'Hundreds' of close calls (merged)

[Here to Help]

'Hundreds' of close calls
By Lachlan Heywood
October 13, 2006 12:00am
Article from: The Courier Mail

AIR safety in Australia is under a cloud after more than 300 near misses in the past three years.
Article here:
http://www.news.com.au/couriermail/story/0,23739,20572431-953,00.html

[185skywagon]

From the article
A Virgin Blue and Sunstate Airlines plane also breached "recognised separation standards" en route from Mackay to Townsville.

Nearly 150 fires have been reported since 2003.

The figures were tabled in Federal Parliament by the Department of Transport and Regional Services.


Love ya work.

[UnderneathTheRadar]

Personally, I want to know where to hire a Cessna like this one
that the guy with the first feedback got to fly once........ :)
This may well mean that the small aircraft are not able to operate efficiently and are subject to significant ATC delays. But with a 747 burning 12500 litres per hour, and a cessna burning about 300 LPH, I believe its more important to have the commercial aviation running as efficiently as possible.
Perhaps he may find GA even more efficient if he puts the drain plugs back into his fuel tanks?
UTR.

[Rocky Rhodes]

Personally, I want to know where to hire a Cessna like this one
that the guy with the first feedback got to fly once........ :)
Perhaps he may find GA even more efficient if he puts the drain plugs back into his fuel tanks?
UTR.
Must be David Lowy's Dragonfly!:D

[peuce]

At last ... some excitement on the boards!

[Shitsu_Tonka]

I wonder how many 'close-calls' they have had in the US system?

After all, this has to be the first salvo in yet another NAS onslaught right?

With AUSFIC being dismantled, one wonders if 'aviation campaigners' (as the Courier Mail awards Mr Smith) would be better off addressing what if any service is going to be left for GA?

It is all very well to say that the radar should be used more , but who is left to do it? Those radar controllers will soon have a FIS function to cover as AUSFIC finishes. The US system still has FSS remember.

So once again, this is no US System.

Add to that the plans for further culling of ATC, and the lack of suitable applicants whilst the experienced people look to 'cut and run' overseas..... an interesting recipe.

If you want to bet who is going to lose out on service, just look at where Airservices gets 95% of it's income - it's not difficult.

[404 Titan]

****su_Tonka

Check your PM.

404

[Ex FSO GRIFFO]

YEAH!!!!

BRING BACK D.T.I..OCTA..............

That's Directed Traffic Information, to the uninitiated.......

And since 12.12.1991.....that's MOST of yas.........! ( For you VFR Types...)

Progress.....HHHUMPH!!!!!:= :=

Cheersssss:E :E

[Shitsu_Tonka]

Seems to be back.

[Ultergra]

Perhaps it has something to do with the fact that it does not make any sense.. I mean, call me stupid, but why is it a near miss, when they missed... shouldn't it be a 'near hit'? :8

[peuce]

.... I shouldn't have mentioned the captain of "E.A.T." (enthusiatic amateurs team)

[Here to Help]

i think because it mentioned the unmentionable, it was censored.

It didn't mention the unmentionable, it was simply a link to a newspaper article that did.

[SM4 Pirate]

OK so the headline was 300 near misses in the last 3 years... What are we counting here, breakdowns in separation standards, TCAS RAs, Failures to pass traffic in DTI, where does the 300 come from?

If it's TCAS RAs that is far from a 'Near Miss'; I have seen many RAs where the standard existed, always existed and remained in place despite the RA.

As an ATC who sees controllers getting stood-down when they have a BOS, (which is often far from a 'near miss'); I can't for the life of me remember more than a dozen or so in the past 3 years; so where are the 'facts' from?

And how does bringing in more Class E resolve the headline?

[Shitsu_Tonka]

Basically, I think the thread was removed (rightly or wrongly) because it was giving publicity to a certain agenda, by a certain agendee, where it is obvious from the lack of journalistic research, that it was baseless claim on loose information (one could almost suspect, it was 'fed' to them by a willing participant?)

This was already suggested in the previous replies.

I am quite happy for such threads to run because it gives us all a chance to point out the hyperbole and sensationalism of such threads.

What we need to ensure is that the threads don't get 'Coonaned'.


(A new phrase coined this week after the concentration of media power was approved - meaning, if the message doesnt' fit with the media owners agenda - don't publish)

I think in our newly litigious environment of PPrune DG, we need to continue to fight the fight, but without naming the names directly.

Let's face it - you all know who I am talking about right? But you can't prove it right? And neither can they. So let's continue to fight the crap with sound arguments - and also rescue the free publicity to the same old protagonsits by just calling them - "the same old protagonists"

On a completely different topic, did anyone else read the RAAA article on NAS implementation in the recent Australian Aviation magazine? An excellent article on a poorly rushed concept in my view. Does anyone have the text of it?

[Shitsu_Tonka]

The inspiration for this 'newspaper' article?

This question by Senator O'Brien perhaps? (http://parlinfoweb.aph.gov.au/piweb/TranslateWIPILink.aspx?Folder=HANSARDS&Criteria=DOC_DATE:2006-10-11%3BSEQ_NUM:133%3B)

[VVS Laxman]

Great link ****su...

