TCAS RA's

[Brett Hull]

Are you required by regulation to follow an RA if you are operating under part 91? The only things I can find is 91.221, which basically says if you have it installed, you must turn it on. Also, 91.123, which says if you respond to an RA, notify ATC ASAP.

The boss and the other guy at work says you have to follow one if you get it. I say you don't. Who's buying beers?

Please don't turn this into a "why would you not want to" argument.

 

[CLCAP]

Not totally sure but our TCAS manual states that all RA's have to be followed (and even specifies a time limit). So at least on our airplane - you have to follow it. (Assuming that 91.221 requires you to operate your equipement in accordance with the manufacturers requirements)

 

[cvsfly]

Why should it matter if its Part 91 vs 135 vs 121 etc. If its there use it. If its there by regulation, then you probably can't MEL it on most flights. You are required to respond to the RA, but read in the manual what constitutes a response. Apparently ATC will no longer know ahead of time if you have TCAS installed - see revised AIM 5-1-7 ( T/ prefix no longer being used).

 

[tarp]

Ok, so you're probably right - there is no Part 91 regulation telling you to deviate from ATC instructions when you get an RA.

So now what?

Are you proposing that this is some great omission in the regs and must be rectified immediately?

Are you stating that because of the mid-air crash in Europe (Russian something and the other guy) where at least one airplane did not respond to the RA -- that something should be done?

So you win the beer. BUT, I'm always left with the feeling on this board that if people are thinking all these strange thoughts on the ground - what happens in the air. Let's say that you've proved your point beyond a shadow of a doubt. Let's say that 1% of the readers on the board are thinking - "yeah, if I'm Part 91, I may not have the authority to leave altitude and heading." And then one day, there they are in a TCAS equipped airplane and they get the RA. And they stop..... And then they think..... And then they go...."I wonder if I should do something?" And in the meantime......

Regulations can do nothing to regulate stupidity out of existence.

PS, according to my Ops Spec, on all company flights (121 or 91) if I get an RA, I'm required to take immediate action. But the Ops spec also tell me to do the same thing with my EGPWS. So I'm at FL310 on the East Coast and I get a GPWS "Terrain, terrain, pull up, pull up" - should I do it? See the previous paragraph.

 

[JayDub]

There has already been a test case for this scenario. There was an airline (I think United) in Chicago that hadn't filed TCAS but responded to an RA. They were busted (back when it very first was a requirement for part 121 ops).

Bottom line according to our FSDO: in part 91 ops you may or may not file TCAS. If you do, you'd better respond, then notify. If you don't file TCAS, ask permission to deviate from any altitude, especially for TCAS. After our dept. came to this realization, you better believe we filed with TCAS every time.

Respectfully,

JayDub

 

[JayDub]

Why should it matter if its Part 91 vs 135 vs 121 etc. If its there use it. If its there by regulation, then you probably can't MEL it on most flights. You are required to respond to the RA, but read in the manual what constitutes a response. Apparently ATC will no longer know ahead of time if you have TCAS installed - see revised AIM 5-1-7 ( T/ prefix no longer being used).

Check the other suffixes. TCAS is incorporated in all the other ones, so it was no longer necessary to have a prefix.

Respectfully,

JayDub

 

[cvsfly]

Check the other suffixes. TCAS is incorporated in all the other ones, so it was no longer necessary to have a prefix.

Respectfully,

JayDub

Which suffixes other than the one for RVSM (which assumes TCAS for the approval)?

 

[JayDub]

Serves me right for going by memory. I stand corrected.


JayDub

 

[Brett Hull]

Are you proposing that this is some great omission in the regs and must be rectified immediately?

Are you stating that because of the mid-air crash in Europe (Russian something and the other guy) where at least one airplane did not respond to the RA -- that something should be done?

Ummm....no.....

Just asking a question. Sorry if I got you steaming from the ears.

I guess no one read the last sentance in the original post.

