Crew ignored TCAS RA [Archive]

RAT 5

8th Nov 2016, 15:50

Golf: Is an RA indeed an advisory? I know what its title is, and similar to some manufacturer's confusing labelling of MCT that is not meant to be unlimited continuous, (see a tech log topic) the use of Resolution Advisory as a title, when in fact it is a Command to act, can lead the Oxford dictionary police to cry foul.
Notwithstanding it may be the wrong a/c you can see, you do not know what TCAS has commanded that other a/c to do. By not following your command you might then become the target for the avoidance manoeuvre of the other a/c and then require TCAS to 2nd guess and issue further commands. If you ignored those, things will be going south very fast. The closing speeds are a blink of an eye and the inertia involved could prevent an avoiding manoeuvre, even if visual. Remember, pulling 4g or turning with 4g will most likely put the threat traffic blind to you, and likewise them to you if they rack it around. Equally a -3g bunt would generate some customer complaints & much paperwork.
Question is, in this day and age of the ever growing world of 3 letter abbreviations, TEM is quite the new fashion. 'If there is doubt there is no doubt' was drummed into me from day 1. It still holds true; so why risk it?

aterpster

8th Nov 2016, 16:15

The FAA's position:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_120-55C_CHG_1.pdf

oxenos

8th Nov 2016, 16:28

The nub of the FAA position is:-

"(2) When an RA occurs, the PF should respond immediately by directing attention to RA
displays and maneuver as indicated, unless doing so would jeopardize the safe operation of the
flight or the flightcrew can ensure separation with the help of definitive visual acquisition of the
aircraft causing the RA. By not responding to an RA, the flightcrew effectively takes
responsibility for achieving safe separation. In so choosing, consider the following cautions:
(a) The traffic may also be equipped with TCAS and it may maneuver in response to
an RA coordinated with your own TCAS.
(b) The traffic acquired visually may not be the same traffic causing the RA.
(c) Visual perception of the encounter may be misleading. Unless it is unequivocally
clear that the target acquired visually is the one generating the RA and there are no complicating
circumstances, the pilot’s instinctive reaction should always be to respond to RAs in the
direction and to the degree displayed. "

If you don't like that, why not pop the circuit breakers and get rid of it? While you are there, you might as well pop the ones for the GPWS and the fire warning system and the stall warning and the config warning and the cabin alt warning and all those other things which make an annoying noise. So much nicer with a quiet fl;ight deck.

Capt Ecureuil

8th Nov 2016, 17:10

I do hope those indicating that following a RA is optional aren't pilots, worries the #@*t$ out of me to think they perhaps are.

Capt Pit Bull

8th Nov 2016, 17:28

My advice:

If you think an RA is not needed, follow it anyway. Generally the change to your flight path is quite small.

If there is some compelling reason not to follow it, or not to fully comply with it, do the best you can, in the correct sense. (e.g. Perf inhibitions are very approximate and wouldn't know, for example, that you are covered in ice. Maybe it asks for +1500 fpm and you can only coax +800).

Whatever you do, don't manoeuvre in the opposite sense to the RA. This is massively more dangerous than non compliance.

e.g. The lake Constance collision essentially involve 4 RA's. Only 1 was correctly complied with. 1 was correct sense, but insufficient magnitude. 2 were in the wrong sense.

squawkident.

8th Nov 2016, 17:56

My take on the term advisory is that it is not mandatory because I don't believe TCAS has a terrain warning included.

If RA says descend, you descend. If you hear GPWS Pull up, then up we go. In this case, the RA is not binding and thus is just advisory, whereas the GPWS is more pertinent..

Only other time I can think of ignoring this is in an emergency descent, possibly with an uncontrolled fire on board and perhaps in the circuit, if visual with all traffic and ATC are providing full coverage. Lastly, if the system is spurious, and only if this is confirmed, then i'll switch it off with a CB. Still not ignoring the RA however.

Failing this, I'M ALWAYS following RA.

overstress

8th Nov 2016, 18:30

In this case, the RA is not binding and thus is just advisory

Wrong. TCAS RA is mandatory. Unless it jeopardises the safety of the aircraft. In other words, follow it, don't assume the aircraft you can see is the one the TCAS RA is for.

RAT 5

8th Nov 2016, 18:47

Only other time I can think of ignoring this is in an emergency descent,

It's been thrashed to death before: but why were you not squawking TA Only. Also; how do we know about this non-compliance with the RA. Who told whom and how did the poster discover this snippet?

albatross

8th Nov 2016, 20:02

What does the Company ops manual say? What does the aircraft fright manual (deliberate misspelling) say? TCAS 1 or TCAS 2?
I found some ambiguity betwixt them and found that the subject was not covered well in neither recurrent training nor in sim training. ("we don't have time to discuss must tick other boxes"). Comments?

ATC Watcher

8th Nov 2016, 20:51

What does the aircraft fright manual (deliberate misspelling) say? TCAS 1 or TCAS 2?
you mean "flight manual " I guess :-)
TCAS1 is not for airliners, and I do not think it is even manufactured anymore (someone can correct me if I am wrong.) , ICAO/FAA/Eurocontrol mandates ACAS which is TCAS2 .
And yes always follow the RA.
As said here already making visual assessment is no guarantee the one you see is the one giving you the RA.

In this case lots of spin for a known problem occuring quite often : not reducing rate of climb/descent before level off.
As far as I have heard of this incident, the DA50 was cleared to FL360 ( 1000 below the 737) but because of high rate this generated RAs..
Separation was in fact never lost .( as the graph shows ) I would like to see the BFU report on that one , and not Av Herald account .

underfire

8th Nov 2016, 21:38

Wonder what happens when the aircraft is intercepted by a fighter jet!

galaxy flyer

8th Nov 2016, 21:47

It's been done and confused the target rather thoroughly. Tactical guys are briefed on potential TCAS confusion and have procedures to avoid it.

rab-k

8th Nov 2016, 21:49

The interceptor would switch off the Mode C/Mode S as they (visually) approach the target aircraft so as not to activate TCAS in either.

A problem with ignoring any RA on the basis of being "visual with the traffic" is where military traffic has caused the RA. There may well be two, (or more), and the one you can't see may be the real issue.

Locked door

8th Nov 2016, 21:56

Dear god please tell me the people advocating ignoring a TCAS RA are not professional pilots.

I'll put this in simple words. Never ever fail to follow a TCAS RA. I don't want to share the sky with you if you don't understand this. Even if you "think" you are visual with the conflicting traffic.

If you need evidence, read the Uberlingen accident report.

TCAS is the last, the final barrier between you and a mid air. If you receive an RA, EVERY OTHER DEFENCE AGAINST A MID AIR COLLISION HAS FAILED and you are in the last chance saloon.

LW20

8th Nov 2016, 22:04

Reading of "pilots" ignoring RA frightens me.

It's not only foolish, but also dangerous. You either haven't read your manuals, or you did not understand them. :ugh:

Metro man

8th Nov 2016, 22:54

Wasn't there an accident with a Russian airliner and a DHL cargo plane because the Russians obeyed the controller instead of the TCAS ?

Station_Calling

8th Nov 2016, 22:56

Yep, Uberlingen. Tragic for so many reasons, including the final act upon the controller.

https://en.wikipedia.org/wiki/Überlingen_mid-air_collision

evansb

9th Nov 2016, 01:54

Recalling the Uberlingen tragedy, years ago I attended an IFATCA conference where the subject of a seminar was an analysis of the Uberlingen mid-air collision. Using the Swiss Cheese (pun not intended) model of causation, my group's task was to determine the single incident that ultimately led up to the fatal collision. Several sessions involving hundreds controllers concluded the usual and predictable causes. Nothing really new was uncovered, but it was an informative exercise nonetheless. However my self and a Scottish controller were singled out as having the most correct and simultaneously useless answer to the question.

We both concluded that if the driver of the bus carrying the UNESCO committee passengers had NOT gotten lost enroute to the airport, the mid-air collision would not have occurred.

The answer was very correct, and very useless. Absolute truth is not always of absolute value.

P.S. No "millennials" were in authority at the time of the Uberlingen tragedy. When anyone singles out millennials or baby boomers or old folks or the younger generation, my eyes roll up so far into my head, enabling me to see old episodes of Heartbeat.

Dan Winterland

9th Nov 2016, 02:12

whereas the elevation element is very accurate - azimuth not so. The relative bearing of the threat can be up to 30 degrees out leading to a high likelihood of misidentification.

That's why you follow RAs.

underfire

9th Nov 2016, 03:02

and the GOL mid air collision? GOL turned off their transponder...and flew at a different level.

On September 29, 2006, GOL Airlines Flight 1907 flying at 37,000 feet collided in midair with an Embraer Legacy business jet over the Amazon jungle in Brazil. The badly-damaged business jet landed safely at a remote military base, but the GOL Airlines 737 was damaged too severely and crashed, tragically claiming the lives of the 154 passengers and crew aboard that flight. In the immediate aftermath of that tragedy, Brazilian authorities initiated criminal investigations and prosecuted the pilots of the business jet and the air traffic controllers. The actions by those authorities stand as the most noteworthy example of government criminalization of an aviation accident and caused many in the aviation industry to re-evaluate and refine their post-accident response procedures.

whereas the elevation element is very accurate - azimuth not so. The relative bearing of the threat can be up to 30 degrees out leading to a high likelihood of misidentification.

That's why you follow RAs.

Concur, due to the latency in both aircraft reporting systems, it seems best to follow the RA as it wants to always point you away from the perceived threat. tactically, we wont even go into the spoofing available with ADSB.

Capn Bloggs

9th Nov 2016, 03:23

While not wishing to belittle the danger of ignoring it, surely an advisory is just that, it's advice ie "guidance or recommendations offered with regard to prudent action". If, having received "the advice" you MUST take action, then surely it's no longer advice?

This forum is for professional pilots. :=

tactically, we wont even go into the spoofing available with ADSB.
Try to stay on-thread, please.

4468

9th Nov 2016, 03:53

Incidentally, a rather nasty TCAS incident is often quoted in my company, in which one a/c received a 'Climb' RA in response to a threat above it. (Both a/c were changing levels!) The crew of that same a/c saw fit, on the basis of visual acquisition, to 'manage' the demanded manoeuvre!

The very nasty 'reversal' of commands to both a/c, suggested this 'management' was unhelpful!

There are very, very, very few TCAS incidents in which a 'zero/zero' is predicted. This was one of them. Due entirely to 'managing' TCAS demands!

Frankly, I don't know why we even bother looking out the window after an RA. Just follow the commands. Tell ATC, and fill in the ASR after you land. Rather than hit the front pages of every newspaper on the planet!!!

AerocatS2A

9th Nov 2016, 04:56

I'll put this in simple words. Never ever fail to follow a TCAS RA. I don't want to share the sky with you if you don't understand this. Even if you "think" you are visual with the conflicting traffic.
...

TCAS is the last, the final barrier between you and a mid air. If you receive an RA, EVERY OTHER DEFENCE AGAINST A MID AIR COLLISION HAS FAILED and you are in the last chance saloon.

I agree with the basic sentiment, but never say "never".

