View Full Version : When Is A Near Miss NOT A Near Miss??

19th Dec 2003, 04:30
Answer:- When you change the system. :rolleyes:

It is now claimed that the near miss by the Virgin Blue B737 near Melbourne recently was NOT actually a near miss.

It apparently cannot be declared a near miss under the new system, because under the new system there are NO figures laid down for how close a near miss is.

Under the old system it would have apparently been called a near miss.

So, obviously the new system IS much safer, as there will not be any "official" near misses.

Reminds me of "Yes Minister/Yes Prime Minister", you can use figures and statistics to prove whatever you want. :(

19th Dec 2003, 04:41
90% of all people know that, Kent. :}

19th Dec 2003, 05:16
Very good point lame.

When should a near miss be determined to be a near miss?

Why should we even take account of "near misses" since they are not system breakdowns, unless of course you figure that being able to see another aircraft is a system failure. Particularly when you define a near miss as being within 5 miles with less than 1000ft vertical separation.

Is it not irrelevant to consider some very generous arbitrary figure beyond which one is considered to be safe? How does one manage to travel along the highway with this concept firmly implanted upon one's mind?

Perhaps the problem is that under the old system the concept of safety was a bit too academic and not enough common sense, a bit too restrictive without a corresponding safety benefit.

Strange to think that a more restrictive system could actually be less efficient and safe isn't it. Nevertheless, it is true, and it is embodied in the Air Force definition of airmanship, "The safe and efficient operation of an aircraft, both in the air and on the ground."

Notice that neither safety or efficiency are given emphasis. In fact, safety and efficiency are complimentary. The reason why that is true is related to human factors. And since you are no doubt fully aware of human behaviour patterns, I am sure you'll be able to understand why it is so.

In fact, it was more like Yes Minister when the BASI report was used to justify ATC and permit the absolution of responsibility by airline pilots to see and avoid other aircraft. The NAS actually seeks to reduce the bureaucratic control of pilots by ATC and hand back responsibility for separation while in VMC to the pilots.

I find it hard to understand why anyone would not be willing to accept more responsibility if it also allowed them greater flexibility and efficiency, unless of course you couldn't care less about efficiency, just your own well-being. But that couldn't be right, could it?

Life's a bitch, then you fly!

19th Dec 2003, 05:50
Saw the Minister on TV the other night, I mean the real Minister not Jim Hacker ;) , and he explained it thus.

He said he drives every day on highways where he is only metres away from semi trailers passing him in the opposite direction at 100 kph. Does this mean that every one of these events is a near miss?

So I guess his logic is B737s and light Aircraft can pass within metres of each other, without everyone calling it a near miss? :rolleyes:

I just pray to (insert here applicable God) that nothing worse happens.

19th Dec 2003, 05:52
The problem lies not with the responsible VFR pilot,but with the idiot who will not be tuned to the right frequency and who does not have a operable transponder.Remember that it only takes one of these to cause the ultimate too near a miss.

Going Boeing
19th Dec 2003, 05:57
The term "near miss" doesn't quite make sense in that a miss is a miss irrespective on how close it is - perhaps a better term is a "near hit"or "near collision".

I agree with you LAME in that politicians and public servants will redefine "terms" just to make the statistics look the way they want them to look. GB

19th Dec 2003, 06:05
I guess they work on the old saying, (I think it goes), "a miss is as good as a mile".

However, you are right literally I guess. ;)

Whether it be Aircraft or semi trailers, an accident/collision (God forbid) would be a near miss (because they nearly missed).

What we are talking about is a miss, and as you said, should really be called something else, a near collision, or near accident.

19th Dec 2003, 07:16
Yes but perhaps they are trying to differentiate between just a miss (say, more than 0.3NM) from a near miss, where the pilots don't know how they didn't collide.

i.e. when they are close to each other then they are near each other but they still miss. :hmm:

My $1/50.

19th Dec 2003, 08:22

Makes sense, but the ATSB use 'near collision' in their incident investigations... 'near miss' is a media term that everyone seems to enjoy using these days.

48.5% of statistics are made up anyway!!

Next Generation
19th Dec 2003, 19:26
The next thing you know, the pilots involved in this incident will be charged with illegal formation flying !!!!!!!!!!!

19th Dec 2003, 19:58
Somewhere I remember reading that a TCAS RA in the USA should be reported to ATC as a 'Near Mid Air Collision' or 'NMAC'. Now, if we are going to use this system because it's what the Yanks, use, perhaps we should be using their conventions as well. That means, if the DJ pilots had an RA, they had a 'NMAC'.

