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Kestrel Mayday (TCAS discussion)

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Kestrel Mayday (TCAS discussion)

Old 17th Mar 2003, 14:19
  #61 (permalink)  
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To pursue the matter of TCAS useability with an engine failure, here's what Gulfstream told us on my (recent) G5 initial:
TCAS is fed with "standard" performance specs for the airplane you are flying, ALWAYS assuming all-engine. When in conflict with another airplane, both TCAS also "exchange" their aircraft type. Due to the very high performance of the G5, and if a resolution advisory occurs, the G5 will get the "CLIMB CLIMB" end of the deal.
Accordingly, one item on the "Engine failure in flight" checklists is the switching of the TCAS to "TA only". This will not only prevent our own aircraft from displaying RA's outside of the envelope, but it seems (instructor said so...) that the box will actually transmit the fact that we are in "TA only" mode. What I don't know is how that transmission could or should affect the other party in the conflict...
Anybody know more about the intricacies of TCAS in these situations?
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Old 17th Mar 2003, 15:46
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With TA only selected the "other" aircraft assumes worst case and gives instructions to climb or descend depending on altitude, ROD or ROC etc to deconflict. After an engine failure TA Only is a good airmanship decision - of course there may be situations that would not be suitable but i wont labour the point here. Suffice to say that if you don't you may get a "Climb Climb" RA which you may not be able to correctly follow.
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Old 17th Mar 2003, 18:20
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Faustino; first, lets get the legal wrangling out of the way. I asked a real, practising lawyer for a definition of Law, Statutory Instruments etc. Here is the reply

"Generally speaking:

- the term 'Law' refers to all forms of law, including legislation
passed by parliament (Acts), statutory rules (which derive their power
from legislation), common law (laws that derive their power from
precedent and have been passed down through the ages, eg negligence),
order-in-council, constitutional law, by-laws etc etc.

- the term 'legislation' refers to the Act itself. For example, the
Air Navigation Act may empower a particular office-holder to make
certain rules. In this case, the Act is the legislation and the rules
are statutory instruments."

So TCAS is addressed in 'Law', by Statutory Instruments. See ealier posts.

Back to the main problem:
TCAS RAs and the situations when they are required, are time critical. You must act on an RA within seconds for it to be effective (I believe 5 seconds is the standard?). When you make statements confirming that you may or may not act upon an RA, you are condemning the system to failure. RAs require an almost blind obedience. You have already had 45 seconds (the TA) to assess the threat, get it visual, seek ATC guidance, whatever. An RA means it is out of the controllers' hands now. As I hope everyone is aware, the system is flawed. But if everyone is not on the same page vis ground rules ie. everyone follows the RA, then we are setting ourselves up for another Bodensee. And that truly is a tragedy.

ps. if you think some blame apportioning at Bodensee will help your arguments- well, what can I say? Why don't we think in terms of learning and fixing, instead of blaming?
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Old 17th Mar 2003, 19:56
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ferris, yes, let's stop wrangling. We disagree about the legal position on TCAS. Many 'experts' I talk to agree with my view - that's how I arrived at my view in the first place! But, let's not fall out over it!

Now to the nitty-gritty: You will not get a guaranteed 45 second TA, especially with v7.0 - it may be much shorter. See Prof. Peter Ladkin's paper on RVSM vs TCAS and the Safety Case for details of how v7.0 may be a step backwards.

You mention 'learning and fixing, instead of blaming'. I am wholeheartedly behind you, and my day-to-day work centres on just this!!!

My point is, that until legislation/law/SI/whatever you want does properly take account of TCAS, then it is at worst a loaded gun with someone else's finger on the trigger.

It is at best an elastoplast, an ambulance at the bottom of a cliff, an unreliable last line of defence. The whole industry has tackled TCAS from the wrong angle. That's why Bodensee happened.

Please, let's all try to keep the safety ball rolling, with the best genuine intention of ensuring the last mid-air was the last mid-air.

Sadly, it won't be...
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Old 17th Mar 2003, 21:21
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So what is your proposed solution?
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Old 19th Mar 2003, 10:14
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You would be surprised how many ATCers dont know didly about a/c. Plenty dont know that a twin cant maintain cruising level with one engine out.
ATC knowledge about aircraft performance is rudamentary. Unfortunately any background lectures on aeronautics were abandoned long ago. We really should know more about aircraft performance as it is constantly changing. For years ATCOs were encouraged to take 2 familiarisation flights a year and get real line cockpit experience. Then we were privatised and guess what ... we were short of money so the first thing to go was this sort of "unnecessary" expense.

Still, in 30 years I have known hundreds of ATCOs doing their best to gain knowledge by going on these flights. Very few pilots have shown an interest in learning the ATC side of things which is why you get the sort of comments made by Finbar which are made through ignorance of the real story.

limaeco An excellent post. We appreciate what you were doing.

