Rotax TBO

[Admin]

The rotax in the Gazelle is certified, it is the 912A engine so to keep it certified it has to have a new crankshaft when rebuilt

 

 

[Guest Maj Millard]

The 912uls is uncertified...the 912 S is certified.

 

 

[Admin]

http://www.flyrotax.com/enginesImpressum/product-rangeImpressum/carburetedImpressum/912-80hpImpressum/description.aspx

[PaulN]

Hi Ian,

 

 

 

Are you sure your Rotax is certified? Mine is ULS which is uncertified.

 

 

 

Crank shaft or crank case? I've been corresponding with Gary at Bert Flood who keeps prattling on about the need to replace the crank case. He says that a full o/haul w/o new crank case will give me a reset to 12 years or 1500 hours, but include new crank case with the o/haul and get 15 years. Seems a bit odd to me ... keep the old crank case, do an o/haul and run another 12 years, that's 24 years with the old crank case or replace it and get just 15 years TB next O. I have to talk with him further for clarification.

 

 

 

BTW, Techman at RA-Aus informs me that we have CASA approval to run our engines "on condition" now, if done iaw Section 12.7 of the new Tech Manual (due for release later in the year). I'll be exploring that thoroughly over the next few days. I know it only delays the inevitable but around $18k for an o/haul (plus crank case if I so elect) or $23k+ for a new replacement 912ULS might require a bit of saving for. Looking at those figures I think one would be bonkers to choose an o/haul rather than new engine (incl new everything ... gear box, slipper clutch, HD starter & relay, full ign system, rect/reg, Bing carbs, expansion tank, SS exhaust sockets, oil filter & tank, coolant pump, 2 CHT sensors, OP sensor and a tool kit ... and with 2000hrs or 15yrs TBO). Apparently comes without hydraulic hoses (oil, coolant and fuel), fittings and fuel pump so these would be another $1000. Also, if chosen, a new SS exhaust system is another almost $1000, plus if chosen new oil and coolant radiators at $750. I wonder if the tool kit is like you get with flat pack furniture, one allen key?

 

 

 

Cheers,

 

 

 

Paul

 

 

[Admin]

Yes Paul but only in the Gazelle

 

 

[PaulN]

What about the crank shaft vs crank case question?

 

 

[Admin]

Not sure but when the engine was rebuilt in the Gazelle Floods didnt replace the shaft so i had all sorts of problems. The Gazelle was no longer a Gazelle without the A rated engine. Had to get a letter of acceptance by the tech manager accepting the downgrading of the A engine to an UL engine. The one negative was the Gazelle couldnt be used for training then because it was no longer a "Gazelle" without the A engine

 

 

[Downunder]

Hi Ian,

Looking at those figures I think one would be bonkers to choose an o/haul rather than new engine (incl new everything ... gear box, slipper clutch, HD starter & relay, full ign system, rect/reg, Bing carbs, expansion tank, SS exhaust sockets, oil filter & tank, coolant pump, 2 CHT sensors, OP sensor and a tool kit ... and with 2000hrs or 15yrs TBO).

 

Cheers,Paul

And you may get 4 or 5 thousand for the old unit......

 

 

[kasper]

What about the crank shaft vs crank case question?

The issue is that not all crank cases are the same on the 912 series - and not even the heads as they have built several different cases and heads, and fuel pumps and ignition units and ... and ... etc (Jabiru are not the only ones to develop their engines over series production)

The 12 year life applies per overhaul on early series engines and the overhaul life in years cannot be extended - you serial number sets the limits. The later cases have 15 years life.

 

So overhaul a 12 year engine and it gets another 12 years, overhaul a 15 year engine and it gets another 15 years.

 

As I think you have come around to the fact is IF you are required to follow rotax life/overhaul requirements because your RAA registered aircraft manufacturer REQUIRES you to follow engine manufacturers overhaul and service requirements THEN the usual sensible option is to replace the engine in total with a new one at end of overhaul life because you will recover more $$$ from selling a time expired 912 to someone who DOES NOT need to follow the rotax overhaul schedule and can either run on condition already (all those 19 reg aircraft and others not used for hire and reward (very complex to work out so this is a gross simplification) or will be able to under new tech manual (?).