Stick THAT in your pipe Messers Anderson, Smith et al.

20th Dec 2003, 15:21
The Aviation Safety Division of the Transportation Safety Institute of the Federal Aviation Administration of the US Department of Transportation defines:

"Near Midair Collision (NMAC) - An incident associated with the operation of an aircraft in which the possiblility of collision occurs as a result of proximity of less than 500 feet to another aircraft, or a report is received from a pilot or flightcrew member stating that a collision hazard existed between two or more aircraft."

If we implement NAS procedures must we therefore institute the implicated and relevant US Air law to support the operation of that airspace and the operations within that airspace or does this leave the situation somewhat defunct?

Or do we disconnect from the "Conga Line of Ar$e Sniffers" , dare to be different (for once Australia) and fix this mess up?

21st Dec 2003, 13:37
Perhaps the aforementioned Minister would like to be on-board an aircraft when they occupy the same piece of sky together!

21st Dec 2003, 16:32
I just wanted to concur with Captain Claret who was pleading the case for him flying into Alice Springs, where there is no radar and substantial air traffic, of all types. At least in the case of the Virgin near miss, the controller had radar at his disposal. He could see the aircraft and with the help of DTI the Virgin was able to acquire the aircraft visually. In Alice Springs the controller will not have the lightie on his non-existent radar, and since the guy had not flightplanned there would be no record of him being in the area.

So if this had been into Alice, the Lightie calls up ATC requesting to go IFR. The ATC, with no radar, would have to firstly get flight details, position information etc, and then work out how he could get a clearance. All this time he would be unaware the Transponder was not transmitting altitude. The 737 would continue to descend, and without the aid of the DTI from the controller, or from TCAS info with altitude information, would he visually acquire the lightie?? Since there is no radar in the entire area, I am sceptical that all the lighties around Alice use there transponders, and if they do, whether they work or are accurate, so if you remove the transponder and hence the TCAS from the scenario it gets truly scary.

But of course Captain Claret and all the other RPT pilots into Alice have nothing to worry about, cos John Anderson said its safer.

P.S How is it that VB are allowed to have a company policy for pilots to disregard RA's if they have visual with the aircraft concerned. If it is a requirement to have TCAS fitted and working, wouldn't it also be a requirement to respond to it?? I have seen times where having visual with one aircraft turns out to be visual with another, and thats where ignoring the RA scares me. Just my opinion.

21st Dec 2003, 16:42
I am a big fan of pilot discretion. I don't think they should blindly follow TCAS. That implies that TCAS is infallible. TCAS will often ask aircraft to cross levels, which can only rarely be the best option (imho).
Have had a situation where the aircraft (AN 737 vs Southern Dash8)were fully clued up (traffic passed etc) but due to high rates climb/descent received RAs. They both (sensibly) elected to follow the clearance, confirmed verbally, and continued on. The TCAS was asking them to cross levels, which would've reduced the sep to min miss distance (600' 1nm?). Stopping at their assigned levels was the better option in this case, and I don't believe that option should be taken away.

Shades of grey, mate, shades of grey.

TCAS is a can of worms though, and needs sorting out. It certainly shouldn't be the prime seperation device between lighties and jets, a la NAS class E.

Capt Claret
21st Dec 2003, 19:24
In the example you give of the AN73 and a Dh8, I think pilot discretion worked because both crew were aware of the other. Other than the scenario where crew are aware, I think discretionary adherance to TCAS can be frought with danger.

I've seen numerous TCAS paints split into multiple paints. Whether this is multiple aircraft or a glitch in the display I can't say. I would however be concerned to ignore a RA simply because I thought I had the traffic sighted, as if there was multiple traffic the wrong decision could be fatal.

I'm dissapointed that from a SA point of view, we're not advised of proximate traffic, due in part to the ever increasing reliance of electronics combined with reduced ATCOs to be able to pass on the info.

Getting a TA at F300 out of the blue certainly wakes one up! :\

21st Dec 2003, 19:52
Cap Claret, you shuld be getting that service, on a workload permitting basis. Called merging target procedure.

Capt Claret
21st Dec 2003, 20:01
The bulk of my flying is non radar thus no visible targets to merge, though sometimes info is passed.

There have been a few occasions though when an unannounced opposite direction aircraft has impinged on the super accurate altitude hold of the 146 and the ensuing TA has resulted in a rapid change in posture. :}

21st Dec 2003, 22:37
Holy hell - I can't believe we're talking about "eye-balling" and second guessing the TCAS computers.