I've had three TCAS RAs.

1. On descent into the circuit of an uncontrolled aerodrome with a relatively high rate of descent (~1500 fpm) we got a CLIMB RA triggered by an aircraft that was taking off. We were clearly going to pass behind it and level off at least 1000' above it. We followed the RA for all of the good reasons mentioned already in this thread.

2. At 200 feet on short final we received a DESCEND RA. Nope, not going to follow that one.

3. In the flare (same approach as number 2. above) again we received a DESCEND RA. Needless to say, we didn't follow that one either.

Number 2 and 3 were triggered by an aircraft on the ground with its transponder on and it turned out that our RADALT was sending bad info to our TCAS so the usual low level inhibits weren't active.

So yes, always follow the RA, except for when the system is obviously broken.

YRP

9th Nov 2016, 06:00

Incidentally, a rather nasty TCAS incident is often quoted in my company, in which one a/c received a 'Climb' RA in response to a threat above it. (Both a/c were changing levels!) The crew of that same a/c saw fit, on the basis of visual acquisition, to 'manage' the demanded manoeuvre!

Forgive me 4468, but I'm not following what happened.

By 'managed' you mean that they decide to ignore the RA and stayed level? And that led to a tighter conflict, near collision? Presumably that was because the other a/c was already descending and TCAS was telling it to descend assuming our protagonists were going to climb as directed?

ast83

9th Nov 2016, 06:24

Your reaction to an RA will be an instinctive one, whether ignored or followed. For me to ignore an RA I would have to recognise that following the RA would be in some way unsafe. Aerocat gave a couple of examples where this was essentially the case. I would like to know how the Enter air crew felt that following their RA would be unsafe. It appears that the reality is not that they deemed it unsafe, but rather unnecessary and IMHO, this is not a good enough reason to ignore.

It doesn't help, however, that the most common cause of an RA is essentially 'unnecessary' with ATC minimum separation not comprimised(2 aircraft cleared to climb and descend respectively to levels/altitudes with 1000' separation, both aircraft using high ROC/ROD).

SloppyJoe

9th Nov 2016, 06:35

It's been thrashed to death before: but why were you not squawking TA Only.

After a rapid decompression, pain, fogging etc, it is just possible that normal pilots would forget to initially select TA only prior to starting downhill. If only everyone were as good as you in these situations.

lederhosen

9th Nov 2016, 07:13

Heard an interesting one on frequency a couple of weeks ago. A Qatar heavy descending over the Balkans to get out of moderate turbulence had an RA with an aircraft going the other way as he was levelling off. The pilots thought it was a system error, the controller suggested that it might be due to turbulence. Anyone else come across anything similar?

recceguy

9th Nov 2016, 07:27

Apart from not being sure that the aircraft you have in sight is the one creating the TCAS alert, the main reason is that airline pilots are lacking any sort of training for positioning and manoeuvring in relation with other aircraft.
Ex-mil pilots got that training : fighter pilots of course but also transport dudes (which doesn't mean that they would extract themselves every time from a complicated situation, in a TMA for example with multiple intruders) (although some real fighter pilots have been practising 2 vs 2, or 4 vs 4) not mentioning rejoining tankers with multiple fighters all around, or fly-by with dozens of aircraft....

So in the meantime, and in the absence of better training, fly the TCAS orders !

Onceapilot

9th Nov 2016, 08:32

The subject has nothing to do with mil training or how good you think you are, learn and follow the TCAS rules.:mad:

Uplinker

9th Nov 2016, 08:52

Agreed. Even if we can spot another likely aircraft, how can we be sure it is the actual target of the RA?

Answer: We can't.

TCAS looks at all transponder equipped aircraft up to 80nm away including behind and to the sides of us and up to 9,900' above and below our own aircraft.

I might be able to spot aircraft in front of me, or a contrail, but I cannot see aircraft behind me, or to the side - behind the cockpit window field of view cut-off, or those directly above or below me. So it is very dangerous to assume that the one target one can see is the source of the RA.

An RA, incorrctly ignored on the basis of observation of an aircraft ahead might cause severe problems if the actual intruder was behind, directly above/below, or otherwise out of sight of one's own aircraft.

Don't even bother looking. Instead, if a TA is triggered; eyes inside onto the PFD and mentally review the actions and calls for an RA.:ok:

AerocatS2A

9th Nov 2016, 09:19

AercatS2A:

Can I suggest you don't fully understand how TCAS functions below 1000ft? This was reinforced by Eurocontrol in December 2007 by the following ;
Er, what makes you say that? Your quote agrees with my post.

deefer dog

9th Nov 2016, 10:19

golfbananajam

9th Nov 2016, 11:00

@Oxenos (post 14)

I fear you have missed part of the quote you posted, thus distorting the FAA Advisory Circular, though the guidance is itself contradictory

12.b. Pilot Responsibilities.
The intent of a TCAS is to serve as a backup to visual collision avoidance, application of right-of-way rules, and air traffic separation service. For TCAS to work as designed, immediate and correct crew response to TCAS advisories is essential. Delayed crew response or reluctance of a flightcrew to adjust the aircraft’s flightpath as advised by TCAS due to air traffic control (ATC) clearance provisions, fear of later FAA scrutiny, or other factors could significantly decrease or negate the protection afforded by TCAS. Flightcrews should respond to a TCAS in accordance with the following guidelines when responding to alerts:
(1) Respond to TAs by attempting to establish visual contact with the intruder aircraft
and other aircraft which may be in the vicinity. Coordinate to the degree possible with other crewmembers to assist in searching for traffic. Do not deviate from an assigned clearance based only on TA information. For any traffic acquired visually, continue to maintain safe separation in accordance with current regulations and good operating practices.
(2) When an RA occurs, the PF should respond immediately by directing attention to RA
displays and maneuver as indicated, unless doing so would jeopardize the safe operation of the flight or the flightcrew can ensure separation with the help of definitive visual acquisition of the aircraft causing the RA. By not responding to an RA, the flightcrew effectively takes responsibility for achieving safe separation. In so choosing, consider the following cautions:
(a) The traffic may also be equipped with TCAS and it may maneuver in response to
an RA coordinated with your own TCAS.
(b) The traffic acquired visually may not be the same traffic causing the RA.
(c) Visual perception of the encounter may be misleading. Unless it is unequivocally
clear that the target acquired visually is the one generating the RA and there are no complicating circumstances, the pilot’s instinctive reaction should always be to respond to RAs in the direction and to the degree displayed.

It also goes on to say

(16) The TCAS alone does not ensure safe separation in every case, nor diminish the
pilot’s basic authority and responsibility to ensure safe flight. TCAS does not respond to aircraft which are not transponder-equipped or to aircraft with a transponder failure, and can display erroneous indications when a transponder malfunctions. TCAS RAs may, in some cases, conflict with flightpath requirements due to terrain, such as an obstacle-limited climb segment or an approach to rising terrain. Since the basis for many approved instrument procedures and IFR clearances is avoiding high terrain or obstacles, it is particularly important that pilots maintain situational awareness (SA) and continue to use good operating practices and judgment when following TCAS RAs. Pilots should make frequent outside visual scans while using see-and-avoid techniques. Communication with ATC should be initiated as necessary.

FlightDetent

9th Nov 2016, 11:45

AerocatS2A

9th Nov 2016, 11:59

Aerocat what small cog is trying to get across to you is that correctly functioning TCAS installation will not generate a Descend RA if the aircraft is below 1,100 AGL. and it will not generate ANY RA once below 1,000 AGL.

When you received the Descend RA at 200 feet and then again while in the flare, something must have been working incorrectly in your airplane, or maybe you misunderstood what was being conveyed to you by the equipment.Yes, that is the point of my post. Did you read it?

Maybe it was unclear. I was providing an example of an occasion where you should not follow an RA. In my example, our RADALT was faulty and the TCAS inhibits were not active when they should have been. Hence we got an RA when we shouldn't have and so we didn't follow it.

Basil

9th Nov 2016, 12:31

I read Aerocat's initial comment as saying that, because of their height, there was clearly a defect so, of course, the RA was not complied with.
Seems clear to me.

alemaobaiano

9th Nov 2016, 12:57

GOL turned off their transponder

No, the Legacy was the one with the transponder turned off.

deefer dog

9th Nov 2016, 13:02

Aerocat, sorry I typed in haste, and having now re-read your post I see the point you are making.

oxenos

9th Nov 2016, 14:04

golf banana jam

I fear you have missed part of the quote you posted, thus distorting the FAA Advisory Circular, though the guidance is itself contradictory

In fact I deliberately omitted para(1) of the quote, as it specifically relates to TA.
The issue here relates to RAs

F-16GUY

9th Nov 2016, 20:28

Reading the last 3 pages illustrates that most pilots today are children of the magenta and would follow the magenta line blindly without asking any questions.

The FAA Advisory Circular posted by oxenos, clearly states that a pilot can, depending on the situation, disregard a RA if there is a good reason to do so or if visual with the RA traffic. Of course, the pilot then assumes responsibility for the deconfliction if electing not to follow the RA commands.

Quote:
"unless doing so would jeopardize the safe operation of the flight or the flightcrew can ensure separation with the help of definitive visual acquisition of the aircraft causing the RA. By not responding to an RA, the flightcrew effectively takes responsibility for achieving safe separation. "

Now, please explain to me why it is so bad to do as this crew did? If the conflicting traffic was the only traffic nearby, and they had obtained a visual, why not just steer clear?

If this is a professional pilots forum, then maybe one should start acting as pro, fly the f...... aircraft and take some responsibility, instead of following the magenta line blindly like a lemming.

Maintain aircraft control - Analyze the situation - Take appropriate action

73qanda

9th Nov 2016, 20:50

Also, whatever happened to airmanship? If you fly a high performance jet start thinking about reducing rates of descent or climb as you approach your assigned level and there is other traffic around. Simple airmanship.
Heavens above! Wouldn't that be dangerous? I mean.......you might have to come out of VNAV......would the wings even stay on?

AerocatS2A

9th Nov 2016, 20:59

Aerocat. While I agree with your valid point regarding an issue with your Radalt info, I don't agree that the other aircraft on the ground had any part in your RA.
That's where the TCAS display showed the intruder to be and there were no other aircraft airborne at the time. That's beside the point though, that a faulty TCAS can give you an RA that should not be followed.

FlyingStone

9th Nov 2016, 21:01

TCAS targets displayed on our NDs don't have the accuracy of an SSR or ADS-B. So even if the aircraft you see is in the same position as TCAS target, it might not be the only aircraft there or might not be the actual traffic at all.

Obviously there are times when it might be a good idea to disregard TCAS (RA below 900ft in case of equipment quirks as somebody described, etc.), but to disregard it in cruise, just because you think you might be visual with the correct aircraft. Also, TCAS is not a 2.5g manuever, nor does require any abrupt flight control movement - just a gentle pitch up/down to satisfy RA requirements. This of course takes into account that both aircraft compy with RA orders - otherwise the RA commands might require much higher ROD/ROC.

