Light Sport Aircraft Maintenance

It is my belief that today’s recreational and light sport aircraft need more careful and meticulous maintenance than traditional ‘rag & tube’ ultralights and typical single engined GA aircraft.

Over the last 15-20 years or so, recreational and light sport aircraft have become much more GA-like in their looks and construction, compared with traditional utralights of old.

Their weight and complexity has increased almost beyond the imagination of early ultralight owners; their airframes have become more and more GA-like, with concealed control systems, engine bay ducting which hides many key engine components, digital instrumentation, auto-pilots and the like. Yet recreational aircraft owners and pilots are still permitted to ‘do all their own maintenance’*.

Crucially, recreational and light sport aircraft have to be designed and built to fit under a specific gross weight limit. There is also a maximum empty weight formula related to the maximum gross, which effectively limits the empty weight of a 2-seat aircraft to around half that of a typical 2-seat GA aircraft. As a result, manufacturers have to do everything they can to minimise empty weight – usually by using light weight materials and making components as strong as they need to be, but no stronger.

This lightweight approach is not in itself an issue – indeed it has enabled the design and manufacture of some wonderful aircraft. But in reality, ‘cheaper and lighter’ means you have to be much more thorough with your inspections and maintenance.

Why?

Because the metal is thinner all round; because so-called ‘carbon fibre’ aircraft actually contain very little carbon fibre (if they really were mainly carbon fibre, their cost would be astronomical); because cables are thinner, because engines are smaller/lighter/more highly stressed, because propellers are typically composite not metal; landing gear is lighter; bearings are smaller, tolerances are tighter; and because some of their systems are quite different from typical GA aircraft, and on and on…

Although RAAus is working wonders to improve the safety of aircraft registered with them – particularly focussing on maintenance issues and authorisations to maintain*, I still have considerable doubts as to the maintenance capabilities of many RAAus Aircraft owners, who likely have little or no aircraft maintenance knowledge and experience. I myself know the A22 and A32 airframes inside out but I do not feel at all confident I could safely maintain one.

For example do these owners know:
– how properly to lockwire a bolt, and what thickness and type of wire is required?
– how to measure and adjust the tension of a control or structural cable?
– how and when to use a torque wrench correctly?
– the standard torque settings for each size of bolt?
– how and when to check static and dynamic carburettor balance?
– how to check the friction on the Rotax gearbox clutch?
– how to make sure the ends of a cable are still securely swaged?
– how to measure correctly the strength of the fabric covering on a wing?
– how to open and examine properly an oil filter after an oil change, and what to look for?
– how to check a control or structural cable for internal abrasion and wear?
– how and where to look for cracks in metal/composite/wooden airframes?
– where to place a jack to raise their aircraft?
– how to decide when to replace an ‘on condition’ item?
– what constitutes ‘acceptable’ and ‘unacceptable’ wear in an item?

Not to mention possession of all the tools needed to do these jobs properly?

Now, I’m aware of many aircraft in our Aeroprakt fleet with well over 3000 hours on them – with no particular problems. As I say, maintained properly, recreational and light sport aircraft can continue flying safely for many thousands of hours.

But if you are going to maintain your own aircraft, get proper training to do so – if you skimp on maintenance or try to save money by doing it yourself when you don’t really have the capability, at the very least your aeroplane won’t last as long as it should. And at worst, it will be your life (or that of the pilot) that’s threatened.

* Owners of RAAus registered aircraft may maintain their own aircraft provided they have an L1 Maintenance Authority (sometimes called an ‘Owner-Maintainer’ authorisation). Details of this are available on the RA Australia website at http://www.raa.asn.au  under the member section ‘Member Training’

A22L Foxbat gross weight increase

I have good news for all Australian owners of A22L (450 kilo MTOW limit) Foxbats!

With the new RAAus MARAP system (Modification and Repair Approval Process), a review to increase the gross weight limit (sometimes called the maximum take-off weight (MTOW)) of RAAUS  registered Aeroprakt A22L Foxbat aircraft from 450 kilograms (472.5 kilograms if a ballistic rescue system is fitted) to 525 kilograms has been conducted and now approved.

During the review of the A22L for an increase up to the 525 kilograms  MTOW there is a small ‘G’ limit penalty: the maximum limits are reduced from +4G and -2G to +3.6G and -1.8G respectively. In effect, this means you need to observe manoeuvring and rough air limits closely to ensure you do not exceed these lower limits.

No structural or other changes are required to the aircraft.

To obtain the increased weight limit on your A22L aircraft, please contact the technical team at RAAus – phone number 02 6280 4700 or email to tech@raa.asn.au – and request the necessary documentation. This includes a supplementary page for your pilot manual and an entry to the manual revisions page.

RAAus will make a charge for this service but I’m sure you’ll find the extra – legal – 75 kilograms well worth it!

