lmml 14/32
Posts: 2358
Joined: Tue Jan 30, 2001 2:27 am

Rvsm Certification

Fri Feb 15, 2002 3:18 am

How is an aircraft specially equipped for the recent European RVSM?
 
airplay
Posts: 3369
Joined: Sat Oct 25, 2003 1:58 am

RE: Rvsm Certification

Fri Feb 15, 2002 3:52 am

Essentially you need accurate air data computers and an autopilot that can maintain altitude accurately.

On the whole, RVSM certification is a fairly complex undertaking involving lots of engineering and flight testing.
 
lmml 14/32
Posts: 2358
Joined: Tue Jan 30, 2001 2:27 am

RE: Rvsm Certification

Fri Feb 15, 2002 4:47 am

Is TCAS a compulsory item for RVSM? I suppose so.
 
747Teach
Posts: 176
Joined: Wed Nov 29, 2000 3:05 am

RE: Rvsm Certification

Fri Feb 15, 2002 5:43 am

LMML 14/32: I will try to give you a short rundown on most of the required equipment for RVSM operations. 2 independent altitude measurement systems, each with a mean system error of less than 80 ft in normal operation, cross-coupled static sources, automatic altitude reporting, automatic altitude control with an accuracy of + or - 65 feet, 1 altitude alerting system, reference signals for autopilot and alerting systems, static source error correction (if needed), 1 altitude reporting transponder, 1 automatic altitude control system which is referenced to pressure altitude, and several other items of equipment, such as auto throttle control, that may vary by operator and aircraft type.
The process begins by measuring the fuselage around the pitot probes for "waviness." A tool is installed, and the skin is measured. These figures are submitted to the aircraft manufacturer which runs the numbers to calculate an average flatness for the area. If the skin is not flat to within certain limits, the skin around the pitot probes will need to be shimmed until the criteria is met. Then, in the case of some 747's for example, new pitot probes with a nickel-plated 10" strut will replace the older model 4" strut. The area around the pitot probes is defined by a striped line, inside which no unaccounted for dents are allowed, and any dents that do occur inside that area will need to be reported and repaired. It is very likely that the altimeters will need to be replaced with much more accurate units. Some of the newer altimeters will incorporate other features required for RVSM operation, such as altitude reporting, or a selectable mode that gives the altimeter reading in metric units. The entire pitot-static system must be carefully calibrated, and the air data computers and autopilot system must meet greater accuracy requirements.
Then other systems, such as the transponder altitude reporting feature must be verified to be within certain accuracy limits. The purpose of all these requirements is to guarantee, as much as possible, that the aircraft is actually at its assigned altitude. Obviously, that is a critical requirement in airspace with a separation of 1000 ft vertically.
If you check the picture at
Click for large version
Click here for full size photo!

Photo © Jonathan Icasas

you will clearly see the markings around the pitot area on this 747.
This information is excerpted from the 747 maintenance manuals, chapter 22 for autopilot, and 34 for the air data systems. Also, a number of supplement pages that accompany the basic manuals. Not all operators will need to add or change their equipment, depending on how their particular equipment was purchased. I believe the numbers are accurate, but of course, are revised continually. Hope this helps, regards,

 
Guest

RE: Rvsm Certification

Fri Feb 15, 2002 6:26 am

Aircraft systems requirement for RVSM, from the FAA 91-RVSM document, can be found on the following website --for everything you ever want to know about RVSM (and more):
http://www.faa.gov/ats/ato/rvsm_documentation.htm

To answer LMML, TCAS is not required for RVSM. However, if you have TCAS in the airplane, you need to have training and demonstrate TCAS know-how. For Europe, since all aircraft with MTOW greater than 33,000 lbs OR with more than 30 pax seats have to be equipped with TCAS, change 7, virtually all aircraft that fly in RVSM airspace would have TCAS due to their weights.

Regards,
Nut
 
lmml 14/32
Posts: 2358
Joined: Tue Jan 30, 2001 2:27 am

RE: Rvsm Certification

Fri Feb 15, 2002 7:28 am

Thank you both for the very detailed information and links.
747Teach: You mentioned Auto Throttle. Is that a requirement too?
 
airplay
Posts: 3369
Joined: Sat Oct 25, 2003 1:58 am

RE: Rvsm Certification

Fri Feb 15, 2002 8:38 am

Lots of words to say essentially:

"you need accurate air data computers and an autopilot that can maintain altitude accurately."

 Smile




 
Rick767
Posts: 2613
Joined: Sun Jan 30, 2000 8:11 pm

RE: Rvsm Certification

Mon Feb 18, 2002 8:16 am

Autothrottle is not a requirement.
I used to love the smell of Jet-A in the morning...
 
747Teach
Posts: 176
Joined: Wed Nov 29, 2000 3:05 am

RE: Rvsm Certification

Tue Feb 19, 2002 3:20 am

LMML14/32: If you read the FAA9-RVSM document that MD11nut refers to, you will see in the document GC59 Rev. 1, a comment that "the FOEB Chairman may need to address some specific aircraft systems independently," and goes on to mention operational limitations on the classic 747 that may "mandate the use of autothrottles to preclude unacceptable mach excursions which can induce altimetry system errors." So as I said, some system requirements may vary by aircraft type and operator. I don't believe 747 aircraft with the SPZ-1 autopilot are required to have autothrottle working and engaged in order to fly in RVSM airspace, but I can't say about any other make of autopilot, or "automatic altitude control system." And of course, there may be other types of equipment that may or may not be required on other kinds of aircraft. Each operator may petition for relief from some requirements depending on their experience with their own equipment. Regards,

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