Not to be picky, but the FAA circular has no implication here. EU-registered aircraft operating in European airspace by an EU AOC holder. It is also Boeing procedure to follow any RAs unless below 1000ft or that visual contact requires other action (i.e. you follow RA and it looks something bad will happen anyway).

ACAS II overview | Eurocontrol (http://www.eurocontrol.int/articles/acas-ii-overview):

Pilots are required to immediately comply with all RAs, even if the RAs are contrary to ATC clearances or instructions, unless doing so would endanger the aircraft.

recceguy

10th Nov 2016, 01:02

The subject has nothing to do with mil training or how good you think you are, learn and follow the TCAS rules
That's exactly what I had been advocating - please re-read my post. The funny thing is that often, at the slightest mention of military operations, some colleagues will charge you with the worst possible offences, often in contradiction with what you had been saying

TCAS looks at all transponder equipped aircraft up to 80nm away including behind and to the sides of us and up to 9,900' above and below our own aircraft. I might be able to spot aircraft in front of me, or a contrail, but I cannot see aircraft behind me, or to the side - behind the cockpit window field of view cut-off, or those directly above or below me. So it is very dangerous to assume that the one target one can see is the source of the RA.
For your information only, that's what fighter pilots are required to perform during air combat - to keep a picture of what's happening above, beside and especially behind. So even if a TCAS can do better (and once again I'm not challenging that) it remains that people from that background will have a better instant understanding of what's happening - which once again, sorry to repeat for some, doesn't preclude following TCAS orders.

There was years ago a fascinating incident when a 747 captain was ordered by ATC to take an avoiding heading related to another aircraft - which he had on TCAS. The turn was to the right, and TCAS was showing the intruder on starboard. So he declined, ATC gave again the same order, which was declined again. ATC shouted an avoiding action, which was more abruptly denied... and so it went, up to a TCAS RA. Simply because the 747 captain (sort of civilian god having paid for his training ) had never heard of a triangle of speeds, or an intercept profile, which every fighter pilot - or Navy Officer out at sea ! - would have been familiar with.
On many TCAS, the bearing provided on the display is not so accurate - it's not an air-to-air radar, like what you have in a Mirage or F16 - but ATC, even the civilian, have all the software behind their screens, for the "interception" not to happen. Calculations are the same than in an air-to-air radar.

core_dump

10th Nov 2016, 05:39

If the RA is not for the aircraft you are visual with, then surely you have a TA for both? No need to discuss bearing errors and all that. If you have 2 aircraft at +/- whatever, then that's one thing. If only one is showing, that's quite another.

I find it unhelpful to compare this incident to one years ago where they did not have a visual.

peekay4

10th Nov 2016, 06:16

If the RA is not for the aircraft you are visual with, then surely you have a TA for both?
That assumes all aircraft have operating transponders, which might not be the case. There are many GA aircraft without transponders, or one might be inop, or a student pilot who accidentally left it at STBY, etc.

Herod

10th Nov 2016, 07:23

I've been reading this thread with interest. OK, I'll admit I've been out of the loop for twelve years now, but TCAS saved my butt a couple of times. My take on it is ALWAYS BELIEVE AND FOLLOW THE TCAS. (back to retirement)

nashama

10th Nov 2016, 07:52

AerocatS2A

10th Nov 2016, 08:00

Yes, even if ATC shout the opposite.

Capn Bloggs

10th Nov 2016, 08:26

Herod , " ...... ALWAYS BELIEVE AND FOLLOW THE TCAS"

Even if the ATC shouts to take the opposite evasive action?
Are you serious??

DaveReidUK

10th Nov 2016, 09:19

Has any one had his TCAS warning to descend and the ATC advising to climb up or vice versa??

You mean, apart from the Russian pilots at Überlingen ?

Who sadly didn't survive to tell the tale.

Una Due Tfc

10th Nov 2016, 10:06

You mean, apart from the Russian pilots at Überlingen ?

Who sadly didn't survive to tell the tale.

IIRC 6 months earlier A JAL 747 and DC10 came awfully close due to conflicting instructions from ATC and TCAS.

Dont Hang Up

10th Nov 2016, 11:00

Herod , " ...... ALWAYS BELIEVE AND FOLLOW THE TCAS"

Even if the ATC shouts to take the opposite evasive action?

Has any one had his TCAS warning to descend and the ATC advising to climb up or vice versa??
TCAS RAs must take precedence over ATC instructions. Controllers understand that and so should pilots.

The problem occurs when the controller becomes aware of a conflict late and will try to resolve it, but is unaware of the RA. The controller may have a completely valid conflict resolution which may be contradictory to the equally valid RA. The ability of the TCAS to co-ordinate both aircraft simultaneously (or instruct one aircraft with knowledge that the other is not RA capable) with none of the latencies of voice comms means it should always take precedence.

Modern surveillance systems are now able to downlink the RA information during the event. However providing this to the controller is a long way from universal. The purpose is not for the controller to intervene in the RA, but simply to be aware of its occurrence, not risk applying potentially contradictory instructions, and be ready to deal with any consequences involving, for example, reclearance.

Uplinker

10th Nov 2016, 11:39

@angryrat and Don'thangup: Absolutely.

1) TCAS RA's are a coordinated response between two conflicting aircraft. The TCAS units actually talk to each other and agree a course of action. One says, 'OK I will climb', the other says 'fair enough, I will descend' (or whatever). But the point is there is agreement and a coordinated response. This is far more exact, quicker and safer than a vocal exchange between aircraft and ATC, neither of whom - by definition - have spotted the conflict approaching until it is too late.

2) TCAS targets displayed on the ND or equivalent can be up to 30 degrees in error in azimuth. So are you really looking at the correct aircraft??

3) We can only see forwards from our cockpits and about 135 degrees to the right and left. We have very limited views below, and directly above. TCAS targets can be behind, above, below you or otherwise invisible to you. Many pilots seem only to think that the only conflict will be between two aircraft approaching each other more or less head-on.

4) Unless the sky is gin clear with no cloud, an intruder could very well be hidden from view.

5) As has been mentioned, very few of us have been trained in combat or avoidance manoeuvres (other than TCAS RA's). Even those that have are not in current combat practice, and our aircraft are not nimble fast jets either.

6) (And this is a note to self): There have been many cases of crews mishandling TCAS RA's. Time spent trying to spot an intruder aircraft would be much better spent looking inside at the PFD/ND and mentally rehearsing the RA manoeuvre.

oxenos

10th Nov 2016, 11:49

There seem to be a few people on here who are determined to justify not following an RA.
Let's try and simplicate it for you.
Following an RA may result in some minor inconvenience.
Not following an RA may result in your death, and the death of your crew and passengers, and the other aircraft's crew and passengers and maybe even some people on the ground.
Do you want to argue with that?

I do not often read R & N, and I post on it even more rarely. I can now see why some refer to it as Ravers & Nutters.

Jetjock330

10th Nov 2016, 12:56

We were doing TCAS RA's in the sim this week. A dual TCAS was given as a selection for the program, and the student elected to look out the window, and decided not to react correctly. They missed the fact the threat was from below, unseen and not the one they had in sight!
End of story!

FullWings

10th Nov 2016, 13:44

Following an RA may result in some minor inconvenience.
Not following an RA may result in your death, and the death of your crew and passengers, and the other aircraft's crew and passengers and maybe even some people on the ground.
Do you want to argue with that?
Well said.

Why not comply with RA demands? If they're followed in a reasonable timeframe it’s generally a gentle manoeuvre. Do you have 360deg vision above and below your aircraft? No. So just do it.

It’s not just your life you’re playing with, it’s all the others mentioned above. The only time I would even consider not following an RA would be if it was going to result in an immediate impact with terrain and how often does that happen?

If ATC said climb or descend you'd comply, yes? So what’s the problem complying with TCAS RAs, considering they have a higher priority than ATC clearances? There should be no confusion here.

PJ2

10th Nov 2016, 13:46

Next, we'll be arguing about ignoring EGPWS warnings.

Herod

10th Nov 2016, 14:04

Yep, and the earlier version (not "E") saved my butt as well.

PJ2

10th Nov 2016, 14:13

AirBlue A321 at Islamabad, Sukhoi demonstration flight at Mt. Salak...

Sure. There are rare, quasi-legitimate reasons for judging the veracity of these warnings. But the percentages are simply not there to do so.

I don't recall any reports in the literature that state that a mid-air collision was prevented by ignoring TCAS and following ATC instructions. We have the one case that demonstrates the opposite.

This is a by-the-numbers industry. The data just isn't there to support ignoring the warnings even when one thinks one's own judgement in-the-moment, is superior. One is just throwing dice by ignoring the engineering and the SOPs behind these systems.

peekay4

10th Nov 2016, 14:23

1) TCAS RA's are a coordinated response between two conflicting aircraft. The TCAS units actually talk to each other and agree a course of action.
Just to nitpick but RAs are not always coordinated. Coordinated RAs may happen if both aircraft are TCAS II equipped. But there are plenty of aircraft without TCAS II (and perhaps only Mode C/S).

If the other aircraft doesn't have TCAS II, an uncoordinated RA may be generated. That means there's a higher chance that the other pilot might make a conflicting evasive maneuver. Bottom line is to always be prepared for additional RAs (reversals, etc.)

Locked door

10th Nov 2016, 14:25

I still can't believe anyone who flies professionally is still advocating not following an RA.

This argument about ex mil pilots seeing and understanding better is a total red herring and shows a total lack of understanding of accident avoidance.

TCAS IS THE FINAL DEFENCE AGAINST A MID AIR COLLISION AND AN RA MUST ALWAYS BE FOLLOWED.

If you have a TCAS RA, 1) ATC have failed to separate you. 2) Your SA ref listening to other ac if on freq and knowing where they are has failed to separate you. 3) You have failed to acquire and visually separate yourself from other ac. 4) Every other method of separating you from other aircraft has failed.

Yes there is a possibility the RA has been caused by a high ROD/climb and if both aircraft adhere to their clearance separation will be maintained but you cannot assume that. Follow the RA.

TCAS is inhibited below 1000ft, and there is an SOP to not follow a TCAS descend RA below this height. A TCAS RA is not a violent manoeuvre.

Less well known is the reason behind the SOP radio call of "xxxxxx TCAS RA" which should be made in a timely, clear and unambiguous way when an RA is initiated. It is an instruction to ATC (and other AC) to cease all transmissions until the clear of conflict call is made to allow the manoeuvring crew(s) to concentrate on complying with the RA and prevent conflicting ATC avoiding instructions.

Again, in my best wide body jet shouty instructor / examiner voice

ALWAYS FOLLOW A TCAS RA.

You are in the last chance saloon and failing to follow an RA has killed far more people than it has saved. TCAS 2 is very reliable and rarely malfunctions.

misd-agin

10th Nov 2016, 15:33

Captain refused to follow RA. Said he saw the traffic and it wasn't a threat. FO's screaming that there are two targets. Captain was looking at the wrong one. Near miss!

vilas

10th Nov 2016, 17:01

In a RA there are always two or more players and RA is issued to all to take them through. Any body who wants to disregard RA without reason must also be clairvoyant to know the other aircraft's response. There may be RA reversals for them or he may also disregard his RA leading to chaos and dangerous situation. Only time you can consider is with a EGPWS alert.