Nice to see PPrune returning to some interesting professional points.
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Old 19th Mar 2003, 13:12
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Very entertaining discussion. A few points from my side of the world, that is Texas;

Whether the pilot says "Pan", "Mayday", or "Blueberry"; if I know the aircraft has lost an engine, ATC will treat that aircraft as an emergency, unless there's a very good reason known to us not to. Obviously, we're going to be taking clues from the crew's requests and tone on the radio as to how much Immediate assistance is required.

As for the remarks about controllers not knowing much about aircraft performance; while It's obviously been more difficult and expensive to obtain pilot ratings/experience in other parts of the world, I presently work with, or have worked with:

Retired DC-4 thru 727 Captains
Decorated Air Force Pilots from WWII thru Vietnam and later.
Decorated Vietnam era Army Helo pilots
Controllers with type ratings in Lr-25, Hawker 125, etc.

We currently have about six Flight Instructors at my facility, and at least another half dozen with FAA Private/Commercial ratings.

The above list comes from just two medium sized Terminal facilities. Were you to canvas a Center, with 400 some-odd employees, God knows how many former/furloughed airline and corporate pilots you'd find.

And I myself am a CFIIMEI with Corporate experience (albeit many years ago) on the MU-2.

The truth is, none of us have training in mental telepathy, as someone noted. In an Emergency, tell us what you need, and we'll do our best to see you get it.
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Old 19th Mar 2003, 21:19
  #68 (permalink)  
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This is a great thread, Itís got me thinking!

Back to the 7700 argument,

We (bus drivers) all spend most of our time in the sim practising engine failures on approach or on departure when 7700 is pointless as control know who and where we are, and in the case of departure have just given us a code and are waiting for us to call them to verify our altitude. It is assumed that an engine failure on approach or departure are the most difficult to deal with and if we can handle that, we can handle one in the cruise. This is true BUT there are many new factors in an engine failure in the cruise that are not considered for approach or departure, one of which is 7700.

The ATC guys have been quiet on this one. Is it true that you are filtered and that 7700 shows up on all of your screens? Do you expect us to change to 7700? Do you want us to? I donít know what our SOP is for 7700 use. Iíll look it up now (man I hate those binders!)

I do know our SOPs say engine failure = Maday. No decision to be made. Many of you were right in saying that you have suffered a 50% power loss, BUT you have also lost 80-90% of your performance (time to pull out those flight manuals again lads!). That kind of performance degradation is a Maday call, every time. You ARE coming down, I wouldnít even downgrade to a Pan on approach, what If you miss the approach? Itís a long slow climb away from the ground!

Itís been great getting the ATC input here Ė Keep it coming! This is exactly why we need cross over training, we need to understand each otherís jobs. We spend all day talking to each other, and we need a good understanding of what the other does. Why is a controller allowed to tell 10-13 aircraft what to do when heís on the ground, but suddenly becomes a security risk and a danger to safety if he sits in the jumpseat?

Iím not trying to re-open this debate, but is the jumpseat going to become somewhere to keep our emergency sandwiches and coffee for those occasions when we piss the Cabin Crew off and they ignore our calls for sustenance?
Old 19th Mar 2003, 22:40
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In London airspace currently controlled from Swanwick, some sectors are permitted to operate with filters, but the majority aren't. It is certainly true that by selecting 7700 you will break through ALL filters and be displayed with a red alternating yellow flashing box around the Datablock associated with the return. There is no mistaking an emergency squalk. Also by selecting an emergency squalk, an alarm bell sounds inside the Diversion/Distress cell at West Drayton monitoring 121.50MHz. This however differs in Terminal Control still at West Drayton, as the Datablock loses its callsign information for it to be replaced by 7700, but still it breaks through the filters.

As a controller receiving such a 'Mayday' call as this one, I will automatically in first reply say, 'Roger Mayday, when able squalk 7700'. Every time. If you ever think you are too busy to call ATC, then definately just select it ASAP so at least we know you have a problem. It will certainly lead us to instantly calling you and imposing an RT silence, but what else would you expect? I highly advise against this practice though, and should NEVER be too busy to call ATC, there is just too much going on out there for it to be safe not to.
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Old 20th Mar 2003, 18:08
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Given the close interaction and interdependence I guess I'd sort of automatically assumed that ATCO's and pilots had some sort of cross-training. Theory, ATC visits, jump-seats, sim stuff and so on for both.

As it emerges, you don't seem to much and from the sound of it, it would help a lot with understanding, cooperation, tempers and, dare I say it, safety.

So why isn't there more X training?

[Modbod - should I re-ask this in the Questions forum?]
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Old 20th Mar 2003, 18:53
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TCAS or ATC.....

