Accumulator

[mshac]

Originally Posted by JMH

Thread revival...
Whats the impact in the type certification for removing the accumulators on an O-2A. Is it a legal mod from the manufacturer POV?
Thanks!

I've read that most O2 owners have removed the accumulators, in fact you'd likely be hard-pressed to find one actively flying that still has them.

Based on this, I don't think there's any issue removing them, any more than there would be an issue removing boots from a plane that came with them. Remove them, issue a corrected W&B, note it it the airframe log and you're golden.

EDIT: I'm a big fan of accumulators on multi engine trainers, where you feather a prop almost every flight. They make in-flight engine restarts 10x smoother. But on a non-training aircraft, where the only time you feather a prop is because you have to, I don't see the value. You lose the weight of a suitcase for something you really don't need. Furthermore, they are just like a strut - if you don't keep them serviced with nitrogen, they won't work.

[cessnadriver]

mshac. Since the accumulators are optional, and as long as the WT&BAL is updated there is no problem with removing them.
Bill Story
'65 C337 Owner, pilot and A&P

[cfc1234]

Is there documentation allowing their removal? What says they are optional if it came with them installed?

[JMH]

I believe it is implied that it is optional, since some were built without them. We are having an A&P look at it, add it to the Mx logs, and probably put a "notice" in the cockpit that they are not installed. Makes sense to not have them, just trying to do it the right way and stay within the certification

[skymstr02]

Look in the type certificate data sheet, if its required it will be listed here. If its not listed, you may remove them. Look for the weight and arm in your T.O. 1L-2A-5 Technical Manual. Item number D-1 for the rear accumulator, 5 lbs at station 207, and 5 lbs at sta 35 for the front accumulator, item A-1.

Removing the accumulators is no different from removing the ARN-83 Receiver or the APX 64 receiver transmitter.

[JimC]

Originally Posted by skymstr02

Look in the type certificate data sheet, if its required it will be listed here. If its not listed, you may remove them.

There are many things not listed in the TCDS that you are not allowed to remove on some airplanes, but are allowed to remove on others - doors, for example.

There can also be things listed in a TCDS that you *are* allowed to remove. For example, the TCDS for a Cessna 340 lists 6 seats, but the equipment list in the POH makes it clear that only one is required for flight.

Cessna didn't start providing equipment lists until the mid 70's. You won't find them in the old "Owner's Manuals." They don't start showing up until you have a "Pilot's Operating Handbook."

[skymstr02]

Jim C, we're not talking civilian 337's here, we're talking O-2A's, different animal. The M-337B has a different paragraph in the TCDS, same as the 337G or H models. The O-2's have a document called the dash 5 that I referred to earlier in this thread. It allows the removal of certain installed items and still allows the airplane to perform its mission. For example, it allows the removal of wing weapon pylons, it allows the removal of M-16 rifles. It does not allow the removal of tires, brakes and other required items.
There is no pilots operating handbook or equipment list like you will find for a 340 for the O-2A or B. If you go to the FAA Master MMEL list, you can even operate under certain conditions fly legally without meeting the minimum equipment for basic VFR under parts 23 or 91. For instance, you could legally fly without operating fuel quantity gauges or magnetic compass.
If you look at the TCDS for a 337D, you will notice that prop spinners and bulkheads are required, but for the O-2A's built at the same time, they are not.