F-16GUY

10th Nov 2016, 17:10

That assumes all aircraft have operating transponders, which might not be the case. There are many GA aircraft without transponders, or one might be inop, or a student pilot who accidentally left it at STBY, etc.

I have never seen any GA aircraft without transponders at FL360...

...but then again, it could surely happen.

Airmanship and SA goes hand in hand. No SA, outside controlled airspace and with more than one target on TCAS, sure I will follow it, but if only one target at FL360 in controlled airspace and visual (since 80 miles in the contrails) plus maybe SA from ATC communication, I will assume the responsibility and ensure positiv separation by creating line of sight to the other aircraft.

RAT 5

10th Nov 2016, 17:19

Some guys seem to have loss the will to survive. It's like my wife; I issue an order camouflaged as a suggestion; she thinks about it and tries to find a reason not to agree or come up with an absurd alternative. This takes quite a few moments, and my response is pointing out her counter suggestion is not practical. After a few ping-pong comments we agree, finally, that my original idea will work as the best option and off we go.
Now have this discussion with a closing speed of 16km's per minute. There comes a time for someone to make a decision PDQ. If you want to think about it afterwards, feel free. At least you will have the luxury. If you don't...............then you won't.

PJ2

10th Nov 2016, 17:56

Peekay4;

Just to watch how the system handled multiple TAs/RAs, we used the simulator to put several aircraft above & below our "aircraft". The TCAS handled normal RAs & reversal RAs well.

Indeed, one must be prepared for additional RAs.

And, as the literature states, the manoeuvres do not require brisk or high 'g' loadings.

Sidestick_n_Rudder

10th Nov 2016, 18:17

I'm with F16GUY on this. TCAS RA's should be generally followed, no one is arguing this. However, if the situation is obvious (eg. VMC, one target only and one can unambiguously determine it is not a threat), are we supposed to follow, just because the computer says so?!

Same for eg. spurious GPWS warning in VMC (had it 2 times), "long flare" warning that got the EK777 into trouble at DXB, or the instance wher the EK A380 couldn't land at MAN and diverted, because the ROPS system said "no", even though the rwy length was more than sufficient. I feel sometimes we are doing things contrary to common sense, just to make the computer happy.

PJ2

10th Nov 2016, 18:30

Sidestick...

Again, we're back to data, which is the basis for operations. The exceptions cited are rare.

Spurious warnings mandate a report so it can be fixed. If a ROPS system is indicating "no" when the runway is deemed sufficient, then fix the ROPS system so that it provides accurate information. (I was under the impression, perhaps false?, that the EK777 fell back to the runway because the PF/crew had not applied go-around thrust)

Sidestick_n_Rudder

10th Nov 2016, 18:42

Yes, these systems generally work well and I am not trying to advocate ignoring them.

The exceptions cited are quite rare, but far from remote. Every now and then it's plainly obvious the computer has gone haywire, or its output is not relevant under prevailing circumstances. What I'm against is following the computer slavishly, even when it obviously doesn't make sense. The FAA stance on TCAS quoted earlier seems to be in accordance with that.

As for the EK777 at DXB. Yes, it was a mis-handled g/a. However, the whole event was triggered by "long flare" warning issued at ~1000m deep into a 4000m runway. Was it a cause of the accident? No. A contributing factor? Yes, in my opinion at least. What would have happened, had the crew continued the landing? Nothing.

Mikehotel152

10th Nov 2016, 19:17

You cannot compare flying an F-16 with a bubble canopy in airspace cleared of other traffic apart from yourself and a few other mavericks, with flying a large metal tube filled with 200 human lives in busy airspace.

I had an RA going into Madrid a few days ago. The business jet pilot was descending quickly without looking outside his cockpit, hence he didn't see the 737 in front and below him, leading to an RA. We continued to descend and his RA presumably told him to climb. ATC finally caught up with the dangerous situation they had created and told the business jet to level off.

The point is that there is no way we could have known about the business jet because he was trying to land on us from behind and I suspect his view of us was obscured by his lobster thermidor. So, TCASII saved the day.

Follow the farking TCAS RA. It's got nothing to do with Magenta lines.

AerocatS2A

10th Nov 2016, 20:35

I have never seen any GA aircraft without transponders at FL360...

...but then again, it could surely happen.

Airmanship and SA goes hand in hand. No SA, outside controlled airspace and with more than one target on TCAS, sure I will follow it, but if only one target at FL360 in controlled airspace and visual (since 80 miles in the contrails) plus maybe SA from ATC communication, I will assume the responsibility and ensure positiv separation by creating line of sight to the other aircraft.
Or you could just pitch up or down a couple of degrees and say "TCAS RA" on the radio. Then a few seconds later, once the TCAS is happy, you say "clear of conflict, returning to flight level 360" and gently return to your assigned level. It's not hard.

Capt Ecureuil

10th Nov 2016, 20:52

With you on that.

F16GUY is supposedly a Flight Safety Officer too, I wonder if he says "I" when the rest of us say "we"

F-16GUY

10th Nov 2016, 20:55

angryrat,

Not all rules and regs are black and white. They leave room for common sense. In western Air forces we learn that "Flexibility is the key to Airpower". Civilian pilots can translate that to "Flexibility is the key to efficiency". Using common sense and being flexible within the confines of the rules is what separates the exceptional pilots from the average ones.

Mikehotel152,

Of course you can't compare flying the F-16 in segregated airspace while GCI controllers try to vector you towards your opponent (total opposite ATC controllers who vector you away), with flying a widebody liner in busy terminal airspace, with all the bells and whistles doing the flying for you while the guy/gal next to you work the radio, FMS etc. for you, and even monitors you to ensure you dont make any mistakes. It must be the most challenging job in the world, especially having to know which protections are lost in alternate law and how the TOGA switch works and interacts with the auto throttle if pressed on the ground....

Irony Off!

As Sidestick_n_Rudder noted, I to would follow the RA in most circumstances and definitely in a situation as the one you describe. But if met with a situation like the one I described earlier, and if in possession of full SA on the only traffic within miles, I would use common sense and be an effective pilot.

F-16GUY

10th Nov 2016, 21:13

Or you could just pitch up or down a couple of degrees and say "TCAS RA" on the radio. Then a few seconds later, once the TCAS is happy, you say "clear of conflict, returning to flight level 360" and gently return to your assigned level. It's not hard.

No its not hard at all. It is as easy as turning 10 degrees left or right and then returning to the original track once positive separation is ensured. I will do what ever makes sense in the situation and not whatever satisfies the TCAS (in this case, but as implied earlier, I will satisfy TCAS in most situations).

I find it funny that so many here actually perceive this issue as 100% black and white. Aviation in general is by far back and white.

The Blu Riband

10th Nov 2016, 21:13

I to would follow the RA in most circumstances and definitely in a situation as the one you describe. But if met with a situation like the one I described earlier, and if in possession of full SA on the only traffic within miles, I would use common sense and be an effective pilot.

No, you wouldn't be. You'd have been wilfully negligent and deliberately endangered your pax, crew and a/c.

In the US , and almost all global FIRs, you are required to follow all TCAS RA's. End of.

F-16GUY

10th Nov 2016, 21:21

I wonder if he says "I" when the rest of us say "we"

Glad to know that some sort of mental proces is going on. I only wish it would relate to the tread.

F-16GUY

10th Nov 2016, 21:27

No, you wouldn't be. You'd have been wilfully negligent and deliberately endangered your pax, crew and a/c.

In the US , and almost all global FIRs, you are required to follow all TCAS RA's. End of.

Is that so? Please present to me the evidence in form of the regulations that states "The pilot shall" and not "the pilot should".

FlyingStone

10th Nov 2016, 21:36

ICAO Doc. 8168, Vol. 1, Chapter 3.2:

c) in the event of an RA, pilots shall:
1) respond immediately by following the RA as indicated, unless doing so would jeopardize the safety of the
aeroplane;
Note 1.— Stall warning, wind shear, and ground proximity warning system alerts have precedence over
ACAS.
Note 2.— Visually acquired traffic may not be the same traffic causing an RA. Visual perception of an
encounter may be misleading, particularly at night.
2) follow the RA even if there is a conflict between the RA and an air traffic control (ATC) instruction to
manoeuvre;
3) not manoeuvre in the opposite sense to an RA;
Note.— In the case of an ACAS-ACAS coordinated encounter, the RAs complement each other in order
to reduce the potential for collision. Manoeuvres, or lack of manoeuvres, that result in vertical rates
opposite to the sense of an RA could result in a collision with the intruder aircraft.

Mikehotel152

10th Nov 2016, 22:00

Of course you can't compare flying the F-16 in segregated airspace while GCI controllers try to vector you towards your opponent (total opposite ATC controllers who vector you away), with flying a widebody liner in busy terminal airspace, with all the bells and whistles doing the flying for you while the guy/gal next to you work the radio, FMS etc. for you, and even monitors you to ensure you dont make any mistakes. It must be the most challenging job in the world, especially having to know which protections are lost in alternate law and how the TOGA switch works and interacts with the auto throttle if pressed on the ground....

What on earth are you talking about?

Back to the topic please.

framer

10th Nov 2016, 22:18

He is talking about how easy it is to fly an airliner compared to flying an F-16 on tactical ops, the reason for talking about it at every opportunity is to reinforcie his/ her long held and promoted belief that he/she is better than most. If you keep peeling back the layers bit by bit ( it usually takes a few weeks) the root of this sort of behaviour is normally fear.

Una Due Tfc

11th Nov 2016, 00:40

Indeed, stating "callsign123 TCAS RA/Climb/Descent" is extremely important for me as an ATCO because it tells me to shut the eff up and leave you to it.

Forgive my ignorance but my training has always taught me that TCAS RAs MUST be complied with. As has been stated already there have been fatal incidents in the past where crews acquired visual with what they perceived to be the conflicting traffic only to hit someone else.

There have been crews who have refused avoiding action because the turn was towards the traffic, not realising turning one aircraft to pass behind the other is the quickest and safest resolution (unless using totally parallel tracks, but that's rarely practical ....I mean eventually you need to reach destination....).

What's the worst that happens if you follow an RA at altitude? You set off a domino RA on traffic above/below you, maybe get a reversal. From ignoring one? You kill hundreds of people you absolute w***er....the fact we are even having this debate is frightening. It's all well and good having the discretion to ignore one but for God sake unless you KNOW the system is malfunctioning (IE below 1,000 ft) then stop measuring your d*** and just play it safe.

This is by far the most frightening thread I have ever read on this site.

learner001

11th Nov 2016, 02:44

Seems like some in here are not adequately trained, not 'active', not 'current', or not 'up to date' on TCAS procedures, which are constantly analysed and updated/altered after lessons learnt.

Sidestick_n_Rudder

11th Nov 2016, 06:47

@Flying Stone,

Since you're quoting ICAO DOC 8168, please find the following passage from the same document:

3.1.3 Nothing in the procedures specified in 3.2 hereunder shall prevent pilots-in-command from exercising their best judgment and full authority in the choice of the best course of action to resolve a traffic conflict or avert a potential collision.