I wonder what the two JAL pilots will do in future when they get an RA in conflict with an ATC instruction? (the guy who tried to second guess the TCAS computer [and got it wrong] will probably never get another chance)

Most jet transport pilots have probably experienced a TA or even RA when on climb/descent at high rate to an altitude restriction because of opposite direction traffic. Remember how much time you had to react? And as often as not, its at the change over from departures to control frequency, so there's absolutely no chance to "self-co-ordinate".

Ever been gazing out the window and spotted another dot in the vastness of the atmosphere and tried to determine whether it was above you or below? Most of the time my guess has turned out to be hoplessly wrong! The JAL guy did the same thing - and got it wrong!

I'll be following my RA - I just hope YOU do too!

22nd Dec 2003, 02:10
I think we have hijacked this thread away from an important topic, but I think talking about TCAS is relevent (it seems to have become the main seperator in NAS classE).
I can't believe we're talking about "eye-balling" Isn't "attempt to aquire the intruder visually" high on your RA checklist? It ought to be, as the other guy may very well not be following his RA. What guarantee do you have that he is? I am not advocating disregarding RAs, just trying to point out they, and the procedures surrounding them, are not infallible. The next generation of TCAS will be a marked improvement.

I was always encouraged to pass traffic if I had time (you needed definite passing anyway, and getting you to sight and pass was always the best option. We had a fair idea when passing would occur:8 so why not use it).I think discretionary adherance to TCAS can be frought with danger So can blindly following the RA. In the absence of other info, I agree follow the RA. I just don't think taking discretion out of it helps. You cannot make rules for every situation. I really feel for you 146 guys (aside from the 146:hmm: ). NAS must have turned routine descents into russian roulette? Glad I'm out of it.

Seems a body of thought that I'm advocating "down with TCAS". Certainly not. I am saying "down with NAS, and it's reliance on TCAS".

22nd Dec 2003, 02:18
One of the problems that TCAS has caused is putting the controllers in a situation where they don't know whether they should give instructions to an aircraft that they believe is responding to an RA. Reading the findings of the SkyGuide disaster, one of the recommendations was for controllers if they believe the pilots are responding to RA's is to pretty much shut up and wait for it all to be over, as by giving instructions you may make the situation worse.

The problem is firstly you are never sure if an RA is being followed as the pilot will usually tell us after he has carried out the avoiding action, secondly our radar info is behind real time, so we may be descending a guy back into a guy he has already climbed above, and finally it is not in our nature to sit on our hands and watch it all turn to "Kak"(sorry been hangin round Sth Africans too much := )

I do still feel that if we are going to make TCAS carriage mandatory (as it is here for all but the really light low stuff, which basically there is none of), then we need to all know the rules we are playing by. Either the pilots have discretion to decide whether they respond or we need to know that the pilots will always follow the TCAS and ignore ATC instructions. I go with the ignore us and always follow the TCAS completely. I understand Ferris's logic of there are cases where both visual etc. but there are also cases where one aircraft takes your advice, and the other one doesn't and when there is 20 seconds or less to decide, I would prefer to have some black and white rather than grey.

BTW Spod, on a previous thread you mentioned the old Rogue pilot. I do remember how he used to always need to divert right of track round weather which took him to WENDY (still makes me quiver when I type that name!!) rather than ARBEY. Amazingly the weather was only present when we were using RWY 34 in Melbourne. Also saw in another post, you're still sitting in the Crisper :ugh: The guys on TMA must be gonna drop off the perch soon! A few of them looked like they were close when I left :p

22nd Dec 2003, 04:28
Just a couple of random comments:

As I understand the TCAS does not provide lateral direction, only vertical as a solution to an RA and will desentisise below 1000 feet AGL which must be a bother landing at busy G/CTAF? So even with this form of defence we have imperfectness.

I have some time up at Alice (in my deep, dark and best forgotten past) and this is where I am most concerned for the fast aircraft, because whilst the ATC service comes with high regard the C into E situation with no RADAR and quite dense levels of both Bush and itinerant traffic is clearly an increased hazard with NAS. The upside is that most of this traffic is on predicted routes (which ironically correspond with IFR) which means there is a known quantity. Perhaps a method of traffic management (by crews or ATC) may assist to get fast aircraft off those routes for descent or climb to minimise the hazard - ie IFR route segregation with the majority of VFR.

