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Rotax 91x at TBO


ianboag

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Section 12.6 of RAA tech manual....

 

Link for manual https://www.raa.asn.au/storage/2-raaus-technical-manual-issue-4-single-pages.pdf

 

SECTION 12.6 PISTON ENGINE CONTINUING AIRWORTHINESS REQUIREMENTS 1. INTRODUCTION

 

1.1 The following is the minimum required by RAAus to show that an adequate and reasonable inspection has been carried out in order to track the performance of an engine.

 

1.2 Although RAAus recommends that the engine manufacturers’ overhaul schedules be followed, “On Condition” operations may be an option, unless the manufacturer specifically excludes it.

 

2 DEFINITIONS – FOR THE PURPOSES OF THIS SECTION Airworthy - an aircraft engine, including its component parts, is generally defined as Airworthy when it:

 

(a) remains as originally manufactured, or incorporates factory approved modifications; and/or

 

(b) is overhauled at the manufacturer’s specified times; and

 

© is overhauled IAW the manufacturer’s specifications; and

 

(d) remains in a condition for safe operation “On-condition” maintenance means an inspection/functional check that determines an item’s performance and may result in the removal of an item before it fails in service. It is not a philosophy of fit until failure or fit and forget. “On-condition” is not available for LSA unless the manufacturer states otherwise.

 

3 APPLICABILITY

 

3.1 Piston engines and those components necessary for the operation of the engine installed in aeroplanes and maintained in accordance with the manufacturers schedules or an alternate schedule approved by RAAus. RAAus TECHNICAL MANUAL Section 12.6 -2 ISSUE 4 - AUGUST 2016 3.2 This section is not applicable to compression-ignition (diesel) piston engines using fuels other than Avgas or Mogas, or electric battery powered motors.

 

4 REQUIREMENTS FOR ALL AIRCRAFT

 

4.1 To ensure the continuing airworthiness of the engine, and those components necessary for the operation of the engine:

 

(a) the requirements of normal servicing, in accordance with the manufacturers schedule; is to be undertaken; and

 

(b) the requirements in Annex A & B for four stroke engines must be followed; or

 

© the requirements in Annex C for two stroke engines must be followed; and (d) operating the engine “on condition” is permitted, unless the manufacturer specifically excludes it.

 

5 REQUIREMENTS FOR AIRCRAFT USED FOR HIRE AND/OR FLYING TRAINING

 

5.1 Maintenance on aircraft identified in this Subsection must conducted by conducted an appropriately accredited RAAus L2. 5.2 Moving an aircraft from “Privately Operated” to “For Hire and/or Flying Training”: Any Factory Built 95.32 or 95.55 Aircraft which has been operating privately with an “on condition” engine, must have that engine overhauled or replaced prior to that aircraft being used for hire and/or flying training. The replacement engine must be either:

 

(a) A factory new engine

 

(b) A factory (or factory accredited over-hauler) overhauled engine and has a completed RACR (Recreational Aircraft Condition Report) inspection done by an RAAus L2.

 

 

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Then there is ....

 

AWB 02-1 Issue 1 - On-condition maintenance | Civil Aviation Safety Authority

 

written 2001, updated 2016

 

whatever this extract means ......

 

Manufacturers Recommended TBO

 

Aircraft and component manufacturers can make "Hard Time" recommendations (i.e. removal of items from service at a specified period for overhaul or replacement indifferent of the items current performance condition), usually referred to as Time Between Overhaul (TBO), which specify how long they consider their product should remain in service. These recommendations are based on average utilisation and conditions and usually recommend that the item be fully stripped and returned to the original specifications. TBO's do not normally involve a condition check being done during the items life. The ability to escalate these hard time limitations however, comes from effective condition monitoring - the real basis for "on-condition" maintenance.

 

CASA Recommendations

 

C of R holders should utilise the philosophy of "on-condition" maintenance to detect the onset of failures of such items, particularly when time in-service of these items are in the vicinity of the manufacturer's recommended TBO.