That's basically the point I'm trying to make.

F-16GUY

11th Nov 2016, 07:11

ICAO Doc. 8168, Vol. 1, Chapter 3.2:

Admitted, the ICAO document uses the phrase "shall" in chapter 3.2
But it also has the following "disclaimer" to the wording in said chapter:

"3.1.2 Nothing in the procedures specified in 3.2, “Use of ACAS indicators”, shall prevent pilots-in-command from exercising their best judgement and full authority in the choice of the best course of action to resolve a traffic conflict or avert a potential collision."

In other words, the pilot in command can use his judgement (common sense) to resolve any issue.

Same goes for the pilot of the Emirates 777. Obviously it would have helped to know how the TOGA switch works, but using good judgement and landing a bit long on a looooong runway, instead of following the SOP blindly, might have put him in a more favorable situation.

Here is a TCAS story from real life. There I was....

Flying a Close Air Support training mission as a singleton, in Class E airspace, in an area that was notamed "Increased Military Flying Activity", I was orbiting in a right hand 5nm wheel around the practice target at FL125 with 450KTS.
Only other traffic in the vicinity is a 737 on the same frequency on its way to a nearby airfield 40nm away. The controller calls him out when he is 30nm away. I see him on the surveillance picture, my interrogator shows him, and when within the search volume of the FCR I see him on the radarscope. I acquire him visually at 12-15nm and call it out to the controller.
The 737 pilot gets the traffic call as well. His replay is that he has me on TCAS, and at 10 miles or so he also calls visual the F-16, no conflict.
If I continue my turn and if he continues with his present heading and altitude there will be no conflict and I will pass him on his left side (with my left side) at a range of 3-4nm.
Then, as my vector crosses his vector during my turn, I see him starting to maneuver and hear him call RA to the controller. I am puzzled and so is the controller who asks him "didn't you say you were visual, no conflict?".
Afterwards I got words, that during his "by the book" reaction, he managed to injure one of his flight attendants who was not strapped in and scare the living crap out of his passangers.

How would any of you TCAS users have reacted in the same situation? Remember, only 2 aircraft within miles (you and the F-16), both visual, the F-16 flying VFR, you flying IFR in VMC conditions.

framer and MikeHotel152,

That was my take at being sarcastic. Apparently your sense of humor is different from mine. You can not compare flying fighters with flying jetliners. Both things have different challenges and different procedures. One thing that is the same though is the requirement for all pilots to exhibit good airmanship, common sense and judgement. Because sometimes pilots will face situations that are not described in the manuals and where following regulations blindly (be it SOP's, government or international regulations) is not the safest and best course of action. I know plenty of civilian and military pilots who exhibits good airmanship, common sense and good judgement, and most of them, my self included, have learned valuable lessons from situations where one or all three things could have been better.

Thats it for me, I will knock this discussion off and return to homeplate. SeeYa

Edit: Sidestick_n_Rudder beat me to it

Herod

11th Nov 2016, 07:34

As I recall, the UK ANO has (or had) the phrase "nothing in this Order shall prevent the pilot-in-command from carrying out any action he considers necessary to protect the aircraft, passengers and crew". This allows you to fly inverted through Tower Bridge, but you'd better be able to justify it to the authorities. How do you justify "I chose to ignore the RA, for the safety of the aircraft etc, and in the process killed 200+ people"?

Sidestick_n_Rudder

11th Nov 2016, 08:18

@F16GUY - you can be my wingman anytime! :ok:

IcePack

11th Nov 2016, 08:18

F16-guy suspect 737 over reacted to RA. At levels around 10000' you only need a pitch change around 4 deg to comply. IMHO the 737 got a shock when the RA triggered making the pilot believe their was another aircraft in the vacinity that he/she had not seen.
However I think he did the right thing in complying no choice really.

AerocatS2A

11th Nov 2016, 08:34

B737 was correct in responding to the TCAS, but used incorrect technique. Know what's required to get the vertical speed you need. 1 degree pitch changes is approximately your mach number x 1000 in fpm change. Flying level at M0.8 then you only need two degrees pitch up to achieve a climb rate of 1600 fpm.

And now I think Framer was correct, when you strip the layers away you find fear.

BizJetJock

11th Nov 2016, 09:23

Certainly if you injure a cabin crew with your maneovring then you have incorrectly responded to the RA. Does that mean he shouldn't have responded? Of course not; he may have the other aircraft in sight, but particularly since he doesn't have accurate information on the military aircraft's pitch and turn rates, he cannot possibly judge whether the RA is in some way invalid.
And of course, all this willy waving by military guys about how they are able to judge situations perfectly with their superpowers has to be read in the context of the thread over on the miltary forum about the recent collision between two F18s, and how the rate of such accidents is causing concern among the military powers-that-be. :ugh:

framer

11th Nov 2016, 09:36

Surely we didn't just get another story about flying F-16's? If we were in a pub people would be drifting off to another table :)

ATC Watcher

11th Nov 2016, 12:00

Reading some of the posts here makes me almost wanting to give up. The 2001 lessons ( JAL/JAL in Japan and Ueberlingen ) which led to a drastic modification of the ICAO ACAS procedures (i.e basically always follow the RA) , seemed to be forgotten , and we are slowly getting back to square one.
Seeing the number of RA non-compliance serious incidents on the raise again, it is only a matter of time until we will have a most serious case.
Good example (repeat of Ueberlingen scenario) here : http://www.mot.gov.sg/uploadedFiles/Ministry_of_Transport/Content_Blocks/About_MOT/Air_Transport/AAIB/SQ61%20loss%20of%20separation%203%20Jul%2014%20-%20FR%202015-11-11.pdf

When I see F/As injured as a result of following a TCAS RA I wonder if the guy in front even read the manual...:ugh:

beardy

11th Nov 2016, 12:20

Mikehotel152

11th Nov 2016, 12:31

If that's the most relevant example the F-16 can recall which supports his argument that a pilot's first reaction to a TCAS RA is to comply, he misses the point.

In my example of a TCAS RA which occured recently, we could NOT see the airplane that was overtaking us from behind and above while both of us were in a descent while under ATC control.

Unlike the beautiful F-16, the venerable 737 has no field of view behind the wingtip or indeed behind or below at all.

Therefore a commercial jet pilot's first reaction should be to comply with an RA just in case . We do not have an ejector seat or parachutes, and neither do any of the other 195 souls on board.

As for the 737 pilot who caused injuries to crew due to his over-reaction to the RA, this is still preferable to no reaction at all.

OldLurker

11th Nov 2016, 13:20

Surely following an RA is NEVER dangerous (unless it is to descend below Safety Altitude), NOT following an RA MAY be dangerous. Hence following an RA is ALWAYS safe (bearing in mind the caveat of Safety Altitude). Not following an RA MAY be unsafe, so don't do it, it can never be justified on safety grounds: always, always, always, follow the RA and be SAFE.

Simple really Not that simple.

An example was given up-thread (#35) of a case where following an RA would have been dangerous. In the case quoted, the danger was (a) obvious and (b) due to equipment failure external to the TCAS, but that doesn't alter the fact that the TCAS could and did give an incorrect indication which should not have been followed.

If you always, always, always follow an RA, what are you there for? Why isn't the TCAS linked directly to the flight controls to make the aircraft do what it says? Because nobody with any sense trusts any automatic system to always, always, always work correctly. 99% of the time, maybe 99.5%, but not 100%. The 0.5% is why you're there, and why the ICAO document says "Nothing in the procedures specified ... shall prevent pilots-in-command from exercising their best judgment and full authority in the choice of the best course of action to resolve a traffic conflict or avert a potential collision." To adapt an old saying, engage brain before operating controls.

In this way, TCAS is much like a car's satnav (though much more complex). 99.5% of the time your satnav gives you correct guidance. The 0.5% is when it tells you to drive off the dock into the water.

Brian W May

11th Nov 2016, 13:47

The danger of ignoring an RA is that you assume that the aircraft you can see is the one which triggered the TCAS. The Tcas may be warning of another aircraft which you have not seen.

Quite, but with one aircraft on the scope at the correct bearing and no other traffic, it was safe to assume as you can only get a warning from traffic that shows.

Exactly my point regarding having a human on the flight deck . . . Also my point that if there is doubt, then there is no doubt.

The Blu Riband

11th Nov 2016, 14:10

Our QRH says:

In the event of a ......... RA accomplish the following by recall:

and then details how to mn'vre in more detail.
There is no discretion.

F16 guy - I have the distinct impression that you're 12 , and playing an ego game.

Remember that many of us probably have more single seat time than you so no need for the war stories. TCAS and GPWS equipment failure or erroneous displays are almost unheard of nowadays and many int'l airports are so busy that to even consider not following the TCAS (which is now very sophisticated) could cause a fatal delay.

beardy

11th Nov 2016, 14:18

OldLurker,
Having reread #35 as you must have done and reread my caveat about not descending below SA, yes it really is that simple and yes you will get a descend below SA, which is why you and I are there.
There is no excuse for not following an RA (unless SA impinges on your trajectory and you would fly into the ground)

Brian W May: You can never be sure that the one you have seen is the one TCAS RA is alerting you to, nor that simply because the 'scope' sees one there is ONLY one.

learner001

11th Nov 2016, 15:28

Like anything...

Lack of knowledge and the 'surprise part' usually induces OVERREACTION !!!:ooh:
See this over and over again during sim training.

TCAS compliance needs education and REGULAR TRAINING.
(Just like our half-yearly, regular engine failure procedures training.)

Relax... People in the back (should) not even notice a reacting on a TCAS RA . . .:zzz:

ATC Watcher

11th Nov 2016, 15:38

Guys, this is an academic discussion . I am following TCAS from the ATC side since its introduction, and I have never seen or heard of an RA that , if followed would have resulted in an accident , even with initial version 6.04 which was quite bad.
But there are almost a hundred cases by now where not following and manoeuvring against it caused loss of separation , and even a collision ( Ueberlingen)

Anyway the future will solve this , on the A380, A350 (and I believe on all the neos but not 100% sure ) the ACAS is embedded in the Flight Director , so RAs are automatically flown by the auto pilot.
Of course there is a button to disconnect , but I have never heard of anyone doing that in real life. Crew operating those aircraft in their vast majority praise the system .

learner001 : just saw your post ; 100% with you there . Good reminder !

olster

11th Nov 2016, 16:09

The A380 has an automated TCAS system that reacts to an RA (former instructor). To my professional pilot colleagues: if you do not react appropriately to a TCAS RA you are criminally irresponsible and should not be doing the job. What part of that is difficult to understand?

olster

11th Nov 2016, 16:47

And another thing: for all the 'aces' out there. As we all (should) know TCAS RA manoeuvres are practiced and examined through the mandatory recurrent LPC system here in the UK. The TRE will be looking for the correct response to the simulated RA. Why not try ignoring the RA and tell the examiner that you are going to visually miss the traffic? See how that goes. I find it unbelievable that professional pilots do not understand the imperative of correct response to an RA. It disturbs me that I share the same airspace.

