I see that is lots of legacy Citations with steam gauges and some Conquests.

Mike C.

I see that is lots of legacy Citations with steam gauges and some Conquests.

Mike C.

[/quote]
It's not a mechanical altimeter. If you see that on a legacy RVSM Citation then it will be the Honeywell BA-141 altimeter indicator, which is just a servo'd display from the Air Data Computer. Because the ADC RVSM upgrades were expensive, you see a lot with dual IS&S ADDU (air data display unit, which has the adc built in), dual Ametek (also has adc built in), or Honeywell on the left side and Ametek on the right side.

All the RVSM 441s I've seen have dual Ametek or Thommen.

If you see any of these with a mechanical altimeter on either side (as primary, not backup), then it is not RVSM certified.[/quote]

I would be suprised if Terry is not right.

Back before RVSM came out and the Co-Pilot's altimeter was uncorrected there was always a large difference between the Pilot's and Co-Pilot's altimeters on the airplanes I flew in what is now RVSM airspace.

Our (customer) RVSM 441 has the Meggitt system on the left side, and the Honeywell AM-250 on the right side. There is a standby altimeter, a United 5934PA.

Jason

Hmm, upon further review, it isn't clear the ASE requirement is an *equipment* requirement, but an *operational* requirement:

An operator is authorized to conduct flight in airspace in which RVSM is applied provided:

(a) The aircraft is equipped with the following:

[2 altimeters, AP +/- 130 ft, alerter +/- 300 ft, 1090ES ADS-B]

(b) The altimetry system error (ASE) of the aircraft does not exceed 200 feet when operating in RVSM airspace.

My reading of this suggests that you meet the equipment list in section (a), then you can operate in RVSM until ATC says your ASE is too large and kicks you out under section (b). In other words, (b) is a real time, in the moment test conducted by the FAA systems, no need to demonstrate or prove PRIOR to operating in RVSM.

In other words, it appears there is no equipment criteria for ASE in section (a), thus no need to prove you have achieved it. Just go operate in RVSM and see what happens.

Mike C.

I highly doubt that the FAA would be happy with your "Just go operate in RVSM and see what happens" attitude. The main change with the new regulation is you no longer need a LOA. The FAA does need to come out with a better description of how to meet the RVSM requirements.

It isn't an "attitude".

It is written in the language.

You need less than 200 ft ASE WHEN OPERATING in RVSM airspace.

No ASE requirement is in the equipment checklist.

Mike C.

Note this language in the FAA rule front matter:

Revise Section 2 (Aircraft Approval) and Section 3 (Operator Authorization) to recognize aircraft operators may either use the current aircraft approval process specified in Section 2 and the operator authorization process specified in Section 3, or the authorization process in new Section 9 for aircraft equipped with qualified ADS-B Out systems to obtain authorization to conduct RVSM operations.

Very clearly states the AIRCRAFT approval changes when using section 9.

Mike C.

While I kind of hope this is the case for my ability to fly in the low RVSM altitudes, it might make flight planning a little tricky - I flight plan a trip at FL310 for fuel burn and winds aloft (maybe other weather), but somewhere along the way ATC says “today your ASE is too large so you have to descend to FL270”. Could it vary day to day depending on actual barometric conditions and whatever minor error exists in ones altimetry system?

Seems like there’s some uncertainty about what one is able to do from flight to flight.

It should not vary with baro conditions, but it can vary day to day with temperature, speed, etc.

FAA papers show any given serial number can vary. Here is one serial number 737:

A lot of the noise here can be in the FAA measurement. Also, the mode C data is only 100 ft increments, so there will always be 100 ft noise in the data.

Note that a 737 experiences a wide range of altitudes, FL290 to FL410, and your MU2 would only use 3, FL290, FL300, and FL310. So you have a much narrower range of possible variance and thus more likely to be consistent.

Mike C.

How would this work in practice?

Do I request (say) FL300, and somehow before I get there atc says “sorry, your ASE is too large today, maintain FL280”? Or do I ask atc “is my altimeter error acceptable today so that I can go to FL300” before I ask for such an altitude? What equipment suffix would I file? Can I file FL300 if I don’t know whether with today’s conditions I will be able to get it? If I cross a center boundary might their equipment be just different enough that one would allow me but one would boot me out of RVSM space?

While I like the theory, and I can see the change in the equipment rule language you are pointing out, it sure could use some FAA clarification to become practical.

I’d love for someone (else) to be the guinea pig.

In theory, check off the (a) equipment list, file for FL300, go fly, and let ATC tell you if you are off under (b).


That's a great question. I think you would file RVSM equipped since section 9 is part of the RVSM rule, and you meet it.

In foreign airspace, however, you wouldn't be RVSM unless you meet section 2/3 requirements, so your equipment letter changes based on jurisdiction.


Possible in theory.

I think in practice, your ASE would be monitored over some period of time (more than one flight) and a go/no go bit is set for your airplane. Perhaps this is already being done even though you are not going into RVSM airspace yet. So I assume there is a tolerance on any given flight that if you exceed, you are out, and that's probably +/- 300 ft, and then there's a long term measurement built over many flights and is tighter.

This kind of already happens with mode C. We've all heard the "stop mode C" when a plane's mode C varies too much from its altitude reported by radio. Sounds like this would be similar.


Definitely could use some guidance, but the guidance isn't rule when it comes.

This has me wondering what an STC to raise my ceiling would cost. With my engines, FL290+ is definitely possible.

Mike C.

Can someone ungovernment this language for me:

"(4) A TCAS II that meets TSO C-119b (Version 7.0), or a later version, if equipped with TCAS II, unless otherwise authorized by the Administrator."

Does that mean IF you have TCAS II it has to be version 7.0 or newer, but if you don't even have TCAS II then the whole part 4 doesn't apply to you? I only have TCAS I.

Thanks,

Chip-

Correct.

Not sure why that part exists in this change since it doesn't seem to have anything to do with altitude.

Mike C.

It doesn't apply to you. The versions of TCAS II before version 7.0 had some resolution advisory solutions that would cause false alerts in RVSM airspace.