91.205 compass requirement

On Sunday, April 17, 2016 at 3:43:07 PM UTC-7, Bill T wrote:
Unless the glider manual or TCDS lists the compass as required.

The question was "the magnetic compass requirement of FAR 91.205", not the POH. Clearly there is no such requirement for gliders.

Tom

On Sunday, April 17, 2016 at 10:45:50 AM UTC-7, wrote:
Does the ClearNav bearing display satisfy the magnetic compass requirement of FAR 91.205?

How does 91.205 apply to self-launching gliders? Or to touring motor gliders?

On Tuesday, April 19, 2016 at 12:10:43 AM UTC-7, wrote:

How does 91.205 apply to self-launching gliders? Or to touring motor gliders?

They are registered as gliders?
Jim

On Tuesday, April 19, 2016 at 12:10:43 AM UTC-7, wrote:

How does 91.205 apply to self-launching gliders? Or to touring motor gliders?

They are registered as gliders?
Jim

My motor glider is registered as a glider, Jim. But 91.205 does not use the word 'glider' it refers to 'Powered civil aircraft with standard category U.S. airworthiness certificates'. I have a self launcher, so would argue that although my glider is an aircraft, and is powered, the power is incidental to the flight, so its not a 'powered aircraft' as the FAA would define it. See also the FAA definition of a glider at the start of the FARs. I'm just guessing at the FAA's view here. But a touring motor glider might well be considered a 'powered aircraft' by the FAA, I'd guess, since its designed to cruise under power for a significant part of any flight.

On Tuesday, April 19, 2016 at 4:05:18 PM UTC-7, wrote:
On Tuesday, April 19, 2016 at 12:10:43 AM UTC-7, wrote:

How does 91.205 apply to self-launching gliders? Or to touring motor gliders?

They are registered as gliders?
Jim

My motor glider is registered as a glider, Jim. But 91.205 does not use the word 'glider' it refers to 'Powered civil aircraft with standard category U.S. airworthiness certificates'. I have a self launcher, so would argue that although my glider is an aircraft, and is powered, the power is incidental to the flight, so its not a 'powered aircraft' as the FAA would define it. See also the FAA definition of a glider at the start of the FARs. I'm just guessing at the FAA's view here. But a touring motor glider might well be considered a 'powered aircraft' by the FAA, I'd guess, since its designed to cruise under power for a significant part of any flight.

Why does this question keep coming up on r.a.s.. A motorglider of any type is a *glider*. There is no mystery here.

Is it certificated as Standard or Experimental?
Standard is outlined in 91.205, not experimental.

BillT

Why does this question keep coming up on r.a.s.. A motorglider of any type is a *glider*. There is no mystery here.

This conversation is about rule 91.205. There is no mention of 'glider' in that rule.

Originally Posted by

On Tuesday, April 19, 2016 at 12:10:43 AM UTC-7, wrote:

How does 91.205 apply to self-launching gliders? Or to touring motor gliders?

They are registered as gliders?
Jim

My motor glider is registered as a glider, Jim. But 91.205 does not use the word 'glider' it refers to 'Powered civil aircraft with standard category U.S. airworthiness certificates'. I have a self launcher, so would argue that although my glider is an aircraft, and is powered, the power is incidental to the flight, so its not a 'powered aircraft' as the FAA would define it. See also the FAA definition of a glider at the start of the FARs. I'm just guessing at the FAA's view here. But a touring motor glider might well be considered a 'powered aircraft' by the FAA, I'd guess, since its designed to cruise under power for a significant part of any flight.

Powered civil aircraft is a different category from gliders. All forms of motor gliders are just gliders that can self launch, tour or sustain themselves. 91.205 is not relevant to gliders, but the POH minimum equipment list is what the FAA will look at for standard category gliders with regards to compass fitment.

It could be argued that any system using a magnetic field sensor meets the definition of a magnetic compass with the proviso that it needs to be swung to match the local field disturbance from any metalwork in the vicinity. Maybe not gps systems? What you don't want to see is any reference to a liquid or "whiskey" compass.

On Tuesday, April 19, 2016 at 7:11:14 PM UTC-7, wrote:
Why does this question keep coming up on r.a.s.. A motorglider of any type is a *glider*. There is no mystery here.

This conversation is about rule 91.205. There is no mention of 'glider' in that rule.

Ah indeed you are right, and this exact point with 91.205 has come up on r.a.s. before, and as pointed out here in the past by others AC-21.17-2A precisely covers this.

http://www.faa.gov/documentlibrary/m...c_21.17-2a.pdf

Directly from that AC:

"Section 91.205 of the FAR. Powered gliders are considered to be powered aircraft for the purpose of complying with § 91.205 "

So to your point, except there is no flexibility here with no difference between a retracting engine self-launcher and touring motorglider etc. (and note as made very clear in this AC sustainers are also "powered gliders").

Ah indeed you are right, and this exact point with 91.205 has come up on r.a.s. before, and as pointed out here in the past by others AC-21.17-2A precisely covers this.

http://www.faa.gov/documentlibrary/m...c_21.17-2a.pdf

Directly from that AC:

"Section 91.205 of the FAR. Powered gliders are considered to be powered aircraft for the purpose of complying with § 91.205 "

So to your point, except there is no flexibility here with no difference between a retracting engine self-launcher and touring motorglider etc. (and note as made very clear in this AC sustainers are also "powered gliders").


Thanks Daryl, I now see this has been discussed on RAS before, as you said. I had not seen the past discussions. I should have done a search for past discussions of this topic. The AC you point out is clear for motorgliders on the 21.205 compass question we are discussing.

However I note that the AC preamble says "this material is neither mandatory or regulatory in nature, and does not constitute a regulation". I assume that means the AC's guidance on 21.205 is open to a different conclusion? I think its arguable that the AC's guidance on 21.205 is inconsistent with the FAA definition of a glider as "a heavier than air aircraft, that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and its free flight does not depend principally on an engine". This definition logically explains the otherwise-strange FAA view that a motorglider is a glider (even a touring motorglider). But following that definition, ie assuming motorglider free flight 'does not depend principally on an engine', a motorglider should more logically not be considered a 'powered aircraft' for 21.205.