Onceapilot

11th Nov 2016, 18:45

Despite this being a "rumours and news" page, the moderators have allowed stupid trolling posts that attempt to undermine the sound basis of TCAS SOP. Mods, please remove posts that advocate anything other than compliance with TCAS SOP. Thanks

Sidestick_n_Rudder

11th Nov 2016, 19:29

Should the Mods also delete the quoted FAA and ICAO regulations as "non-kosher"?

Seriously, why are some guys throwing a fit, just because someone has a different opinion. Take chill pill, it's just a discussion! :ugh:

AerocatS2A

11th Nov 2016, 19:53

Because these different opinions have killed people in the past, that's why.

Capt Ecureuil

11th Nov 2016, 20:31

Take a chill pill? You are kidding but more like trolling.

There is no discussion!

Please do as you advocate on your next sim detail and decide not to follow an RA, the sky will be a safer place for us all.

AerocatS2A

11th Nov 2016, 20:36

Should the Mods also delete the quoted FAA and ICAO regulations as "non-kosher"?

The problem with the weasel words in the ICAO docs is that they are intended to allow a pilot to not follow an RA if it would be more dangerous to do so than to risk a collision, example: getting a "climb" RA that is beyond the performance of the aircraft. But some pilots, like F16 above, think it means they can basically do what they want. If they think they have full SA then they can do a non RA manoeuvre instead. That is not the case though, if it is a genuine RA and it's not going to put you into the ground or cause you to stall, then FOLLOW IT! More importantly, if you, for whatever reason, won't, or can't follow it, then do NOTHING, don't do a non TCAS manoeuvre in an attempt to avoid the target aircraft.

If there are so few aircraft in the area that you think you can positively identify the intruder aircraft then you won't come to any harm by following the RA. If there are enough aircraft around that you can't positively identify the intruder aircraft then you must follow the RA. In both cases, just follow the RA.

ManaAdaSystem

11th Nov 2016, 21:21

Why isn't the TCAS linked directly to the flight controls to make the aircraft do what it says? Because nobody with any sense trusts any automatic system to always, always, always work correctly. 99% of the time, maybe 99.5%, but not 100%.

Newer models of Airbus have automated TCAS systems. The aircraft will take evasive action all by itself.

Enhancing flight safety during TCAS manoeuvres
20 AUGUST 2009 PRESS RELEASE
Enhancing flight safety during TCAS manoeuvres

Following recent successful development testing, a new Auto-Pilot/Flight-Director (AP/FD) TCAS* mode for the Airbus A380 has been approved and certified by the European Aviation Safety Agency (EASA).

The main benefit of the system is that it could further enhance safety during a traffic avoidance situation because the pilot can now fly the aircraft without switching out of one mode and into another. Thus, by simplifying the actions required by the pilot during a TCAS manoeuvre, this enhanced TCAS mode minimises potential overreactions or inverse reactions while preserving his or her concentration at a critical time.

In addition to now being certified on the A380, the AP/FD TCAS mode will also become available for retrofit on other Airbus Fly-By-Wire aircraft in the coming years.

AP/FD TCAS operation overview
The new AP/FD TCAS mode essentially completes the existing TCAS functionality by implementing a TCAS vertical guidance feature into the Auto Flight computer. The result is that now the Auto Flight computer can control the vertical speed of the aircraft which is adapted to each resolution advisory acquired from TCAS.

Moreover, with this new AP/FD TCAS mode activated, when a TCAS "Resolution Advisory" (RA) is received, the pilot no longer needs to disengage the autopilot or Flight Director before conducting the TCAS manoeuvres. Rather, the autopilot can now automatically conduct the correct TCAS manoeuvre, to position the aircraft clear of any potential traffic conflict.

Furthermore, in the case of the pilot flying the aircraft manually (i.e. without autopilot engaged) when a RA is received, previously the Flight Director 'pitch bar guidance' - indicated on the Primary Flight Display - had to be switched off, but with the new mode, the Flight Director bars remain active and smoothly guide pilot to fly the TCAS manoeuvre. At any time, the crew still retains the ability to override the proposed manoeuvre, so as to respond manually to a TCAS RA by flying according to "conventional" TCAS procedures, i.e. manually controlling the vertical speed by referring to TCAS indications on the pilot's vertical speed scale.

* Background to TCAS - Editors' note:
The 'Traffic Alert and Collision Avoidance System' - known as 'TCAS' - is designed to scan for, detect, and interrogate the transponders of other aircraft in the nearby airspace vicinity. It then uses the received transponder signals to compute a distance, bearing and altitude relative to the nearby aircraft. The evaluated traffic information is displayed as symbols on the Navigation Display. As TCAS checks the other aircraft?s relative distance permanently in short-time intervals, it can, therefore, also calculate the other aircraft?s closure rate relative to its own aircraft position. When TCAS detects that an aircraft's distance or closure rate becomes critical, it generates aural and visual annunciations for the pilots. Mandated on aircraft carrying more than 30 passengers since 1993, TCAS is now compulsory on all aircraft types.

Basil

12th Nov 2016, 07:05

Newer models of Airbus have automated TCAS systems. The aircraft will take evasive action all by itself.

2. At 200 feet on short final we received a DESCEND RA. Nope, not going to follow that one.

3. In the flare (same approach as number 2. above) again we received a DESCEND RA. Needless to say, we didn't follow that one either.

Number 2 and 3 were triggered by an aircraft on the ground with its transponder on and it turned out that our RADALT was sending bad info to our TCAS so the usual low level inhibits weren't active.

So yes, always follow the RA, except for when the system is obviously broken.

I wonder what additional protections the AirBus system has to avoid the situation mentioned by Aerocat?

Fly3

12th Nov 2016, 07:32

I don't believe it's possible to get a Descent RA that close to the ground. The system will have switched to TA only by then I think.

ATC Watcher

12th Nov 2016, 07:33

Basil : I wonder what additional protections the AirBus system has to avoid the situation mentioned by Aerocar?T
The partial answer was in Aerocar message : our RADALT was sending bad info
Question is : is this a regular event or 1 in the minus 6 , or a more Boeing problem? ( e.g. TK1951 in AMS)

AerocatS2A

12th Nov 2016, 08:47

It was a Dash 8. It was several years ago that it happened, but I think the radalt wasn't sending any info at all to the TCAS so the TCAS low level inhibits weren't active. I don't know enough about that specific system to know how likely it is to happen again. Airline pilots fly with stick pushers that are also capable of pushing the nose towards the deck at low level but a bit of fail safe engineering makes that very unlikely. We have five seconds to respond to an RA, if a fully automated system announced the RA then paused for a couple of seconds prior to flying the manoeuvre then we'd have a reasonable chance of disconnecting the autopilot in time to prevent an unsafe RA.

Lancelot de boyles

12th Nov 2016, 08:56

It seems to me that those advocating not following an RA are extracting the one caveat from the regs/docs that suits them, without understanding, or choosing not to understand, the full document or operation of TCAS.
Maybe training and understanding of TCAS is deficient in their organisations?

Yes, the PIC has the option not to follow an RA, just as the PIC has the option to not follow other warnings and best practices, if in their judgement, it is safer to do so.

But TCAS is collaborative. It functions based on the actions that two or more aircraft crews are going to take to resolve a conflict.
If one crew is only ever going to assess the situation and choose by themselves what to do, then surely the correct mode for that crew to operate in is

TA-only ?

In this way, any other aircraft in the scenario will have RAs that take into account this response.
The same mode as when you are engaged in an emergency descent, an engine out, or the mode that should be automatic in certain parts of the flight, such as close to terrain (unless the system has a problem)

BTW. In case of any pedants reading this, I am not advocating to operate in TA mode only.

Surely the training should be- Follow the RA. It's a really easy manouver, which takes a couple of minutes to train in the sim, unless you are ham fisted. In which case ask for a little more time to train in this complex manouver.
Your situational awareness cannot take into account what actions those many other aircraft around you are taking, until they have clearly taken it.

ManaAdaSystem

12th Nov 2016, 11:04

I wonder what additional protections the AirBus system has to avoid the situation mentioned by Aerocar?

I believe even the Airbus has an autopilot disconnect button?
What do you do if you do an autoland and the aircraft misbehaves (if you are not a SQ pilot, that is)?
All automatic systems can fail.
I suspect Airbus automated the TCAS because we, even after what we have learned, what we have trained and after a number of people got killed, still have pilots out there who think they know better.

olster

12th Nov 2016, 11:36

Correct MAS. The A380 automated TCAS / RA response feature from the operational perspective prescribes a rigid FMA adherance. In the unlikely event that the automation does not work there is a back up sop to fly the manoeuvre manually. The automation is incorporated in both f/d and a/p modes. Whether you are flying a fully automated A380 /A350 or a less sophisticated aircraft you must follow the RA even @ aircraft certified ceiling. Regardless of 'taking a chill pill' any alternative is ill - informed drivel. As I stated before, any professional pilot on this site who thinks differently why not 'debate' the point with your TRE on your next LPC.

Derfred

12th Nov 2016, 19:20

I think what that F16 pilot fails to understand is the consequence of his actions on the other aircraft and it's passengers.

He has already caused an unnecessary RA to a passenger carrying aircraft which resulted in injury and still hasn't learned.

What he also doesn't understand is that passenger carrying airliners have more than one pilot. If the pilot flying decides to ignore an RA, how does he/she confer with the other pilot on the flight deck that they are doing so to "increase safety" (unless it's obvious or SOP such as below 1000' RA).

The only way to defend ignoring an RA is that if following it would have jeopardised the safety of the aircraft. In F16's examples, that is clearly not the case.

4468

12th Nov 2016, 22:38

Couldn't agree more TangoAlphad

Some single seat pilots find the transfer to a twin pilot world terribly difficult!:rolleyes:

The lack of psychic abilities in their co-workers must be enormously frustrating!

Farrell

13th Nov 2016, 08:17

ICAO DOC 8168 - Aircraft Operations:

"in
the event of an RA, pilots shall:
1) respond immediately by following the RA as indicated, unless doing so would jeopardize the safety of the aeroplane;
Note 1.— Stall warning, wind shear, and ground proximity warning system alerts have precedence over ACAS.
Note 2.— Visually acquired traffic may not be the same traffic causing an RA. Visual perception of an encounter may be misleading, particularly at night.

DaveReidUK

13th Nov 2016, 08:56

Already quoted in post #97.

wiggy

13th Nov 2016, 10:35

Note 2.— Visually acquired traffic may not be the same traffic causing an RA. Visual perception of an encounter may be misleading, particularly at night

As I recall it there was an old adage in the fighter world along the lines of "It's the one you don't see that gets you..."

Might still be worth bearing in mind..................

RAT 5

13th Nov 2016, 10:43

Not wishing to support ignoring an RA, but: F16Guy is in an a/c with vast spectrum of electronics sensors, displays of a swarm of bees (friendly), a large + & - g capability and a bubble canopy. The ability to see & avoid is different for them than us. Should they receive a "descend now.. increase rate" RA he could roll & pull in the wink of an eye. What he would then do on the subsequent RA from traffic 10,000' below would be interesting. He might also have the option to manoeuvre laterally, which we do not yet have.
Either way it's not apples & apples. I expect the military have more flexible SOP's than us. :hmm:

Herod

13th Nov 2016, 11:27

Guys. We've got to post 140 on this, and are still disputing it. FOLLOW THE RA. End of story, and rant.