 

Provided that a component continues to meet the documented standard, at the appropriate frequencies, it is considered satisfactory to remain in service. TBOs that are not included in the manufacturers Airworthiness Limitations or in Airworthiness Directives issued by CASA should still be considered, unless substantiation has been collated to show the outcome of "on-condition" inspections are still appropriate for the safe operation of the aircraft or equipment.

 

Where alleviation is permitted beyond the manufacturer's TBO, an example of which would be AD/ENG/4, C of R holders and LAME's must ensure at the completion of the aircraft periodic inspection the "on-condition" maintenance inspection requirements are included on part 1 of the aircrafts maintenance release as "maintenance required".

 

 

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All that means is that any component subject to "on condition" service, should be regularly inspected to determine whether or not it's condition is still acceptable, and that "on condition" does not mean just leave it in until it fails.

 

For example, the engines in the helicopters I work on are run on an "on condition " basis. They are not just forgotten about because they don't have a fixed service life.....they are subject to regular borescope inspections, spectroanalysis of the oil ( for any particles which might indicated an impending failure), chip detector inspections and power checks ( to make sure there has been no unacceptable decrease in available power).

 

All these things determine the 'condition ' of the engine, should they deteriorate to an unacceptable level, they are replaced.

 

According to the RAA rules, if the aircraft is not used for training, and the manufacturer does not specifically exclude "on condition" operation, then you may operate your engine "on condition", providing you monitor it regularly for further deterioration.

 

The link to the RAA tech manual tells you what type of inspections and the frequency they must be carried out.

 

 

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  • 2 months later...
What happens to aircraft in this situation in Oz? RAA private use ultralights.Do you stop flying and throw the engine away or what?

Hi Ian,

Seems according to TECNAM and Solo Wings the answer is yes. Our Tecnam P92s has a 912 ULS with about 850hrs. We thought when we bought it that it had 2000hrs and would see us out. Now it seems it has 1500 BUT a calendar TBO of 12 years. Currently that gives us another 18 months but we never knew about this and to say we are pissed is an understatement. Also there is a Service Information Letter (SIL-2016-01) issued by TECAM Jan 6 2016 for Oceania engines that changes the mandatory calendar TBO to recommended. BUT apparently CAA in NZ are ignoring this. Please have a look at a Face Book page we have set up to try and organise NZ owners. Please spread this about. We need all ROTAX owners to be aware but we thin many aren't. Rotax New Zealand Owners

 

What happens to aircraft in this situation in Oz? RAA private use ultralights.Do you stop flying and throw the engine away or what?

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Rotax always had this expiry of life based on years. It wasn't shouted from the hilltops but was never a secret, either. Some engines and other items have a "shelf life" as well.. It's common in aviation. Nev

 

 

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According to the RAA rules, if the aircraft is not used for training, and the manufacturer does not specifically exclude "on condition" operation, then you may operate your engine "on condition", providing you monitor it regularly for further deterioration.

but not for LSA, as below:

 

On-condition” is not available for LSA unless the manufacturer states otherwise.

 

Now it seems it has 1500 BUT a calendar TBO of 12 years. We thought when we bought it that it had 2000hrs and would see us out. Now it seems it has 1500 BUT a calendar TBO of 12 years. Currently that gives us another 18 months but we never knew about this

check the Rotax documentation, some are 1500hr/12 years and some are 2000hr/15 years and some 1500hr can be upgraded to 2000hr by doing a modification to the oil pump relief valve, if it has the later type crankcase (check serial numbers).

 

 

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Seems that the calendar life has been around for years but many owners don't know. Spoke with a friend today who has a year old Super STOL with a 914 (ex 747 pilot) who was unaware of the life. Also we have the SIL from Tecnam making replacement a recommendation which is being over ruled by CAA NZ!. On what authority?

 

 

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The engine maker and the Local Aviation AUTHORITY, would over rule the aircraft manufacturer in deciding engine life. You cannot actually return a used engine to new. Cases and other parts have a fatigue life and remachine limits. Reworked engines are sometimes considered zero hours. That would depend on the type of engine. It's possible some are not "return to zero hours" equivalent of reliability. Nev

 

 

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  • 4 weeks later...
I've got one in the shed if you want to try it? only 5 big ones

Have you still got this 912. Does it still run? How many hours and where are you.Cheers, Robert.

 

 

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