 

The new tech manual I understand will extend the on condition running but I will be astounded if it extends to aircraft for hire and reward and would seem impossible to extend to LSA not experimental.

 

 

[PaulN]

Kasper, having only just now spoken with Bert Floods again, I've decided to go for the "on condition" option. They advise that it is not uncommon for a Rotax engine to give many hours of happy performance well beyond the TBO numbers, and quoted an example off the top of his head of one which is still running "on condition" at 5000+ hours.

 

The RA-Aus Tech Manual 12.7 states that running "on condition" is allowed ... "unless the manufacturer specifically excludes it". I've been trying to make contact with Flight Design by emails, phone messages and SMS without any return over this past week So, I guess if I don't hear from the manufacturer they can be deemed as not having "specifically excluded" the option.

 

 

 

I note from the 12.7 doc (cl 4 & 5) that the "on condition" is valid both for private use and for hire/training use, the only exceptions being that in private use the L1 owner may do the work but for hire/training it "must be conducted by a Part 66 licence holder who is also the holder of an RA-Aus L2". This doc also clearly states ... "On Condition is NOT AVAILABLE FOR LSA unless the manufacturer states otherwise".

 

Paul

 

 

[storchy neil]

so what some are saying raa and casa ARE AUTHURIZED TO CHANGE THE ROTAX MANUALS ON ENGINE MANAGMENT AND INSTALATION OF ROTAX 912 ENGINES

 

please show letter off approvel from rotax neil

 

 

[kasper]

so what some are saying raa and casa ARE AUTHURIZED TO CHANGE THE ROTAX MANUALS ON ENGINE MANAGMENT AND INSTALATION OF ROTAX 912 ENGINESplease show letter off approvel from rotax neil

LOL you beat me to that one ... IF a manufacturer in running through their certification process has as part of that process documented that the Rotax manual and service bulletins etc either must be followed and/or incorporated it as part of the operational documentation for that aircraft then the RAA coming along and saying Nope, we know better, go to on condition means in effect that the original manufacturer has a very good case to turn around and say that the certification no longer applies, we are no longer responsibile for continued airworthiness, the aircraft is not our responsibility to a large extent and thanks for the money in buying it from us but the RAA seem to be taking on the technical control of that airframe, chat to them about it ...

brave RAA, very brave

 

At least they do not appear to be saying that LSA can go this way.

 

What is needed - and only this much - is for a way of dealing with old certified/approved airframes where the manufacturer no longer exists and the airframe needs support - thats what I thought the new MARAP process was to provide - in that respect the RAA with the backing of some aeronautical personnel are taking the design role because there is nobody doing it - but to do that to an airframe where the manufacturer still exists is in my opinion 'brave' and unnecessary.

 

 

[planesmaker]

On condition, has been part of the tech manual for a long time now, including for training. Nothing new here, a bit of carry through from GA actually. LSA is different kettle of fish with airworthiness responsibilities lying with manufacturer and what they dictate.

 

 

[ben87r]

Isnt TBO normally a "recommendation" ??

 

 

[storchy neil]

Isnt TBO normally a "recommendation" ??

 

no not if in instalation manual or matenence manual of said manufacture

 

what raa and casa are saying is beyond my abilty to anilisze as they are asserting full responceabilty to the next fatal neil

 

 

[kasper]

On condition, has been part of the tech manual for a long time now, including for training. Nothing new here, a bit of carry through from GA actually. LSA is different kettle of fish with airworthiness responsibilities lying with manufacturer and what they dictate.

Oh do not go there. The RAA manual in this area are frankly cobbled together cut n pastes from various documents that are internally inconsistent and externally inconsistent with both the CAOs and the manufacturers documentation.

eg 1. The current Appendix A for 'on condition' 4 strokes requires you to record the leak down results on 'the maintenance release' ... this is not a document that exists for RAA aircraft ans shows that this part of the appendix was without care lifted from GA

 

eg.2 the same appendix requires that "oil consumption shall be monitored in accordance with approved maintenance data" ... as we don't have a maintenance release to record this on its moot but where are we to get "approved maintenance data" from?

