Prop strike yesterday (and propeller specific noise level)

That Mooney noise story is another typical grotesque authorities ping-pong. We are still in a fight with LBA plus EASA about our noise test issued in 2010 by OUV we did in Augsburg by flying the Chapter 10 procedure, meaning having a certain overflight altitude and full power climb from a defined distance from microphone. We got 84.7 dB as there is a planetary gear on the Yak 18 T engine and two blade wood prop at 2,5 m diameter. This was accepted for many years when on our airfield the official representative of the Bavarian aviation authority no longer accepted the OUV document. This was allright many years for the LBA as OUV did the paperwork to LBA standards. But in 2013 we converted from Russian register to German LBA to get real legal . At that time they issued 88 dB noise from default ICAO limits, ignoring our OUV 84,7 dB. We did not care much at that time as landing fees were set by checking the OUV papers in all places. Last year only LBA issued papers had to be so we wanted them to change numbers from untested 88 dB ICAO to real test 84,7 dB from OUV papers. But LBA staff refused to cooperate saying the aircraft is “listed” at EASA with 88dB ICAO . After some months of paper exchanges with some EASA staff it appeared that EASA has no procedures for single private aircraft and turned us back to LBA for new papers, but certainly collected € 505.- at the beginning of our EASA experiment – not saying that in all likelyhood we would not have much of a chance of getting anything done – below € 3000.- and an EASA accepted new test flight by one of very few companies willing to do that immense paperwork of today. So our headscratching deals with ideas how to get that Yak removed from that ominous Excel file “listing” it at EASA, just 4 of Yak 18Ts in there from about 50 flying in West Europe, some more in Germany, not just 4 including ours in there. What use is this file at all when only a fraction of all aircraft flying in EU is listed ? In the Mooney case there are lots of them in that file, with Hartcell props and various noise numbers, question is what to do with them in your case ? Anyway, as long as the aircraft is below 88 dB ICAO standard there is no limitation in use apart from high landing fees and limited times for takeoff, like weekend lunch hours. For Germany the limit is 85 dB for reduced fees and our tested 84,7 dB would qualify , just LBA and EASA play ping-pong for getting around of doing anything at all. Vic

EASA noise file

Lovely looking aeroplanes…

Analog tach readings are notoriously off, often by several 100 RPM at the top end. If you have an analog tach, it may be worth while to get the RPM on the tach calibrated. I used to use a handheld device https://www.aircraftspruce.com/catalog/topages/trutach.php. In my Bonanza, the tach was off by 150 RPM when I switched it out to a digital tach.

An idea maybe MD, you could see if a flying club in France would be interested in renting your airplane for the season, this way it gets to be flying while you try to source a 2 blade propeller.

This is a tragic story which illustrates how few people in the GA industry will look after you properly. You really are on your own.

Going N-reg is not easy, and never was. But DARs do exist and are available.

There are a handful of Mooneys in that EASA Excel Calculator file with your propeller. Seems they did the Chapter 6 overflight tests at around 75 dB. Big question is if this is useful in your case. I don´t see a way to find the owner in this excel and EASA will not tell. So maybe Hartcell could point you to an owner with that prop . A noise test to EASA ideas may be more than € 3000.- , not many companies do this today . So I don´t think we will continue with our fight with LBA / EASA as our airfield has returned to accepting the OUV certificate at 84,7 dB below the LBA limit of 85 dB for qualifyling for reduced landing fees. In my country this limit only applies to airfields with more than 15 000 landings per year. Vic

Mooney_Driver wrote:

One of the things which got suggested to me is to find other M20C with that exact propeller, namely the HC-C3YR-1RF/F7282 and see what noise certificates they have. So if you know any M20C with that prop and a noise certificate, please let me know.

Chances are that this combination of prop and airframe has never actually been measured. So the other step we are looking for is to have that done.

M20C with that exact propeller is in the EASA noise certification list, with a Chapter 10 value of 85.5 dBA. So I’m afraid it has been measured. It also seems you will get 2 kg additional MTOM (1170 kg) with that prop…

Airborne_Again wrote:

M20C with that exact propeller is in the EASA noise certification list, with a Chapter 10 value of 85.5 dBA. So I’m afraid it has been measured. It also seems you will get 2 kg additional MTOM (1170 kg) with that prop…

What happens if you measure if with approved organisation and it shows less?