Author Topic: Landing Gear oleo servicing 391B  (Read 91 times)

Bill Miller

Landing Gear oleo servicing 391B
« on: December 05, 2017, 11:28:57 AM »
My POH is missing these critical pages for servicing the landing gear struts (see below: poh ref to pp 42 and 43A which are missing)s. We seem to have a persistent droop on the right main gear and I am looking for an A&P in Texas near Houston who can advise me or show us the technique.
Thanks
Bill

OPERATION AND MAINTENANCE MANUAL HELIO COURIER MODEL H-391 B
Page 40 Landing gear:

"1. Main and TaiI shock systems
- Diagrams provide sufficient servicing information to maintain the main tail wheel landing gear systems.
See page 42 and 43A"

Interesting the PDF posted on line is missing these same pages... anybody? else
http://airborneattitude.com/pdfs/H391b_POH_part2.PDF

Bill Miller

Re: Landing Gear oleo servicing 391B
« Reply #1 on: December 05, 2017, 11:44:40 AM »
ON FURTHER SEARCH THAT WEBSITE PROVIDES THE FOLD OUT DIAGRAM HERE FOR THE" MISSING PAGES"
http://airborneattitude.com/pdfs/H391b_POH_part4.PDF

It says to inflate main shock to 3.88 to 4.00 inches " to top of cylinder, but we don't know what is the normal expected pressure range for the high pressure nitrogen. Does anyone have guidance on the expected pressure to reach 4.00 or perhaps this comes from experience? Unless I am missing something the " sufficient servicing information" does not appear on this version of page 42 (page 43A is for the tailwheel)
Thanks
Bill

jmetzler

Re: Landing Gear oleo servicing 391B
« Reply #2 on: December 05, 2017, 06:21:40 PM »
Hi Bill,

I checked the military manual to see if it had more information on servicing and it really doesn't. What I do is put the main gear on a set of grease plates so the gear can move easier. With the struts serviced with hydraulic fluid, put nitrogen in while having someone gently rock the aircraft at the wing tip. It will take almost 1000 psi of nitrogen to raise the aircraft. If you over inflate, you can open the valve a bit and let some nitrogen out but be careful as it happens fast! 3.88" to 4.00" is a good reference point but more importantly is is having the wing tips at the same height. I either measure them to the ground or since I'm short, I add three fingers to my height.  After many years of operation and probably a few "adjustments" to the cabin structure, the 3.88-4.00" might or might not work. The tail strut takes a lot less pressure. Jim