Did some work on the 337 today at my IA shop. He does maintenance for a small but busy flight school. He’s got a few filters but they’re depleting faster than what few come in. He’s already purchased some K&N’s. When the time comes (soon) he’s going to call the FSDO and tell them there’s no choice, will have to use K&N Or ground some flight school and number of corporate planes he takes care of on the field as well as personal aircraft. Busiest airport in the state, so not a small following might back that up. Also, we discussed “owner manufactured” parts solutions allowed by the regs when nothing else available. Alternative is that this be considered owner “manufactured” part solution. I guess you can document it that way.

Found this interesting in Cessna flyers:

https://www.cessnaflyer.org/maintena...lications.html

AC 23-27 & AC 20-62() provide good information on this topic.

See attached.

Thanks LearJetter, the documents are helpful. They mention having data available for the part you wish to substitute.

Society of Automotive Engineering Aerospace Recommend Practice (ARP) 1400B is considered the “gold standard” for piston aircraft oil filtration.

I've attached the data for the K&N HP-2004 filter. FYI the "Burst Pressure" is listed at 550psi, which exceeds the 500psi required by ARP. Interestingly, the Tempest filter became deformed at 496 psi (according to Champion's testing).

Here is a link to Champion's testing: https://www.championaerospace.com/wp...e-Analysis.pdf

Champion and Tempest filter to 25 micron, the K&N filters to 10 micron. You would think this would effect flow rate, but I'm not seeing specific flow rates for any of these filters. K&N claims their filters are "High Flow Rate" but don't back that claim up with any data that I can find.

YMMV.

My Challenger Oil Filters shipped from ASC today.

Found some
 

my local airport parts dealer has 2 tempest boxes in stock...he was only able to sell me 2, I tried to get 4 total (2) for anyone here in the forum but he wouldnt sell me more than I needed. He told me that he will only supply the local area airport.

BUT he also told me that his supplier said that Tempest filters supply issue should end and will be available back in stock next month. We will see.

My plane is going in for an annual next week, If the issue continues I will have my mechanic get 2 more filters, If he can...I should have 2 on hand for anyone here who desperately needs it.