 

eg3 The Tech manual has been in its current form for 8 years ... no Appendix B for 2strokes ... so guys couldn't find a GA text that set out how to manage a 2 stroke eh?

 

Basic point - to remain within the approval for being a factory built RAA registered aircraft its either certified or built by an approved factory to an approved/accepted design. If that design documentation requires that the engine be a 912A then putting a 912ULS in makes it no longer comply ... unless you have a reg 35 engineer (out of date name but you known what I mean).

 

If that 912A is documented in the acceptance process by CASA to have the rotax manual incorporated not following it also makes it no longer meet the design requirements to be operated in the original category ...

 

This minefield is not new and for the most part its been pretty much ignored but its there as an issue.

 

 

[facthunter]

Without approval either timex eg 100 hourly/ one year or over TBO doesn't happen. No if's no but's.

 

"on condition" is a dog's breakfast. It's not done properly by just doing compressions.

 

IF you get metal in the filter, beyond a small "Normal" amount, it's an engine strip anytime. Same with an engine overspeed. Depending on where it goes to on the dial it's a life reduction or a rebuild or a SCRAP engine situation..

 

Some TBO's come from a manufacturer's imagination wish list, and are close to meaningless. Failures below TBO if significant enough in number, would be expected to cause a reduction of the TBO..

 

There is a practical limit to operate any engine part (example crankcases) They have to be decked and align bored and sometimes welded I wouldn't run any DHav Conti or Lyco over second rebuild. I've seen plenty with large cracks in first life engines. You heat treat the casting/forging prior to machining. You can't redo it without risking a lot of warping.. With aero stuff new is beaut..Nev

 

 

[PaulN]

[Quote ... RAA coming along and saying Nope, we know better]

 

Kasper ... the RA-Aus 12.7 doc addresses your concern by clearly including the disclaimer "... unless the manufacturer specifically excludes" the option of going 'on condition'.

 

[Quote ... eg 1. The current Appendix A for 'on condition' 4 strokes requires you to record the leak down results on 'the maintenance release' ... this is not a document that exists for RAA aircraft ans shows that this part of the appendix was without care lifted from GA

 

eg.2 the same appendix requires that "oil consumption shall be monitored in accordance with approved maintenance data" ... as we don't have a maintenance release to record this on its moot but where are we to get "approved maintenance data" from?

 

eg3 The Tech manual has been in its current form for 8 years ... no Appendix B for 2strokes ... so guys couldn't find a GA text that set out how to manage a 2 stroke eh?]

 

Kasper and Planesmaker ... As mentioned earlier, the new Tech Manual is due for release later this year, so while discussing stuff that we've been given a heads-up on that will be included, comments based on what has been before may not offer clarity for followers of this thread. The 12.7 doc does provide for two stroke engines and does provide a Tech Form 023 - Piston Engine Condition Report for the L1 or L2 to complete and sign off at each normal service interval (50hr, 100hr, annual). This is to be to be included as part of the aircraft's engine maintenance record (log book). Engine performance specs requiring testing and reporting are ambient air temp, location altitude, static MP, MP at t/o power, max RPM at t/o, fuel pressure at idle, fuel flow at idle, fuel pressure at t/o power, fuel flow at t/o power, oil pressure at idle, oil pressure at t/o power, oil temp at idle, oil temp at t/o power, oil consumption, cylinder compression and leak down and oil filter screen check for metal bits. This "on condition" doc stipulates some parameters that must be observed noting that any variation beyond said parameters or the obvious alarm of metal bits in the oil requires that the aircraft is not to be flown until corrective action is taken, which may include o/haul or replacement. Personally I'm inclined to add to this list for my engine CHT, EGT and gear box overload clutch data.

 

Yes it is similar to GA world and yes, I think Darren's done a good job with this.

 

 

 

Paul