected, but I don’t see that as an issue. Otherwise the aeroplane was nicely balanced, easy to trim and gave good performance on its 912 ULS motor. Once practicing steeper turns the low wing massaged my comfort zone; a clear view into the turn gave me confidence that a high wing doesn’t. Just personal preference? Maybe, but its something I felt many years ago switching between a Beagle Pup (say ahhhhhh, a lovely plane in fact much like the Sportstar) and a C150.

Forward visibility was rather better, to the point where I had to check myself from drifting up due to the angle presented by the panel. On climb out only a small nudge was needed to check for a clear path ahead.

So, how does somebody write something like this without upsetting somebody? Maybe not compare directly, just focus on the strengths of each? It would be nice to try a broader range of modern LSA aircraft, but with the incredible range that’s just not practicable. My summary is that both the Foxbat and Sportstar are great aeroplanes, with small differences in their purpose and hence varied attraction to pilots. The Foxbat will get you down on a proverbial fag paper and nobody should ever fear a forced landing in one. Its a little unconventional in areas, that some, including myself may have a problem with. Most will I’m sure be more than happy.

The Sportstar is another well built aeroplane, that will perform at the low end close to the Foxbat, possibly without the pin point short field performance. It suits more what I intend to use the aeroplane for and to me is better for no more than that.  10/10 for both!”

A22LS Foxbat service advisory notice – urgent!

A22LS cardan ring crackSome cracks have recently been found in the Cardan rings on an Australian operated A22LS Foxbat. Although there have been no other reports of similar cracks in the worldwide fleet, because it affects part of the primary flight control system, the factory will be issuing a mandatory inspection requirement and an amendment to the Aircraft Maintenance Manual (AMM). RA-Aus and CASA have been informed.

There are two Cardan rings on the aircraft – these are a type of universal joint – connecting the flaperon control torque tube and the flaperon. They are located just outside the fuselage where the control tube exits the cabin at the rear of the wing – see picture above (click photo for a bigger version).

The cracking is caused by over-tightening the long vertical connecting bolt, possibly made worse by allowing the control surfaces to bang up and down in the wind when the aircraft is parked outside with the controls unrestrained.

Here’s what you need to do BEFORE THE NEXT FLIGHT:

– lower the flaps to their full extent;
– remove the safety pin and loosen and remove the long bolt which runs vertically through the Cardan ring;
– inspect top and bottom lugs of the ring for any cracks;
– if no cracks are found, lubricate and replace the bolt and tighten to 2Nm of torque; don’t forget to replace the safety pin!
– if cracks are found, please contact me at Foxbat Australia on info@foxbat.com.au with clear, in focus pictures of the cracks.

On completion of the inspection, either (a) if no problems are found, record a statement to that effect in the aircraft maintenance log, or (b) if cracks are found, complete an RA-Aus incident report (click this link to get to the form on the RA-Aus website) and send it to the RA-Aus National safety Manager.

If you have any questions about this advisory, please call me, Peter, on 0413 900 892.

Rotax engines (3) waterless coolant

Rotax 2013 cylinder headsIn 2013, Rotax introduced (without much of a fanfare) a new design of cylinder head for their 912 carburettor series engines. These cylinder heads have been fitted to all new engines since then and may be retrofitted to earlier engines.

Having received a couple of queries from owners whose engines incorporate the new heads, it is important to understand that you cannot use waterless coolant in conjunction with these heads.

In addition it’s worth noting the following:
– the new heads are similar to but not the same as those fitted to the 912iS fuel injection engine. If you have to replace cylinder heads, make sure you get the right ones.
– the CHT sensor is in a new location
– what was the CHT sensor now measures coolant temperature not cylinder head temperature. You therefore have to use a new coloured-arc temperature gauge to reflect the correct coolant (not CHT) temperature limits.
– the sensor screw must be sealed with Loctite as the sensor is now immersed in coolant; the earlier CHT probe fitted into a dry void in the cylinder head.
– the cylinder head bolts must be torqued to a different value from the old ones, and also in a different order.

You can access detailed information about these cylinder heads in at least three places:
(a) Rotax Service instruction SI-912-020
(b) Rotax Line Maintenance Manual temporary update
(c) ‘Rotax Minute’ video, which briefly describes to differences between old and new design cylinder heads (may be Rotax can change that awful voice over??)

 

Rotax engines (2) carburettor floats

Rotax carby floatsAt last Rotax has issued a final service bulletin covering replacement carburettor floats. For those not fully up to speed on this, Rotax has had a problem with ‘permeable’ carburettor floats on most recent 912 series engines. Basically any faulty floats absorb fuel and sink to the bottom of the float chamber, causing rough running and potentially overflowing fuel. Floats on affected engines had to be checked every 25 hours and if needed, replaced.

The latest service bulletins (click on the numbers to see & download): SB-912-067 and SB-912-067UL list the affected engine numbers and necessary actions.

In addition, Rotax has posted information on their blog about how to get your replacement floats.

In Australia, contact Bert Flood Imports – phone 03 9735 5655 – near Melbourne, give/send them your engine number, and they will send you replacement floats and an invoice for them. Returning the old floats quickly together with the invoice will result in a refund/credit or cancellation of the invoice.

Hopefully this will see a conclusion to the concerns over faulty floats.

Rotax engines (1) scheduled service intervals

Rotax serviceOn what basis do you record your times for scheduled services on your Rotax engine? Engine running hours – start to stop? Starting to taxi to stopping – wheels turning to wheels stopping? Flight time via an air switch – wheels off to wheels on the runway?

At bigger and/or busier airfields there could easily be a big cumulative difference between engine start/stop and wheels off to wheels on the runway – as much a 25% or more by some LAME accounts. So what is the correct procedure for recording times to determine scheduled maintenance on your Rotax engine? The answer, it seems, has been about as clear as year-old engine oil!

The initial response from the Rotax service department to my query was that maintenance must be carried out based on engine running time as recorded by ‘an electronic engine hours timer’ – ie start-up to shut-down. This is different to some of the statements in their maintenance manuals and certainly not the way most flight schools and clubs record time for engine servicing; they usually use take-off to landing times for overhaul.

Please note:
What follows has now been superseded by the following: all Rotax engine scheduled maintenance times are currently based on engine running times – ie from start up to shut down. Therefore, for maintenance purposes, record engine running times accordingly. Also check to ensure that the airframe manufacturer aligns their mandatory maintenance schedules with the engine maintenance requirements. Most of them do – including Aeroprakt.

Please also see my updated blog post on scheduled maintenance times: https://foxbatpilot.com/2017/04/12/rotax-engines-4-scheduled-maintenance-update/

When questioned a little more, Rotax finally clarified that their engine scheduled maintenance times comply with standard FAA (and CASA) practice – that is, take-off to landing time, ideally measured with an air-switch hours meter. I now have this in writing (by email) from them, so if you or your engineer need written confirmation, let me know.

So, repeating, for the sake of avoiding all doubt – record your engine scheduled maintenance times from take-off to landing. Maybe even fit an air-switch-operated hours counter if you need to. In the long run, this can save you quite a lot when it comes to servicing, likely well more than the cost of fitting an air-switch.

PS – Don’t forget: if you are late with a service – eg 55 hours instead of 50, the next service is still due at 100 hours, not 105. Read the Rotax manuals!