50 hour service
Thread Starter
50 hour service
A question PPPruners may be able to help with.
On the maintenance release of most single engine (Piper) GA aircraft the oil and oil filter is to be changed at 50hrs engine time or 4months whichever comes first.
plus or minus 10%.
I have been told two conflicting views of this.
1. The 10% applies to both hours and/or time, ie you could do it at 55hrs or 4month and 12days.if under the max hours.
2. The 10% applies only to hours. But not the date. ie if due on the say 28/6 then that is the latest it can be done regardless.
Does anyone happen to know which is the correct interpretation?
Aircaft is VFR private category.
On the maintenance release of most single engine (Piper) GA aircraft the oil and oil filter is to be changed at 50hrs engine time or 4months whichever comes first.
plus or minus 10%.
I have been told two conflicting views of this.
1. The 10% applies to both hours and/or time, ie you could do it at 55hrs or 4month and 12days.if under the max hours.
2. The 10% applies only to hours. But not the date. ie if due on the say 28/6 then that is the latest it can be done regardless.
Does anyone happen to know which is the correct interpretation?
Aircaft is VFR private category.
50 hour service
The document you are looking for is AD/ENG/4, specifically appendix A.
The exact wording is:
Requirement A3(a) - At intervals as published by the engine manufacturer with a planning tolerance of plus or minus 10%.
Note that as this is a planning tolerance you would be unwise (from a reg point of view) to continue flying into the 10% without proof you were unable to do the service within the published interval.
This would suggest the tolerance on both time and hours is +/- 10%.
From memory lycoming is 4 months and continental 6 months.
The exact wording is:
Requirement A3(a) - At intervals as published by the engine manufacturer with a planning tolerance of plus or minus 10%.
Note that as this is a planning tolerance you would be unwise (from a reg point of view) to continue flying into the 10% without proof you were unable to do the service within the published interval.
This would suggest the tolerance on both time and hours is +/- 10%.
From memory lycoming is 4 months and continental 6 months.
LycomingService Bulletin No. 480E says to change the oil at 50 hours or 4 months whichever comes first.
AD/ENG/4 Amdt 11 says oil to be changed at intervals as published by the engine manufacturer with a planning tolerance of plus or minus 10%.
Therefore the tolerance should apply to the 50 hours and also the 4 months.
AD/ENG/4 Amdt 11 says oil to be changed at intervals as published by the engine manufacturer with a planning tolerance of plus or minus 10%.
Therefore the tolerance should apply to the 50 hours and also the 4 months.
Thread Starter
Thanks very much chaps. Yes this is what I have always believed too in the past.
I was told by a LAME today that the other interpretation is the correct one which put us into a bit of a spin as the aircraft is away until Monday and the due date is tomorrow. Only has 32hrs since last 100 hourly.
I think the Amdt 11 stating the planning tolerance of is the key here.
Aint PPPrune great at times?
I was told by a LAME today that the other interpretation is the correct one which put us into a bit of a spin as the aircraft is away until Monday and the due date is tomorrow. Only has 32hrs since last 100 hourly.
I think the Amdt 11 stating the planning tolerance of is the key here.
Aint PPPrune great at times?
Full marks Progressive, that is exactly what it says. I would say though, that you are correct in what it says, so no suggestion is needed. "at intervals as published by the engine manufacturer with a planning tolerance of 10%." Lycoming SB480E for example is where the 4 months comes from. It specifies the intervals of certain hours or 4 months maximum, but then CASA turns up waving AD/ENG/4 and adds the 10% to the "intervals published" (in this case, hours AND months are those intervals published.)
You may notice a slight difference in the wording within Appdx A Requirement A2 regarding 100 hour intervals for cyl leak check. This one only and clearly specifies plus/minus 10 hours planning tolerance, with no calendar bonus and no mention of "intervals published" - just the hours.
The devil is in the detail.
Case closed, home for tea and medals Progressive!
Great question Mostly T. Download those docs and examine over tea and scones.
You may notice a slight difference in the wording within Appdx A Requirement A2 regarding 100 hour intervals for cyl leak check. This one only and clearly specifies plus/minus 10 hours planning tolerance, with no calendar bonus and no mention of "intervals published" - just the hours.
The devil is in the detail.
Case closed, home for tea and medals Progressive!
Great question Mostly T. Download those docs and examine over tea and scones.
The planning tolerance applies to both the calendar number and hours number specified in SB480E.
It would be typical CASA stupidity if CASA asked for proof that you were "unable" to do the service at a narrower point in the tolerance margin. I am unable to do the service until 54 hours because I'm on the way back from a long trip, and apparently that's "safe". I could have done the service at 52 hours and go on an hour flight instead, then do the service at 53 hours, but apparently that's "unsafe".
Ask them what a "month" is....
BTW, the usual mistake made with ths stuff is to forget to enter in the MR the requirement for the next service after the first service is done post-MR issue. E.g MR is issued on 1 January at 1,000 hours TIS with an endorsement for oil and oil filter change due 1 May or 1,050 hours TIS +/- 10%. Service done on e.g. 1 May at 1,040. The MR should be endorsed for another service due 1 Sep or 1,090 hours TIS +/- 10%, because that falls due during the period in which the MR remains in force.
It would be typical CASA stupidity if CASA asked for proof that you were "unable" to do the service at a narrower point in the tolerance margin. I am unable to do the service until 54 hours because I'm on the way back from a long trip, and apparently that's "safe". I could have done the service at 52 hours and go on an hour flight instead, then do the service at 53 hours, but apparently that's "unsafe".
Ask them what a "month" is....
BTW, the usual mistake made with ths stuff is to forget to enter in the MR the requirement for the next service after the first service is done post-MR issue. E.g MR is issued on 1 January at 1,000 hours TIS with an endorsement for oil and oil filter change due 1 May or 1,050 hours TIS +/- 10%. Service done on e.g. 1 May at 1,040. The MR should be endorsed for another service due 1 Sep or 1,090 hours TIS +/- 10%, because that falls due during the period in which the MR remains in force.
