It does indeed.

It makes it very clear that there is a path for non-certified aircraft to legally fly in RVSM airspace under section 9.

Understood. I agree, actually. But the text of the regulation is not prescriptive, it is performative. As long as you perform as required… you aren’t in violation, apparently.

That said, the FAA has clearly produced additional documents that say they strongly recommend engineering solutions. The one Ryan just posted is one example. They hint at exactly what you said, enforcement would be with 20/20 hindsight if monitoring shows you are out of bounds.

But neither do those documents explicitly state the regulation requires a certified solution. It is a curious absence if that is what the regulation really required. Jim’s description of doing an RVSM test flight and visiting ends of the airspeed envelope and then collecting the naarmo data sounds like it is someone who gave consideration to the issues and used the FAA’s own test to check the performance. Even a certified solution needs to do that.

It does indeed.

It makes it very clear that there is a path for non-certified aircraft to legally fly in RVSM airspace under section 9.

I have a very serious question- why is that not a reasonable path?

I can pay an engineering firm to outfit my airplane with test equipment, set up a trailing cone, and go do test flights to measure my ASE. I’ll get instant results.

Or I can go do the same flights in RVSM airspace without the test equipment, and then wait for NAARMO to tell me my ASE.

The first one costs money, the second one costs a lot of time waiting for results.

If I don’t meet the ASE standards using the first method, the engineering team will help me find a solution.

If I don’t meet the ASE standards using the second method, I’m SOL. There is no reasonable path to compliance without going back to method one.

When the stated purpose of the rule is to reduce burdens and costs, why is trying the second method “not the way?” What am I missing?

My reading is not that you "need" an engineering analysis, rather that if you fly in RVSM airspace and DON'T meet the standard, the FAA might come after you and want to see that you took steps beforehand to have confidence that you would. Engineering analysis would be one way of doing that, and it's one the FAA is familiar and comfortable with, but they are NOT saying it's the only way.

I have a very serious question- why is that not a reasonable path?

I see "and" in the below sentence. Sure sounds like all 3 need to be done.

"This evaluation involves engineering analysis, flight-testing, and measurement of system level performance. "

I have a very serious question- why is that not a reasonable path?

I can pay an engineering firm to outfit my airplane with test equipment, set up a trailing cone, and go do test flights to measure my ASE. I’ll get instant results.

Or I can go do the same flights in RVSM airspace without the test equipment, and then wait for NAARMO to tell me my ASE.

The first one costs money, the second one costs a lot of time waiting for results.

If I don’t meet the ASE standards using the first method, the engineering team will help me find a solution.

If I don’t meet the ASE standards using the second method, I’m SOL. There is no reasonable path to compliance without going back to method one.

When the stated purpose of the rule is to reduce burdens and costs, why is trying the second method “not the way?” What am I missing?

The only opinion that the letter offers is that they “recommend” path one. They do not require it.

BTW, who wrote that letter? It’s on an FAA website but it doesn’t have a document number, revision number, operational division or an author. Is it official policy?

Absolutely.

If you’re having trouble getting permission to enter RVSM airspace while negative RVSM, come down to the southwest. We have tons of empty airspace.

It is worth noting that the full blown certification effort would ultimately require a test flight in RVSM airspace while negative RVSM. So assuming Jim (for example) declared his intention and properly coordinated with ATC, I don’t see that as a big hang up.

I just did something I can't recommend to anyone: I called the FAA and volunteered my name, tail number, RVSM certification status, equipment status and flying habits - and then I asked if I was doing anything wrong. It's DUMB and you should never do that, but I decided to take one for the team.

I called John Warburton, head of the Separation Standards Analysis Branch and peppered him with questions. It was a thorough, informative and productive call. He's retiring next week, so if you call again you may not get him. Yes, it was a little scary, because he knew who I was immediately. He mentioned that they hadn't replied to my email because they were looking into the international flights I made. Yes, they were looking at all my flights before they replied - I guess I didn't need to tell him how I was operating. Yes, I dropped to FL270 before entering Canada. I should be getting the letter giving me a thumbs up in writing today or tomorrow.

There are 3 things that matter when operating under Section 9:

Performance,

Performance,

and Performance.


Here's my Appendix G, Section 9 FAQ. I may be able to answer other questions you have, but remember that this is internet advice. It's worth what you paid for it.

Do I have to have a certified RVSM system?
No, you do not. Full stop. Period. The separations branch and flight safety division wanted that, but it's not how it got written. Many of the advisory letters reflect that - they didn't get what they wanted in the rule, so they continue to push for certification. RVSM certification is recommended, not required. Engineering analysis is recommended, not required.

What equipment can I use?
As long as your equipment does not prohibit RVSM, they don't care what equipment you have installed. They don't care what your SSEC numbers are. They don't care how you got there. They just care that your equipment meets the performance standards in Section 9, especially the ASE performance requirements.

How do you know your ASE performance if you choose to go section 9 without engineering analysis?
You test it using the method I described, and then you keep flying after you pass. They monitor 40,000 flights every day. They are monitoring far more planes than just the planes on the Section 9 list. If you fall out of limits, they will tell you. They will NOT tell you if your ASE is out of compliance if you're not in RVSM airspace. Successful monitoring inside RVSM airspace is required once every two years, and it's up to you to verify that. If you exceed the two year window you have to go back and explicitly do the monitoring test flights again. This year they flagged about 150 flights for ASE out of compliance with RVSM. Some of those were the same plane more than once.

What happens if you get flagged?
It is NOT considered a violation if you have a recent previous test flight that shows acceptable ASE performance. As he put it, "Under Section 9, you can't know you're out of compliance until we tell you, so we don't violate for that." They will contact you and let you know that your ASE is no longer compliant with RVSM. If you fly RVSM again after being notified that you are non-compliant without addressing your problems, you are in violation - duh! It does NOT automatically mean that a proctological examination of your testing procedures is coming. That certainly may be possible, but it's not policy.

How do I know if I'm near the edge of ASE compliance?
You don't. They'd like to have a green, yellow, red system where yellow means you're close to the edge and may want to look into it, but their database doesn't support that. They were also hoping to get ASE blended into the PAPR but the PAPR can't support that.

What happens if my ASE shows errors because of GPS interference?
Then everyone around you will also show ASE errors because of GPS interference and nobody gets flagged. It's one of the unexpected side benefits of ASE monitoring - they can see GPS interference areas easily. "In data it looks like a school of fish swerving to avoid a shark."

Why in the hell did you call the FAA and tell them your name?
Because I'm not very bright. But y'all owe me a beer for doing this.

Jim,

Thanks for taking one for the team. Well done!

Also very nice report of what you found.

Brilliant! Thanks for your effort.

Wow, that is a surprising answer. Do they plan to clarify this in writing?