If its to the point of a RA, likely my primary means of seperation, eyeballs and ATC have failed. Its now time to to listen to the box which is not under the stress a controller might be at that point. By that point the controller is no longer planning, just reacting.

To mayday, or not to mayday...

Depends on type of engine failure, associated failures, location, atmospheric conditions, weight and numerous other considerations. Numerous aircraft have certain engine out procedures in the abnormals and not the emergency sections of the books.
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Old 20th Mar 2003, 20:26
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I personally experienced 2 TA's, on one I've never seen the intruder despite looking out and not IMC and on the second one we saw the intruder at the very last time (it was a light piston-twin) and it was also IMC,

these to say that:

1- According SOP's we must follow any TA

2- It is nice to look outside, but as you know, sometimes it's very hard to pick an aircraft doing the approach just in front of you!

3- It is working only if every body do the same ( look at Bodensee)

Mayday vs Pan Pan:

When dealing with a threatening failure, engine, flight control, structural damage, smoke-fire) one is flying, navigating and radioing, the other is doing the MC's, then we should return to normal loop (extended) and assess the situation? right, then you choose to decalre an emergency perhaps with the mandatory reports, 7700 and TA only, so it is likely that you started to descend a bit already! Not easy when under pressure to think at all those things together and not missing a part...

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Old 20th Mar 2003, 21:53
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My company's SOP's state that an engine failure is definitely a Mayday Call. That is for many reasons some of which being: Unable to maintain altitude, what happens if you lose the other engine as well etc. For the Bus drivers, don't forget the RED LAND ASAP memo on the lower right corner of the E/WDisplay.

When it comes to TCAS RA's while you are on single engine, my company's QRH in the engine failure page, says to select the TCAS selector to TA's ONLY, so that not to be given RA's that you may not be able to follow.

I also believe that instead of starting Airbus Vs Boeing arguments it would be better to say well done to the guys that landed the plane safely and saved lives.
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Old 21st Mar 2003, 17:26
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Is there anyone out there willing to step forward and say that their SOPs, local laws (or the widely held interpretation of said laws, either by unions, pilot bodies, personal opinions), or beliefs are to follow an ATC instruction in contravention of an RA?
Please add as much about where and for whom you work as you feel comfortable with.

This is not a slag-you-off session. Just trying to gauge how much variety/confusion really exists out there.

ps. not all controllers are ill-informed halfwits when it comes to a/c.

pps. a/c can also mean air-conditioning
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Old 21st Mar 2003, 18:18
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Can the controller declare an emergency too? I overheard an exchange where a water cooled light piston had dumped it's coolant over the side over mountainous terrain. The VFR pilot was not keen to say MAYDAY or even PAN (which is not even taught in the USA). The pilot was obviously not a "professional", whatever that means , and maybe that was very relevant to what happened.

The controller eventually said something to the effect of "XXX Approach is declaring an emergency. NXXXX squawk 7700, cleared into the XXX Class B, if able maintain altitude and turn right heading 270, contact me on xxx.xx, etc etc etc"

So although he could not force the pilot to say MAYDAY, the controller was able to escalate things to "emergency" and get the ball rolling so he could make things happen. This was in the States and the plane landed safely.
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Old 21st Mar 2003, 21:46
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If you have an engine failure there is no doubt you should declare a Mayday in my opinion, I would also squawk 7700 when time allows, I want to make sure I get all the help I can!

The USA is not the only country that does not recognise PAN, try using it in Spain and you will be met with a stunned silence or asked to say again! My view is if you need to declare a PAN outside UK airspace say Mayday and explain later.

With regard to TCAS being set to TA after an engine failure the Airbus FCOM 3 drill ďafter ENG 1(2) failureĒ instructs you to select TA. I canít recall what the Boeing or MD manuals say and they are tucked in the loft somewhere. I would say setting TA after an engine failure seems like good airmanship to me.

As for ATC not understanding performance that may be true to some extent but as has been pointed out many controllers are also pilots. That said I canít see why it should cost NATS any money to let their controllers fly on the jump seat. After all most of the larger UK airlines are part owners of NATS so in a way UK controllers are to some degree company employees! Certainly I have taken controllers on the jump seat in the past and my company has not charged NATS for these familiarization flights.

I have long felt it would be worth investigating getting controllers in the Simulator for day two of an LPC/OPC; we do it with cabin crew. I certainly found visits to West Drayton and Prestwick very useful, especially the hour I spent on the ATC simulator, three-dimensional chess! I found the experience gave me an even greater respect for the job UK controllers do.

Last edited by kinsman; 21st Mar 2003 at 22:18.
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Old 22nd Mar 2003, 02:41
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In the U.S., the crew, the controller, OR the Operator may declare an emergency.

Anyway, most of the firefighters I know say they rather enjoy the practice of setting up on station alongside the runways;

(Unless there's a good football game on of course....)
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