SPODMAN mentioned "Merging Targer Procedures (MTP - my abbrev.)" which is something ATC have been doing for ever, on a workload permitting basis. My experience at Alice was a F28 departing the Rock for Alice to maintain F280. Just before he called ATC (and got the crossing traffic) he had a heart stopping experience when, in the middle of AUS, on a clear blue day, his cockpit was thrust into darkness, followed by the sight of the large underbelly of a B747 overflying him at F290 on crossing route, T27.

Traffic even in non-RADAR C airspace is a good call - but doesn't need to be War and Peace.

Just thinking that we are getting more and more dependant upon the words "workload permitting". A Claytons service maybe?

22nd Dec 2003, 06:34
Couple of things

Firstly George

Have had a situation where the aircraft (AN 737 vs Southern Dash8)were fully clued up (traffic passed etc) but due to high rates climb/descent received RAs

I agree with you that in your situation at that time the levelling of the aircraft at their assigned levels as opposed to responding to the RAs was satisfactory. Unfortunately today these aircraft may think that the traffic giving them the RA is the one they can hear on Centre with a level clearance but there could be some other there happily ploughing along not talking. AN737 assigned FL170 on descent, Southern Dash assigned FL160 on climb and right in between is MGC passing FL165 on climb or descent 1200 on the transponder. Both get RAs.

We now have the unknown in this airspace and I would hope that pilots remember this when they think they have expected traffic sighted.


The Merging Target Procedure has ceased to exist. AIC H8/03 (from memory) has expired and through a fabulous bit of stubbornness on both sides, the AIC was not promulgated into MATS or AIP and is no longer in existence. I note that this was never made clear to everyone who had received training in its existence. I only found out due to asking a question that was completely unreleated.

22nd Dec 2003, 12:26
To be honest, Plazbot, I hadn't thought of that. Yes, back when mine occurred it was the relatively safe classC. Now, with this NAS rubbish, anyone could be there (not necessarily squawking, either. Wouldn't that be nice- get an RA and have to look out for other VFR traffic {such as C421s at FL175 at CANTY} not necessarily squawking?!?!).
NAS should be stopped until ADSB is available. It's a disaster waiting to happen.

Merging Target Procedure? Isn't that something Fighter Controllers learn? Usual AsA management competence at work, I see.

22nd Dec 2003, 14:20
Well ... as you guys talk, at least the Ghost Who Walks and I will be safe if we meet each other as we'll follow our RA's.

As I read this thread I'm appalled to note there are those who would doubt an RA. Doubt the RA and you may join those who have fallen from the sky (God rest their souls).

As for me ... I'll look while it's squawking "Trafiic Traffic", but should it say "Climb, Crossing Climb" that's what I'm gonna do. And you better be doing what it's telling you.

22nd Dec 2003, 15:13
As a controller in the London TMA I can say that I have seen alot of instances of unnecessary TCAS warnings. BUT and its a big BUT! the times that TCAS has saved an a/c or two make up for it. In my profession, we are taught that as soon as a pilot says that he is reacting to a TCAS then he is totally responsible for his own separation. TCAS is a last minute separation tool, it will not provide standard separation, it will get you a miss and that is all. If you can guarantee that the a/c you see is the one you are supposed to be missing then fine, but tcas will give you a miss definitely even if your human eye doesn't agree.

Finally as a controller, me and my collegues have had to change our working practises because of TCAS (closure rates etc). In the beginning we thought it was a pain in the preverbial. Now we believe it is essential and would not like to be without it. TCAS has made the environment safer and saved several pilots and controllers from some very nasty situations.

23rd Dec 2003, 05:55
Agree with the most recent posts. A TCAS RA is to followed unless it is clearly unsafe to do so. This was strongly reiterated after the midair over Switzerland (where the Russian aircraft followed the air traffic controller's instruction which unfortunately was contrary to the RA instuction....). And let's not quibble about what "unsafe" means. If the RA is flying you into the ground or clearly into another aircraft that you have visual, then fair enough, don't follow it. But otherwise, do what it says. That is enshrined in QF's SOP's. The integrity of the protection it provides is based on everyone doing the right thing.

It does beg the question how another airline in Aus can be permitted to have a TCAS RA policy where they can elect not to follow an RA if the traffic is sighted (as per the ATSB report)..... Not having a go at DJ blokes as such, but you'd think CASA would be consistent in their application of this matter when approving company Ops manuals... Comments anyone?