ACMS

13th Nov 2016, 11:37

Yes, once again these rules have been written in blood and are there for a reason.

Sonny_Jim

13th Nov 2016, 16:41

Reading this thread has just scared the cr@p out of me.

West Coast

13th Nov 2016, 16:57

End of story

No, it's not. You fly into busy,one way in, same way out mountain airports and needlessly follow the RA on the aircraft you've seen for the past couple of miles, you're asking for trouble. Could you be seeing another aircraft, yes but the chances are greater the RA will introduce a threat than resolving one. This especially so when both are talking to the tower in Class D airspace. I've been in the situation where id have been put into a precarious position had I followed the RA, the other guy (which I've been on many an occasion) is now placed into a position of having to fly an emergency terrain extraction needlessly at places like KASE.

Few rules or conventions is so universal that you can say something is an absolute or "end of story" to use your words.

RAT 5

13th Nov 2016, 18:37

I hope this matter can be now put to bed, but.....anecdotes are just fun, sometimes. I was subject to the JFK guys 'pushing tin'. Approaching finals, No.5-ish, at 90 degrees and 210kts. I was asked to go to 230kts to slot in and establish on LOC. ATC never stopped talking. I was then given 'clearance to land'. (don't go there; it's been discussed at length). Meanwhile I can hear the guy behind me being asked to slow to 180kts - I assume to stretch it out behind me, a heavy. Meanwhile I'm still steaming in at 230kts and visual with all a/c ahead of me & the runway. I'm trying to get a word in & request to slow down to get flaps etc. out for landing. No chance. Johnny Carson on ATC is in full flow. I now get a TA on the a/c in front. He's slowing down. Soon that is going to evolve into an RA. Then what? That is going to be a climb, I hope, but I'm still at 12-15nm on the glide. I'm watching the range decrease, and, just before I start to get real twitchy, ATC give me 90 degrees right, 180 left, 90 right and I'm still No.5. No doubt there was an 'oops' moment in the radar pit. However, I always wonder what would have been the outcome if TA had become RA. There was no chance of collision; it was a closing speed thing and all I had to do was slow down; I had penetrated the bubble on the guy in front; except I was under ATC command. If I'd slowed down to maintain separation at the limit of the bubble it would have domino'd down finals behind me. So what, but under ATC we are 'trained' to follow orders.
It all worked out, but an interesting encounter of the 3rd kind.

ATC Watcher

13th Nov 2016, 20:38

RAT5 : There was no chance of collision
Then you will never get an RA.
The collision geographical model is very complex ,not many people really understand it 100% ( me included) but when TCAS works normally, you need to be on collision course to get an RA. In your JFK case, if you follow someone slightly slower it will just be a long TA...until you get very close of course, or below 1000ft AGL.

mrhooker

13th Nov 2016, 20:55

There are many fools flying after reading this thread.
ALWAYS FOLLOW RA'S

FullWings

14th Nov 2016, 08:06

I think the most important point, which keeps being stressed then ignored, is that THE RA MAY NOT BE CAUSED BY THE AIRCRAFT YOU CAN SEE.

In RAT 5’s example above, it would have been easy to fixate on the aircraft in front (not implying you were, RAT 5) especially if you were already getting a TA. When it turns into an RA it could be another aircraft attacking from the side that you weren’t previously aware of. I actually had this exact scenario happen at JFK on long final and it was VFR traffic that wasn’t talking to Kennedy...

His dudeness

14th Nov 2016, 08:16

Forgive my ignorance but my training has always taught me that TCAS RAs MUST be complied with.

Now skygods, I´m only a lowly Citation driver - I have been taught exactly this:

follow the RA.

HAVE I BEEN LIED TO ?

Yes or No, please.

H Peacock

14th Nov 2016, 10:14

How would any of you TCAS users have reacted in the same situation? Remember, only 2 aircraft within miles (you and the F-16), both visual, the F-16 flying VFR, you flying IFR in VMC conditions.

On the military hardware I flew (Global Express) if visual with traffic that we could see would shortly cause an RA, we would invariably go 'TA only'. We invariably did the same in our instrument pattern when you knew ATC-coordinated traffic was likely to result in an RA which would just spoil everyone's day.

If you're not going to follow an RA then perhaps you should have gone 'TA only' so 'his' TCAS then knows your TCAS is not going to be giving you a profile you're going to ignore! If you're going to keep the TCAS in TA/RA then you have to follow it!

ironbutt57

14th Nov 2016, 11:42

n the military hardware I flew (Global Express) if visual with traffic that we could see would shortly cause an RA, we would invariably go 'TA only'

strange concept..

Onceapilot

14th Nov 2016, 12:13

On the military hardware I flew (Global Express) if visual with traffic that we could see would shortly cause an RA, we would invariably go 'TA only'. We invariably did the same in our instrument pattern when you knew ATC-coordinated traffic was likely to result in an RA which would just spoil everyone's day.

If you're not going to follow an RA then perhaps you should have gone 'TA only' so 'his' TCAS then knows your TCAS is not going to be giving you a profile you're going to ignore! If you're going to keep the TCAS in TA/RA then you have to follow it!

H Peacock
Hi, you are going to have to explain under what regulations you followed these "proceedures"?:ooh:

Canute

14th Nov 2016, 13:15

The problem with just saying "In all cases follow the RA" is that the TCAS system only operates correctly if certain parameters are kept within. There is a reason that there are caveats.

Military aircraft doing very high rates of climb and descent for example are more than capable of confusing the system because it was not designed to cope with them.

OAP.

re your question to H Peacock.

Imagine for a second you are flying orbits/racetrack patterns over a dusty unpleasant country. Imagine further that you are in a stack of other aircraft all orbiting at various levels. Occasionally one of the smaller ones might suddenly dive or climb through your level. Under those circumstances, TA can be a good idea, as can ignoring RA. RA does not mean you are on a collision course at all, it merely means that another aircraft is going to encroach on a very large bubble with you at the centre. Military pilots are trained to be able to operate with other aircraft in that bubble, indeed that is the entire point of many of them.

peekay4

14th Nov 2016, 14:26

Military aircraft doing very high rates of climb and descent for example are more than capable of confusing the system because it was not designed to cope with them. ... RA does not mean you are on a collision course at all, it merely means that another aircraft is going to encroach on a very large bubble with you at the centre.

TCAS II advisories are inhibited for very high vertical rates (> 10,000 fpm). So a military aircraft climbing in excess of this threshold will never generate TAs or RAs.

Otherwise, TCAS computes what is known as the Closest Point of Approach (CPA). Version 7.0 introduced a filter called "Horizontal Miss Distance" (HMD). The HMD differs with altitude, but basically tracks another variable called DMOD which varies from 0.2nm at 2000 ft to 1.1nm at FL200 and above. Note that these values are considerably smaller than ATC separation minima.

TCAS also computes the time to the CPA, called tau. Above 10,000ft, the tau threshold for an RA is around 30 seconds.

So if you're in cruise level at FL360 and there's an intruding aircraft (military or otherwise) climbing from below at brisk rate (say at 8000 fpm), then an RA will be issued if the intruder is predicted to cross inside 1.1nm of you horizontally within about 30 seconds. That could be a 1nm "near miss", or a direct hit collision -- there isn't enough precision to know.

What TCAS can't measure is intention. Maybe that intruder, currently at FL280, will level off at FL320. In that case the RA would have been unnecessary. But perhaps it was cleared to FL400? You just don't know. That's why you always follow the RA.

Onceapilot

14th Nov 2016, 15:53

Canute
HP does not state that he was operating in Mil airspace or regulations. He needs to clarify if he is talking about operating in Civilian airspace? Also, I am not aware of exemptions within UK Civil or Military airport zones or areas for the random selection of TA ONLY to avoid RA in the instrument pattern?

Canute

14th Nov 2016, 16:30

OAP.
Military aircraft don't have to obey normal civilian rules just because they are in civilian airspace. I'm not suggesting that it is done casually, but there are many reasons for different rules.

PK as I'm sure you are aware from your name, RAs are triggered around military aircraft a lot. I operated a military type with TCAS, and to have obeyed RAs would have been dangerous on many occasions in theatre.

TA,

I quite agree. I was merely giving an example of why the caveats are there. In my opinion TCAS should be linked to autopilot in all civil aircraft.

TCAS is excellent at what it was designed to do, but it is a simple system and limited in scope. That is why there will always be the caveats with this current system.

Onceapilot

14th Nov 2016, 17:02

CANUTE.
Military aircraft don't have to obey normal civilian rules just because they are in civilian airspace.I think that you will find that UK Mil aircraft ARE generally required by the Air Staff to follow civilian rules and the ANO within civilian airspace. Military restricted areas, of various types, allow Mil aircraft to operate outside the ANO. Exemptions may apply to specific types and are applied through specific SOP and RTS.

Ian W

14th Nov 2016, 17:18

Not necessarily in Europe, if the military aircraft are flying under Operational Air Traffic (OAT) rules as opposed to General Air Traffic (GAT) who follow the civilian ANSP rules.

"
Operational Air Traffic (OAT)
Description

The term Operational Air Traffic (OAT) is applied in Europe to all flights which do not comply with the provisions stated for general air traffic (http://www.skybrary.aero/index.php/GAT) (GAT) and for which rules and procedures have been specified by appropriate national authorities. (EUROCONTROL EATM Glossary of Terms)
Most OAT flights are operated by military agencies."

Operational Air Traffic (OAT) - SKYbrary Aviation Safety (http://www.skybrary.aero/index.php/Operational_Air_Traffic_(OAT))

Canute

14th Nov 2016, 17:23

yes, generally, but only generally and I notice that you limit it to UK military. It is a choice, not a requirement.

But for example, most military pilots don't have a civil pilots license, medical or IR yet they bimble around in civil airspace.
Most/many military aircraft don't have anything even approaching the correct Nav/Comms fit.
Many are not even talking to the civil ATC.

Onceapilot

14th Nov 2016, 17:53

Ian W
OAT/GAT has little to do with it. UKMil TCAS proceedures closely mirror Civ but, will depend on what the Mil aircraft are tasked to do and what it says in their SOP and RTS. I am not going to talk about that.:)

Onceapilot

14th Nov 2016, 18:15

Canute
I go back to this from HP, On the military hardware I flew (Global Express) if visual with traffic that we could see would shortly cause an RA, we would invariably go 'TA only'. We invariably did the same in our instrument pattern when you knew ATC-coordinated traffic was likely to result in an RA which would just spoil everyone's day.

This cannot be SOP for all operation of the Global Express by UKMil.:ooh:

Ian W

14th Nov 2016, 18:48

H Peacock

14th Nov 2016, 21:07

OAP, the point I'm making is that if I knew I was in a situation where I'd no intention of following an RA, I'd go 'TA only'. Exactly as the designers of TCAS decreed and why they put a TA only option on the box! If you're not going to follow the RA (why?) you should be in TA only!

