View Full Version : TCAS Inoperative RVSM

Jimmy Hoffa Rocks
2nd Aug 2011, 18:49
if one has TCAS inoperative on the A 320

The MEL says no P-RNAV and not to be flown in RVSM Airspace.

This seems reasonable but cant find where it is written TCAS mandatory in RVSM and for P-RNAV OPS apart from the MEL

Eurocontrol does allow one to fly in RVSM with no TCAS ? or not ?
As dont recall seeing TCAS as required RVSM item

Would you refuse to accept a aircraft with no TCAS in certain airports ?

Could someone please shed some light on this and pass a link to the written Eurocontrol or relevant links.

Thanks in advance

2nd Aug 2011, 19:06
RVSM indeed does not require TCAS, however if you have TCAS you need a certain version number. However within the ECAC states carriage of TCAS is mandatory, up to 10 days of inoperative TCAS is possible except in germany where it is 3 days (applicable to all aircraft including overflights). See also here (http://www.eurocontrol.int/msa/public/standard_page/ACAS_Equipage_Requirements.html) for eurocontrol infos.

2nd Aug 2011, 21:32
If YOUR approved MEL says TCAS is required in RVSM airspace, then YOUR MEL overrides any permissiveness of an individual government. If you take the aircraft, then plan to stay below RVSM airspace and to not use any P-RNAV routes or procedures.

3rd Aug 2011, 01:45
I seemed to remember certain FIRs requires TCAS to be operative eg. India..( i think...)

Can someone plz comment on the P-Rnav requirement? TCAS required?

Many thanks.

3rd Aug 2011, 07:00
pwned is correct....

Fly safe,


3rd Aug 2011, 13:01
Happened to me last month. After take off TCAS stopped working. We checked RVSM requirements. No TCAS needed (as long one transponder is servicable).

However, in our MEL was stated that prior to flight, approval must be obtained from all overflying ATC authorities and we can not depart from hour home base, but this is Company policy.

As far as i know, TCAS has nothing to do with RNAV.

3rd Aug 2011, 16:17
RVSM.....not RNAV

Fly safe,


3rd Aug 2011, 18:40
The OP also mentioned that P-RNAV ops are disallowed by the MEL in question with TCAS inop. Seems a bit overly restrictive to me too.

Too Few Stripes
4th Aug 2011, 19:33
TCAS is not a requirement for RVSM airspace in general, however it is required in European RVSM airspace. If it is unserviceable then you can fly in European RVSM airspace for 10 days without it, with the exception of Germany where the exemption is 3 days. All of this information is availabale on the Eurocontrol website.

CJ Driver
4th Aug 2011, 21:25
Too Few Stripes - what makes you say that TCAS is required in RVSM airspace? As I understand it, TCAS is an aircraft requirement (based on MTOW and passenger seats), and the airspace flown is irrelevant.

I speak as someone who routinely flies in RVSM airspace without TCAS.

Too Few Stripes
4th Aug 2011, 23:19
The following is a direct cut and paste from EUROCONTROL - ACAS II Equipage Requirements (http://www.eurocontrol.int/msa/public/standard_page/ACAS_Equipage_Requirements.html)

Minimum Equipment List (MEL) exemptions

Flying with an inoperative ACAS II is permitted, including within RVSM airspace, provided it is done in accordance with the applicable Minimum Equipment List (MEL).

The MEL for TCAS II throughout Europe is Class C - 10 days (excluding the day of discovery). Operation under the terms of the EASA-OPS 1 TCAS II MEL has been agreed and accepted by the ECAC Member States. JAA TGL 26 (which is still applicable) states that TCAS II "may be inoperative provided the system is deactivated and secured, and repairs or replacements are carried out within 10 calendar days. Note: Local Authorities may impose a more restrictive rectification interval days."

Additional MEL requirements concerning partial failures are also listed in the TGL 26. Note: the actual MEL period applicable to an aircraft is set by the national authority of the aircraft operator, but if longer than Class C it would cause operational issues for flights in European airspace.

However, one State in Europe applies a more restrictive requirement: in German airspace the time period during which TCAS II may be inoperative is reduced to 3 days (refer to German AIP GEN 1.5 para. 5). This applies to all aircraft.

Also, you will note from my earlier post that I said TCAS/ACAS is not a requirement of RVSM airspace in general, but it is in Europe .

Further info can be found here - EUROCONTROL Navigation Domain - Pilots (http://www.ecacnav.com/content.asp?PageID=77#Q1)

Hopefully that all makes sense and gives a black and white answer.

5th Aug 2011, 00:42
Remember that the MEL applies for Dispatch. If a system fails inflight, then the appropriate non-normal procedures are applicable.

While the MEL may have some good information to use in case of an inflight failure, its restrictions may not necessarily apply...

For the OP, if the MEL says no P-RNAV or RVSM, then you cannot Dispatch with any flight plan that requires them. However, if the TCAS fails in flight, then you may proceed on your flight plan if the non-normal procedures do not prohibit it.

CJ Driver
7th Aug 2011, 17:49
Two Stripes - I read your post, and then I read it again to check I wasn't missing something. It's from the ACAS page at Eurocontrol. There is an "Urban Myth" that many people believe that ACAS is somehow part of RVSM equipment. Thus the article you quoted - which is about MEL relief for inoperative ACAS - even includes the comment "including in RVSM airspace" to make clear that you don't need ACAS to fly in RVSM airspace.

I wil grant you that the RVSM FAQ article in the second link you quoted is confusing. The question P1 is "Do I need TCAS to fly in RVSM airspace". The answer they give is "No". They then confuse the issue completely by saying that you must have ACAS in Europe if your aircraft is over 5700 kg and/or has more than 19 seats. But this is regardless of which airspace, RVSM or non-RVSM, you are flying in. That rule has nothing to do with RVSM. I don't know why they put it there. Perhaps that is where some of the "Urban Myth" comes from.

So, just to clear up:

In Europe, if your aircraft has turbine engines and is over 5700 kg or has more than 19 passenger seats, then it must have ACAS for ANY airspace. If your aircraft is less than 5700kg and has less than 20 passenger seats, you do not need ACAS - in ANY airspace. There is NO regulatory connection between RVSM airspace and ACAS carriage. *

Thus, for example, most light jets and smaller turboprops that are flying in RVSM airspace (such as smaller Citations) do not have ACAS.

* OK, for the pedants amongst you, there IS a regulatory link between RVSM and ACAS. If you have ACAS and want to fly in RVSM airspace, there are constraints about the software version in your ACAS computer - you need to have an RVSM-aware software build. But, that really wasn't the original discussion, so I have relegated it to a footnote. :hmm:

6th Apr 2013, 11:25
In India, when flying within any of the 4 FIRs, TCAS II is a compulsory along with the 2 primary altimeters (1 altitude reporting and 1 altitude alerting).

Follow up question:
What is the pilot call out for an equipment failure in RVSM airspace? - Is it just simply "UNABLE RVSM DUE TO EQUIPMENT"

I'm aware that when deviation is required due to weather it is " PAN-PAN (3 times) WEATHER DEVIATION REQUIRED."

What does one do in the event of an equipment failure?