Now correct me if I'm wrong, but the VCA column seems to be a bit light on for numbers.

If a VCA (violation of CTA) led to a BOS (Breakdown of Separation) would it get reported as a VCA or a BOS?

Hmmm, so what we have here is 309 'near misses' based on 309 BOS's. Of which there could be over 300 directly relating to "Farmer Joe's, Terry Towellers and Weekend Warriors" committing a VCA.:\

Never let the facts get in the way of a good story.:D Luv it.

[Shitsu_Tonka]

Yes tha VCA number surprised me to, considering the little bit of airspace I am familiar with probably has around 50-80 VCA's every WEEK.

Some readers have PM me that they could not open the link?

If one cast's their mind back to the many incarnations of NAS, we had TCAS RA's being described not as BOS but as Airprox - surely an airprox should be included under the Courier-Mail classification of a "Close-Call"? If so, I would bet that the number of "Close-Calls" was a lot higher during those heady times. This was in (the best) radar coverage (in the world).

http://www.atsb.gov.au/newsroom/2004/release/2004_33A.aspx

Interestingly, at the time, there was an attack on the ATSB and Airservices:


ATSB COVERS UP AGAIN FOR AIRSERVICES’ INCOMPETENCE
RADAR NOT USED AGAIN IN NEAR MIDAIR
PLANS TO ROLL BACK TO 1930s MARCONI SYSTEM

In my opinion (disclaimer: opinion only) the confusion that has lingered since the many NAS stops and starts has only resulted in more VCA / BOS / Airprox / Close Calls / Brown Trousers than prior to it's introduction.

But hey thats just my 'belief'.

With the dismantling of AUSFIC, and those duties being placed on the sector controllers, the airspace restructure, and the ATC staffing review, the issue of whether ATC can discharge their current duties should be of more immediate concern - instead of calling for the addition of extra Radar services.

(Add to this that by this time next year Airservices will probably have a new CEO - and no doubt a whole bunch of new neat ideas, and associated budget milestones (!) to make his mark.)

Remember: Fight the issues - not the Personalities

[GaryGnu]

I wonder how many 'close-calls' they have had in the US system?
After all, this has to be the first salvo in yet another NAS onslaught right?
A quick search of the US FAA Near Mid Air Collisions (NMAC) Database, with all its acknowledged shortcomings of subjectivity and under reporting, shows 422 NMACs for the period 01Jul03-30Jun06.
I must admit to thinking this was a rebirthing of a NAS Agenda. The crucial difference this time is the identity of the politicians who the chief agitator(s) for NAS (may) have managed to engage. Previously it was the Minister for Transport now it is the Opposition spokesman of Transport. Like him or hate him Senator O'Brien won't accomplish much in terms of NAS implementation from the opposition benches.
Interestingly, the recently released Airservices discussion paper on Australian Airspace Architecture assumes that NAS Implementation remains Government policy.
My opinion is that given how much political pain NAS caused his predecessors (once and twice removed), the current Minister will be a little more circumspect in forcing through implementation of the remaining NAS charactersitics.
Don't forget that all remaining NAS Charactersitics will have to be put through the proposed risk and Cost-Benefit analysis framework. That may just give the minister enough cover to justify no further implementation.
****su,
Airprox was included in the numbers quoted in the Courier Mail.

[Chimbu chuckles]

One could be forgiven for a certain sense of deja vu...again.

Can someone refresh my memory...battle fatigue don't you know...wasn't 2004 a NAS2b year...and 2005?

[SM4 Pirate]

...Interestingly, the recently released Airservices discussion paper on Australian Airspace Architecture assumes that NAS Implementation remains Government policy....

Gary, where would someone find such a discussion paper?

[peuce]

With the dismantling of AUSFIC, and those duties being placed on the sector controllers, the airspace restructure, and the ATC staffing review, the issue of whether ATC can discharge their current duties should be of more immediate concern - instead of calling for the addition of extra Radar services.


This also throws a spanner in the works for any NAS acceleration. It's a whole different ATS environment, so I would presume that new safety assessments, HAZIds, Cost/benefit analyses etc will need to be done.

[Shitsu_Tonka]

Facts or rhetoric?:

"The skies are getting busier and we have an airspace system designed in the 20s."

The Airspace system we have now has in fact been redesigned again and again - with a marked acceleration in it's design changes and characteristics since about....1991 as it happens.

It could be legitimately argued therefore that any perceived increase in 'close-calls' may in fact be partly as a consequence of these changes themselves, or indeed as a result of the sheer number of changes.

Just in the last few years there has been a myriad of changes - and aborted changes - as a result of the NAS system as well as other new technologies and techniques. NAS itself remains very controversial, and widely lauded as an excellent example of how not to implement critical changes to a complex system. That is not just a personal opinion - it is the documented view of various Airline Pilot groups, the Air Traffic Controllers Association, and the Regional Airline Association.