Now, A few examples of when I'd go TA only.

1. Airways transit to Southwold (TA/RA), descent into formation hold then flypast (TA only). Flypast complete, split & rtb (TA/RA)

2. Transit through CAS along a defined mil corridor with numerous other mil AC at similar alt (TA/RA). Faster mil aircraft closing to pass at same alt and less than 1nm, (TA only)

3. Visual circuit when routing downwind to Initials (TA only)

4. Recovering to Cranwell from complex sortie (TA/RA). Joining TACAN hold with numerous Tutors, KingAirs etc in vicinity (TA only)

5. Supersonic airliner loitering at 2000ft overhead Leuchars waiting 15 min for the Red Arrows to appear (TA/RA). A Tucano calls visual and asks to format in fighting wing on said airliner ( TA only)

framer

14th Nov 2016, 21:52

Recovering to Cranwell from complex sortie (TA/RA).
Would recovering to Cranwell from a simple sortie be TA only?

H Peacock

14th Nov 2016, 22:06

Nope. Unless practicing a max-rate descent, descending out of CAS was always TA/RA as was the recovery (joining the hold) until it got so busy with a mix of Visual and instrument traffic. If that traffic wasn't there, you could comfortably stay TA/RA throughout, but if it was there and a spritely Tutor got 'too close' the implication of a full RA could have been far more of an issue than simply 'seeing and avoiding'.

Of course if it got too busy you may have been better to have gone elsewhere!

Canute

15th Nov 2016, 06:00

OAP

Exactly how many different Glex SOP do you imagine the RAF have?

Capn Bloggs

15th Nov 2016, 07:35

Onceapilot

15th Nov 2016, 08:37

H Peacock
OAP, the point I'm making is that if I knew I was in a situation where I'd no intention of following an RA, I'd go 'TA only'. Exactly as the designers of TCAS decreed and why they put a TA only option on the box! If you're not going to follow the RA (why?) you should be in TA only!

Now, A few examples of when I'd go TA only.

1. Airways transit to Southwold (TA/RA), descent into formation hold then flypast (TA only). Flypast complete, split & rtb (TA/RA)

2. Transit through CAS along a defined mil corridor with numerous other mil AC at similar alt (TA/RA). Faster mil aircraft closing to pass at same alt and less than 1nm, (TA only)

3. Visual circuit when routing downwind to Initials (TA only)

4. Recovering to Cranwell from complex sortie (TA/RA). Joining TACAN hold with numerous Tutors, KingAirs etc in vicinity (TA only)

5. Supersonic airliner loitering at 2000ft overhead Leuchars waiting 15 min for the Red Arrows to appear (TA/RA). A Tucano calls visual and asks to format in fighting wing on said airliner ( TA only)

Thanks for those points. The question remains, do your examples of "when I would use TA ONLY" reflect a coherent RAF strategy of TCAS use that is reflected in your Orders, SOP and Aircraft manuals or, are you making your own choice when to use TA/RA? Here is another question, would you do the same flying into Brize?

Canute

15th Nov 2016, 08:38

At least one other that requires TCAS to be operated in TA/RA at all times in airspace frequented by fare-paying passengers! All that stuff might be OK flying in amoungst his RAF jet jockey mates but when he's mixing it with airliners/other civvies, he can use the TCAS properly: giving and coordinating RAs.

TA is a correct use of TCAS.

It is also more than the majority of military aircraft that "mix it with airliners" have.

TCAS works perfectly well with one aircraft in TA mode. just as it does against transponding aircraft without TCAS

Onceapilot

15th Nov 2016, 08:47

Canute

Exactly how many different Glex SOP do you imagine the RAF have?
I do not know. However, there seems to be something worth exploring here, not to criticise specific Mil use of TCAS but, to inform the majority of airspace users.

H Peacock

15th Nov 2016, 09:26

Thanks for those points. The question remains, do your examples of "when I would use TA ONLY" reflect a coherent RAF strategy of TCAS use that is reflected in your Orders, SOP and Aircraft manuals or, are you making your own choice when to use TA/RA? Here is another question, would you do the same flying into Brize?

I'm not sure the RAF has a coherent strategy on TCAS. I know of some guys who'll not get airborne without it! It's a great tool to have, but like so many other bits of kit we have, you need to use common sense and airmanship. I know the latter is being steadily removed by the desire to have all-encompassing SOPs.

You're probably guilty of going off-thread here so suggest you open one elsewhere if you want to pursue a discussion on SOPs!

As for Brize - Yep, led a 3 ship through the zone, so my PF's Airmanship decided to go TA only. A very busy piece of airspace that day as multiple formations split up, so trusted ATC and my fellow aviators to do their jobs as briefed. If we'd had an RA I very much doubt we'd follow it, therefore TA only.

Canute

15th Nov 2016, 10:24

OAP

The problem with SOPs is that whilst they are perfect for civil operations, ie they should follow a script where ideally nothing unusual ever happens etc, the growth/expansion of SOPs hinders flexibility in military operations which by their very nature should not follow a script and ideally should be different every time..

Capn Bloggs

15th Nov 2016, 10:30

TCAS works perfectly well with one aircraft in TA mode. just as it does against transponding aircraft without TCAS
Yep, the coordinated RAs work well...

Square Bear

15th Nov 2016, 11:19

[QUOTE]OAP, the point I'm making is that if I knew I was in a situation where I'd no intention of following an RA, I'd go 'TA only'. Exactly as the designers of TCAS decreed and why they put a TA only option on the box! If you're not going to follow the RA (why?) you should be in TA on/QUOTE]

H PEACOCK, maybe you don't want to follow the RA instructions, but the other guy and his hundred plus pax might...

Not sure how it could be justified to be simply a one sided decision.

deltahotel

15th Nov 2016, 11:25

TCAS in the massively dynamic military environment (eg the environs of Cranwell's circuit) would be an amazing SA tool, but useless and possibly dangerous in RA. In the slightly more benign environment of civ CAS, airways etc for which it was really designed please please please follow the RA.We lost an aircraft at Uberlingen because our guys did and the other bunch didn't. The manoeuvre is simple, gentle and over very quickly and is there for when every other traffic separation method has failed for whatever reason.

H Peacock

15th Nov 2016, 11:51

H PEACOCK, maybe you don't want to follow the RA instructions, but the other guy and his hundred plus pax might...

Oh dear Square Bear, I'm not sure you fully understand how TCAS works. If both aircraft are operating in TA/RA, have a conflict and follow their respective RAs, all should be well. One of the TCASs probably initiated its RA first, telling its pilot where to go and also through mode S telling the other aircraft's TCAS what it's doing. This second aircraft's TCAS now knows what the first aircraft is doing/going to do and issues a suitable RA based on the dynamics of the situation and what it understands the profile the first aircraft is now following. If the pilot of the first aircraft has decided to ignore his TCAS then the second TCAS won't know until it detects that the dynamics of the situation are deteriorating rather than improving. It may then have to amend its proposed RA. All very uncomfortable and possible too late to avoid a collision.

So, if the first aircraft has a reason that it's not going to be flying any RA (as previously stated, it needs to have a valid reason) by selecting his TCAS to TA-only he tells the second TCAS it can do as it sees fit from the outset to produce a more timely RA. This avoids the crucial delay caused by having to detect that the first aircraft is not following its RA.

The second aircraft operating in TA/RA will always get it's RA from the first aircraft, but it gets significantly more time to produce a better outcome. Ie, you don't need both aircraft to be operating in TA/RA to generate an RA in the second aircraft. It's important that you understand that.

The point I'm trying to make (obviously not clearly enough for some) is that ignoring an RA is significantly more dangerous than that aircraft operating in TA-only. The decision of if/when to go TA-only is complex and I suspect not something many commercial-only operators would have thought about. However, had I not operated TA only in the examples quoted in my earlier thread, then I simply could not have achieved the mission objective!

Onceapilot

15th Nov 2016, 15:46

Well, if the present use of TCAS in parts of the RAF is as HP states, then I am surprised.:oh: Any incident involving TCAS use will look for adherance to laid down proceedures and best practice. Can anyone else who knows comment? Last time that I used Brize, the airfield and zone expected the use of standard TCAS proceedures by aircraft so equipped.

H Peacock

15th Nov 2016, 16:38

OAP

Not sure how long ago you were a pilot, and I strongly suspect from your comments you have very little understanding of the world of military aviation, but just because you don't understand a concept, please try to avoid telling the world it's wrong!

You clearly can't comprehend the reasons stated for using TCAS in TA-only. I can do no more than tell you that many RAF aircraft fitted with TCAS will at times be required to fly close enough to other squawking aircraft which would cause, when operating in TA/RA, an RA to occur; they'd be forced to follow an RA that would move them away from another aeroplane that needs to be close!

It's not appropriate to divulge many of the numerous tactical situations where an 'inadvertent' RA could occur, but for a peacetime one have a google of 'Queens Birthday Flypast'. It may even be on YouTube. Lots of aeroplanes all quite close to each other flying through the middle of the London TMA. Now tell me how that would work if all the heavies fitted with TCAS flew in TA/RA? I believe one year we even took the entire flypast through the Brize overhead. I don't recall ATC asking or even expecting us to be in TA/RA!

Onceapilot

15th Nov 2016, 18:22

Please don't rant HP.:rolleyes: I do hope that your description of "TCAS in the RAF-use it how you wish" is not reality in your corner of the Air Force? If it is, someone needs to get a grip and write you some Orders!:eek: No more from me, Thanks.

Capn Bloggs

15th Nov 2016, 21:28

It's not appropriate to divulge many of the numerous tactical situations where an 'inadvertent' RA could occur
Tickets...

Lots of aeroplanes all quite close to each other flying through the middle of the London TMA. Now tell me how that would work if all the heavies fitted with TCAS flew in TA/RA?
Yep, TA it should be. "Traffic Traffic Traffic Traffic Traffic" "Derek, tell that thing to shut up!" "I can't Nigel, as you told me to put it in TA!" "Orright Nigel, tell the king to move away from us a bit!"

Max Angle

15th Nov 2016, 22:41

is that ignoring an RA is significantly more dangerous than that aircraft operating in TA-only.Spot on, can't believe so many people are having trouble with that concept. Pretty obvious that there are situations in the military world where you would be unable to follow an RA, civil aircraft set TA in engine failure cases for the same reason. As you rightly point out setting TA means you are still fully interoperable with other TCAS equipped aircraft which can generate their own RAs if required.

framer

16th Nov 2016, 00:19

There will be orders written down. Whether or not individual squadrons are adhering to them is largely dependent upon leadership within and above the squadron. A good example of how a squadron specific 'we don't have to follow the rules' culture evolves to a dangerous level is the RNZAF ANZAC day Iroquois crash of 2010.
If anyone reading this is leading a squadron, you need to know the orders, understand your responsibilities to your men, women, and the nation, ( in peacetime and at war), then have the courage to enforce the orders that have been written. It is surprising to me how few 'military leaders' have this fortitude and simply run the show like the last guy did ( ie perpetuate what ever culture they inherited).