 

[Snoopy58]

Brett,

I think you asked a much better question than the answers that you got. Here are two hypothetical scenarios that might happen under part 91 ops:

1. You're participating in a formation flight for the purposes of a photo shoot. Everything is thoroughly briefed and legal, but during the rejoin, you forgot to turn the TCAS from TA/RA to TA Only, and you get an RA. Both pilots involved have good visibility & situational awareness and there is no risk of a collision, but you have an RA. Are you *required* by part 91 to respond to it?

2. You're descending at the speed of heat, speedbrakes out, down to 10,000 to make a crossing restriction. You can see that you'll make it, but only just. ATC calls traffic to you level at 12 o'clock and 9000'. You report him in sight, and he likewise acknowledges you in sight (and was told that you would be leveling off one thousand feet above him). No other traffic nearby. Just before the autopilot begins its level-off, you get a "climb" RA. (Perhaps the traffic gets a "descend" RA.) You know that unless the autopilot botches the level-off, there will be no risk of a collision (and if it does, then you'll have time to disengage it & maneuver to avoid the collision). Does part 91 *require* that you intervene and respond to the RA?

In the part 121 FOM at my job, we do NOT have the option... we must respond to an RA. End of discussion. (Sure, you always have the *ability* not to respond, but you'd better have a good explanation, in terms of captain's emergency authority, avoiding a worse threat, whatever.) Of course, we don't do photo shoots, and we're told that the current version of our TCAS software won't flag cases like my (#2) until you MUST take action.

I think Brett's question is a valid one, and I'm not smart enough on Part 91 to answer it. Does Part 91 *require* a response to an RA in situations like those above? Or is it simply a really, really good idea 95% of the time, but technically the pilot's option?

 

[Brett Hull]

Thanks Snoopy!

and CLCAP for trying to answer.

Here's another situation: You're on an extended left base and the tower calls "traffic 12:00, three miles along the shoreline, a bugsmasher, 1500', smashing bugs in your direction." You call traffic in sight and continue on your base. As you're turning final, the TCAS gets it's panties in a wad and starts yelling at you to climb. Do you have to respond under part 91 (even though you SEE THE CONFLICT for the "if it's there use it" crowd)?

It's not about blatantly ignoring the frickin thing.

Sorry for the smart@ss comment, but you ask a simple question and jeez!

 

[cvsfly]

Read the TCAS manual. Read the AC on TCAS (don't have the #). Get training on TCAS. The regs don't tell you how to operate your equipment. TCAS is designed to keep you a certain distance from other traffic (with operating transponders). If you got a visual and are certain you can avoid the conflict don't sweat it (maybe the other guy will). I'd rather miss by a mile than by inches. If you are not going to use it as it is intended, remove it. either way don't depend on one source - your eyes (although the most important), TCAS, radio, etc. Fly safe.

 

[chperplt]

Of course, we don't do photo shoots, and we're told that the current version of our TCAS software won't flag cases like my (#2) until you MUST take action.

If I responded to every RA I got, my flightpath would look like my first attempt at straight and level..

Actually, the TCAS unit in my nice Beech 1900 isn't of the new variety. On a daily basis I get RAs. 99% of the time I am inbound to an airport that is a crossing point for another airports arrival. As mentioned above, the airplane is trying to meet the restriction, and to do so, they are coming down very fast. I'm level at 10, and they are busting a@@ down to 11, the RA will go off every time. If I have a visual on the traffic, I'm certainly not going to follow the decent command.

 

[xjcaptain]

I believe the real danger in not responding to a RA is THINKING that you have the traffic in sight, only to have the wrong traffic. Several high-profile mid-airs happened becuase of exactly this. Not to mention that if you don't comply, and the other does, it's another midair (I think it was DHL over Europe a year or so ago with that scenario). My OPINION is that if you are not going to comply, take it out because you are jeopardizing my safety and the safety of everybody you fly near. Have the professionalism to do it right, and do it right EVERY TIME. What is the advantage of not following the RA, trying to shave a second or two off the leg time? Might just as well ignore the GPWS, EGPWS or the TAWS systems also becuase I know CFIT can only happen to the other guy, right?