TCAS TAonly in high altitude cruise

[mgTF]

Hi,
my company soon will add minor changes to the existing SOP, one of this changes is to set the TCAS on TAonly during high altitude cruise, because of the net ceiling of the plane doesn't allow any eventual CLIMB RESOLUTION.

They said that on the airbus fleet it is a manufacturer standard operation, therefore with the aim of improve standardization on the whole airline we should perform this practice on any other jet.

what do you think?
I'm gonna say that this is totally unsafe,
what if you are cruising at fl380, converging traffic both on TA only no one will ever get any resolution; but probably both pilot will think that at least the other aircraft will get a ANY RESOLUTIVE command.
if both are in RA one for sure will get a descent and will start to descent and the other will get a climb, then even if the performances are really bad, for sure it will increase the clearance in beetween!!

[bucket_and_spade]

Hi,

Think there's a thread on TCAS v. aircraft performance somewhere on these forums - remember reading it a while back...

B&S

[moscho999]

For the 737NG the following applies:
When cruising at or near 41,000 feet (Max.ALT according Limitations), the TCAS may issue a Climb RA. The flight crew should comply even if the maneuver causes a minor and brief climb above the maximum operational altitude as this allows TCAS to advise the best coordinated resolution maneuver. The airplane is still capable of maintaining a 2500 feet per minute climb rate at an altitude greater than the maximum operational altitude.

Greetings

[Daysleeper]

mgTFThat is a crazy and dangerous procedure and should not be in place on any of your fleet regardless of manufacturer.


In a co-ordinated TCAS RA - YOU may be the one getting the DESCEND DESCEND command , which you wont get if your on TA only, secondly if you get a climb RA at the max certificated level of your aircraft you will still have a (small) maneuver margin ... but its still better than hitting the other aircraft, even 50 ft will give you some separation (TCAS resolves in 25ft increments)

Look at TCAS Update (http://www.copac.es/direcciones/Seguridad/seguridad-ATC/BOLETIN%20ACAS/Boletín%20ACAS%20Nº1%20%20Follow%20the%20RA!.pdf) event 5 and 6

In conclusion.....if there is some doubt of the ability to respond to a “Climb” RA, at least remain level, do not descend.

[Port Strobe]

Does a change to SOPs of this nature require approval from the NAA the AOC is held with? If so wouldn't they see the potential for a precedent being set and the whole world flying around on TA only?

[zerozero]

Operating in RVSM airspace, nobody needs to be climbing thousands of feet to avoid a collision--you just might find yourself with another conflict!

A climb or descent of 500' is sufficient. Any jet aircraft should have enough inertia (if not power) to manage that.

[mgTF]

I'm totally agree with you, and what if all companies adopt this procedure...

is there any airbus pilot that can support it as a standard procedure?

[Fly3]

This procedure is most definately not Airbus practice and is a recipe for disaster. It is difficult to believe that anyone could be so stupid to as to implement such a thing. Even if you are cruising at high altitude at heavy weights you will always have speed in hand to climb in event of an RA and exceeding the max alt by a few hundred feet is not a problem.

[Graybeard]

As part of TCAS certification, there is a strapping option for max altitude at which the plane can achieve 1500 fpm climb for 300 feet. This is based on data from the airframe manufacturer.

Above that altitude, the TCAS will give only Maintain or Descend commands, and thus keep everybody separated.

There are subsets of that, like the 747-100 being strapped to never give a Climb command with flaps beyond a certain setting, (like 7 1/2 degrees, IIRC.)

GB