Please note, this increase is not relevant to the Aeroprakt A22LS Foxbat, which already has a gross weight limit of 600 kilos and ‘G’ limits of +4 -2

Aeroprakt issues rudder cables safety alert

Example of cable damage


Following two rudder cable breakages on A22LS aircraft, the Aeroprakt factory has issued a safety alert covering all A22 and A22L aircraft with over 500 hours engine running time and all A22LS and A22L2 aircraft over 5 years old or over 500 hours engine running time.

The alert requires an urgent check of both left and right rudder cables to ensure there is no wear or fraying of the cables, particularly close to the pulley guides. If any wear is seen or broken strands are found, the rudder cables must be replaced.

Click here to download a copy of the alert for A22 and A22L aircraft.
Click here to download a copy of the alert for A22LS and A22L2 aircraft.

Australian owners should contact Foxbat Australia for more information or replacement cables. Owners in other countries should contact their local dealer for support.

A32 Vixxen door latches – safety bulletin

Aeroprakt has issued a safety bulletin covering the door latches on A32 Vixxen aircraft, serial numbers 02-28. Compliance with this bulletin is required before the next flight of the aircraft.

Click here or on the drawing above for a copy of the bulletin: SA-A32-03 Door Latches

Rotax 912 series oil filter – new service bulletin

Rotax has issued a new mandatory service bulletin covering their oil filters – SB-912-071.

Due to a manufacturing deviation, the sealer gasket on the oil filter may leak, causing possible loss of oil pressure and oil.

If your 912ULS engine number is within the series from S/N 9 569 542 up to S/N 9 569 782 inclusive, or you have service replaced your oil filter since June 2017, you need to check the filter. If it has a green mark in the specified location, the filter is OK. If not, check for leakage and if any is seen, the filter must be replaced immediately. Even if there is no visible leak, the filter must also be replaced immediately on listed engines.

If there is no green mark on the filter, no leakage and the engine is not listed, the filter should be replaced within 25 engine running hours or within 200 days from 01 November 2017, whichever occurs sooner.

Here is a link to the service bulletin which gives full details: SB-912-071
Here is a link to the listed 912UL & 912ULS engines affected: SB-912-071UL

Urgent Rotax safety bulletin

Rotax has issued an urgent and mandatory service bulletin on their 912/914 series engines. It applies to a limited selection of engines built between June 2016 and October 2017 – check your Foxbat/Vixxen 912ULS engine number against the list below to see if you are affected.

(A) from S/N 6 785 971 up to S/N 6 786 198 inclusive
(B) from S/N 6 786 501 up to S/N 6 787 000 inclusive
(C) from S/N 9 569 001 up to S/N 9 569 690 inclusive
(D) from S/N 9 569 693 up to S/N 9 569 702 inclusive
PLUS S/N 9 569 823

In summary
Rotax reports that deviations in the manufacturing process of the valve push-rod assembly may cause partial wear on the rocker arm ball socket. This wear could lead to a rocker arm cracking/fracture which in consequence may lead to a malfunction of the valve train. Possible effects are rough engine running or an unusual engine operating behaviour.

The bulletin requires the removal of the rocker covers of affected engines and an inspection – and if needed, replacement – of the valve pushrods.

In simple terms, if the pushrod ends are a silver-ish colour, they are OK. If they are black they will need to be replaced.

Time frame for completion of the bulletin is:
– either at the next scheduled service
– or if a scheduled service is not due, within the next 25 hours of engine running time
– or if 25 hours running time is not completed, by 30 April 2018 at the latest

Here are links to the Bulletins:
What needs to be done: https://legacy.rotaxowner.com/si_tb_info/serviceb/sb-912-070.pdf
Which engines are affected: https://legacy.rotaxowner.com/si_tb_info/serviceb/sb-912-070ul.pdf

If you believe your engine is affected, please contact Bert Flood Imports, the Australia Rotax engine agent, for more information.
Bert Flood Imports phone number is: 03 9735 5655

Tie-down rings for A22LS & A32 aircraft

With Aeroprakt factory approval, we have developed a kit of tie-down attachments for A22LS and A32 aircraft. This is available as a retro-fit kit or as an installed option on new aircraft.

The kit consists of all the parts you need to add a tie-down point to the top end of each wing-strut and to the tail of the aircraft. There are full fitting instructions and also a copy of the factory Letter of Approval, which you’ll need, to keep the aircraft legally an S-LSA. Please note – non-approved changes to LSA planes mean they revert to ‘Experimental’ LSA – meaning you cannot use them for flight training and/or hire.

The photo here shows one of the strut rings but click here to take you to the Foxbat photo gallery where there are some bigger, higher resolution photos.

We are also developing a nose wheel tie down plate for use if you have to park your aircraft outside for more than a night or two – watch this space!

Cost of the retro-fit tie-down rings kit is A$295 including GST and postage inside Australia. As a fitted option on new aircraft, the price is A$335 including GST.

NB: this kit is not suitable for A22L aircraft.

Please contact Foxbat Australia at info@foxbat.com.au if you wish to order a kit.