TCAS RAs -hassle and paperwork

[pilot1957]

Dear gentlemen and lady ATCOs in the UK and Eurocontrol region
I would appreciate some help and opinions.

I am trying to educate and encourage my colleagues to consider reducing their ROC/D so that it is below 1500 fpm with 1000 ft to go for all levels off. At present we are only required to do so by company procedures if there is traffic to affect.
This is leading to RAs solely due to the continued high rate as perhaps crew forget to check the TCAS display for other traffic, or the TCAS display has not initially shown it.
This can cause concern for the other a/c and reports to be written for those involved.If these RAs can be reduced it will reduce angst and stress for crew of both a/c.
To support my case further I would be interested to know how much hassle these ROC/D nuisance RAs cause controllers themselves. Does it waste a great deal of time with paperwork etc afterwards?
Your help would be much appreciated.

[Radar Contact Lost]

Not a huge amount of paperwork on our end. We have to fill in an MOR which takes about 20 minutes. It's a massive annoyance though and then has to be investigated at our side through the investigation team. Not sure how long it takes them but it involves them pulling the radar tapes and RT to look at what happened.

At the time it can cause our hearts to skip a beat as we try and work out what just happened when we're working normally and suddenly get a told by an aircraft that they have a TCAS RA.

[HEATHROW DIRECTOR]

And.... the controller is suspended pending the outcome of the investigation.

[BOAC]

pilot1957 - apart from the 'hassle' for controllers and crews of an RA, it makes sense for passenger comfort. Perhaps your company should insist on it at all times? It is no hardship.

[FlightDetent]

pilot1975: I think your company has it right. But that's a different discussion topic and I do not want to hijack your thread.

Meanwhile, to reduce the stress and paperwork of ATCOs if a "nuissance" 1000ft level-off RA is issued, some guidance is provided in PANS-OPS.

Eurocontrol's ACAS Bulletin no. 10:
New ICAO RA reporting proceduresOn 22 November 2007 changes to ICAO PANS-OPS Doc 8168, PANS-ATM Doc 4444, and PANS-ABC Doc 8400 became effective. Now, only those RAs that require a deviation from ATC clearance or instruction need to be reported. The new phraseology is:��“TCAS RA”(pronounced “TEE-CAS-AR-AY”) My bolding.

Cheers,
FD.

[EastofKoksy]

Anything that reduces false alarm TCAS RAs is welcome. They are VERY distracting.

[TC_Ukraine]

just a few weeks ago: DLH descended FL330, CSA climbed FL 320. Both got traffic info, reduced rate to 500ft/min when approached to cleared level and.....got TCAS RA.

[Jwscud]

Pilot 1957 - it is a requirement to limit RoC to 1500fpm in the last 1000' of a climb/descent in RVSM airspace. I shall dig out the reference for you later on today.

[good egg]

While the OP was talking about the en-route environment, with a hint regarding an unwritten(?) "pilot responsibility" to reduce nuisance RAs, there are also ways of reducing nuisance RAs within CTRs - particularly Class D (my favourite!).

Regardless of who is providing the ATC service (tower or approach), separation between VFR and IFR in Class D can be reduced - in fact there is no "standard separation" - providing traffic information is passed.

In Class D an ATCO can, legally, clear a VFR aircraft to operate in very, very close proximity with IFR departures/arrivals. However, given "duty of care", it is unlikely (I hope/think!) that an ATCO would provide an "unsafe" clearance - in terms of collision risk.

I understand (feel free to correct me!) that there is a cut-off on departure/arrival - let's say around 1000ft AGL - below which TCAS RAs are suppressed and appear as TAs. Above that height, and still very much within the critical phase of flight, TCAS RAs will occur if the proximity of other flights is a concern.

I've worked in en-route/approach. Within those areas I worked with quite a few tools(!), including STCA (Short Term Collision Alert) which, if we look at parameters, is not dissimilar to TCAS RAs.

As ATCOs we should, wherever possible, reduce the risk of nuisance TCAS RAs/STCAs by use of "defensive controlling techniques". E.g. en-route we might apply a 2000ft separation between aircraft climbing/descending on similar/converging tracks....similarly at, or near, aerodromes we can apply a degree of common sense when issuing clearances to remove the need for flight crew to take evasive action.

Don't get me wrong, we can't apply every defensive technique every time (sometimes there will be over-riding factors....sector agreements, silent handover agreed levels, minimum safe altitudes, fair and equitable use of airspace, etc....but this should be a team effort by all those concerned, be it ATC or pilots (en-route, TMA, approach, tower, IFR or VFR).

If we can reduce "nuisance" RAs by working together then when it really matters everyone realises the importance of following them :)

[12right]

Interesting thread. Yesterday I was involved in a discussion involving commercial pilots and controllers who were debating the reduction in applied rates within the last 1000 feet due the RA situation. Some controllers were saying that at times rates are required for sep purposes or to meet airspace constraints and that they expected the instruction to be followed unless advised differently. Some pilots were suggesting that they would comply and others not due company instructions. Another operator suggested that in fact they would reduce to less than 1000 in the last 1000 to avoid a TA also. The fact that there was debate at all suggested that if sep or airspace constraints were the reason for the application of rates in excess of 1500 fpm then another standard increased vertical or lateral would be the best - thoughts :)

[FlightDetent]

just a few weeks ago: DLH descended FL330, CSA climbed FL 320. Both got traffic info, reduced rate to 500ft/min when approached to cleared level and.....got TCAS RA.
Please elaborate. Because what you say so far is impossible to exist, given the present algorithms.

FD.

[TC_Ukraine]

FlightDetent, just telling what i saw on playback.

[Over+Out]

If aircraft are going to be close, I just instruct them to reduce ROC/ROD. As a result, I have had very few if any RA's in this phase of flight.

[FlightDetent]

FlightDetent, just telling what i saw on playback.
Tell us more, please.. Because the techical papers have all this CPA stuff, with 35/45 sec limit to issue RA. If the combined rate of closure would be 1000 fpm, the RA would go no sooner than 750 feet separation.

FD.

[Bigears]

Jwscud,
...it is a requirement to limit RoC to 1500fpm in the last 1000' of a climb/descent in RVSM airspace. I shall dig out the reference for you later on today...

Let me save you the hassle...

UK AIP ENR page 1.1-13 (para 3.2.2.3.1)
"...Aircraft when first approaching a cleared flight level and/or when changing flight level in Controlled Airspace should ensure that the vertical closure
speed is not excessive. It is considered that, with about 1500 ft to go to a cleared level, vertical speed should be reduced to a maximum of 1500 ft per minute and ideally to between 1000 ft per minute and 500 ft per minute..."
This is repeated in NAT Doc 007, Chapter 9 (RVSM FLIGHT IN MNPS AIRSPACE) virtually word for word.

ICAO Doc. 8168, part VIII, para. 3.3
"Pilots should use appropriate procedures by which an aeroplane climbing or descending to an assigned altitude or flight level, especially with an autopilot engaged, may do so at a rate less than 8 m/s (or 1 500 ft/min) throughout the last 300 m (or 1 000 ft) of climb or descent to the assigned altitude or flight level when the pilot is made aware of another aircraft at or approaching an adjacent altitude or flight level, unless otherwise instructed by ATC. These procedures are intended to avoid unnecessary airborne collision avoidance system (ACAS II) resolution advisories in aircraft at or approaching adjacent altitudes or flight levels. For commercial operations, these procedures should be specified by the operator..."

my embolding (if thats the right word!).

The only <requirement> that I am aware of is from operators own SOP's (should it be specified), but I am willing to be corrected.


pilot1957,
Are you a FSO? Some suggestions...
For every RA, ask the crew were they aware of other traffic and if so, did they consider reducing their RoC/RoD.
Write a piece in your flight safety magazine to raise awareness.


Flightdetent,
As you may be aware, the UK has several differences to elsewhere.
One of these is that "All ACAS RAs should be reported, regardless of the cause" (CAP382, Mandatory Occurrence Reporting Scheme).

[fellman]

This issue was the subject of an ACAS Bulletin (No. 15 - "Not so fast...") published by EUROCONTROL.
www.skybrary.aero/bookshelf/books/1804.pdf (http://www.skybrary.aero/bookshelf/books/1804.pdf)

[FlightDetent]

Bigears
I am aware of UK differences, but no longer current on the content. I used to be quite fond of those, as in my opinion they showed a good understanding of ATC to flightdeck work relationsip.
Historically, when I used to operate in your airspace, I did well with 3rd party material (Jeppesen) and CAP 413. What you say is indeed news to me, and I already put CAP382 on my to-learn list. Thank you!

fellman The problem with Bulletin no.15 is - from my point of view - that it conveniently omits certain sentences from regulatory guidance. Exactly the one provided in Bigears' quote: when the pilot is made aware of another aircraft at or approaching an adjacent altitude or flight level

Respectfully,
FD.

[pilot1957]

Gentlemen and lady controllers plus other contributors thank you. Your thoughts did indeed contribute to the information presented to my company safety committee. Many others gave of their time too and it's nice to think that we can act together to try improve things.

Readers may be interested of something I came across during the research. To try reduce nuisance RAs one major European airline recommends in their OM A to reduce to 1000 fpm @ 1000 ft to go for all level offs. As a technique to achieve this pilots normally reduce to 2000 fpm @ 2000 ft to go. Their assessment of the effect of this over a few years is to reduce these type of nuisance/high rate RAs by more than 90%.

Regards
Pilot1957