The system we have now is nothing like the 1920's - in fact there was no system in the 1920's as there were only a handful of aircraft in Australia.

Nor is the system we have now recognisable to anything like that of 20, 10 or even 5 years ago.

There have been 309 near misses in the past three years, including 57 in the first half of this year.

Well no - in fact there were 309 instances of the following:

From the Ministers Response:

A breakdown of separation standards, being a failure to maintain a recognised separation standard (vertical, lateral or longitudinal) between aircraft that are being provided with an air traffic service separation service or an airprox

Note the phrase - or and Airprox*.

I guess it is not as sensational or sexy to admit that a Technical Breakdown of Separation can mean aircraft passing with barely 100 km between them!

"increased air traffic required greater use of radar."

The radar where it exists is used... where it exists! There can not be a greater or lesser use of it. What relation this has to the number of breakdowns of separation is not clear - because the statisitcs do not show where the BOS was in a radar or procedural environment (where radar coverage / surveillance coverage does not/did not exist). The great majority of those BOS are just as likely to be in a non-Radar environment - so any 'increased use of the radar' (whatever that actually means) will have little effect on the statisitcs - unless of course we install radars everywhere (like in the US perhaps?).

--------------------------------------------------------------------
*Airprox (Australian Definition) - An Airprox is an occurrence in which 2 or more aircraft come into such close proximity that a threat to the safety of the aircraft exists or may exist, in airspace where the aircraft are not subject to an air traffic control separation standard or where separation is a pilot responsibility.

Airprox in fact often make the news through a press release:

http://www.atsb.gov.au/newsroom/2004/release/2004_36.aspx

http://www.atsb.gov.au/newsroom/2005/release/2005_04.aspx

Reports of Airprox** overseas:

Airprox in the UK has a different definition (see links below)

19 APR 2005 UK Airprox Board publishes 2004-Q1/2 report
The twelfth report of the UK Airprox Board (UKAB) was published today. It covers the 109 Airprox reported by pilots and air traffic controllers between January and June 2004. Although the 109 Airprox compares with an average of 93 for the first six months of the years 2000-2003 inclusive, more than half the 109 incidents were assessed as `no collision risk`. During the first six months of 2004, there were eight risk category A Airprox (actual risk of collision), none of which involved civil airliners. (CAA)
Link: http://www.ukab.org.uk/

[Scurvy.D.Dog]

Spot on ****s :ok:

[Andu]

IMHO, if today's airways were designed in 1991, like far too many Government projects, the specs used were from 1958.

The following is copied from a similar thread on the main board.
FACT: the laws that govern our airways use were drafted in a time when tracking was done with VAR/radio range, ADF or VORs.

FACT: the vast majority of jet aircraft using today's airways are equipped ith some form of precision tracking aid like INS, IRS or GPS.

FACT: the human element is still in there somewhere, and humans, even the most professional, make mistakes.

FACT: in the days of VAR and ADFs, two aircraft flying on reciprocal tracks at the same level on the same airway had a better chance of BOTH being struck by lightning at the same instant in time than of hitting (or even seeing!) each other.

FACT: with GPS navigation, the same no longer applies. Two aircraft flying at the same level on opposite tracks will fly within a wingspan of each other and their altimeters now HAVE to be so accurate (to be allowed to fly within RVSM airspace) that they WILL be within 50' of each other (ie, they won't miss vertically either). They WILL hit each other unless timely (ie, very rapid and juts as importantly, CORRECT) avoiding action is taken by BOTH pilots. The tragic midair between the DHL freighter and the CIS passenger aircraft over southern Germany some years ago proved that that cannot be relied upon.

These lead me to a final FACT: it's well past the time that someone in authority bit the bullet and accepted that technology has overtaken the rules we work under. We simply HAVE to accept that even with all the high tech safeguards that have been introduced, all the holes in the cheese can still tragically align, as they seem to have done so in this case.

It's time we re-design our airways to accommodate a small right offset, at least in the cruise phase.

... and 'someone in authority' will only act after there's an outcry from the professional pilot group that is so loud and long lasting it cannot be ignored.

[peuce]

If we're worried about jits ending up in the same place at the same time ... wouldn't it be better to concentrate our efforts on NOT letting that happen ... rather than letting them wander off course, in case they do?

It's a bit like stopping your car at every green light ... incase someone drives through the red and hits you. That concern might be better allayed by supporting more driver training, or installing bigger or better red lights ... to reduce the driver's inclination to go through the red light, or the light not being seen, or the electronics failing on the lights.

The bottom line being that you will NEVER prevent all stuff ups ... you can only work to reduce them.

[Shitsu_Tonka]

Andu,

Whats your point?

[PPRuNe Towers]

I think you actually answered yourself in your last sentence peuce if you are refering to andu's post directly above yours.

100 metres offset - that's all we need for the stuff ups. That's all we ever needed since we went glass/IRS/GPS. But people on the ground know better. I think it must be because it would look untidy.

Regards
Rob

[Andu]

Peuce, as has been said by others quite some years ago on this site, the current situation is akin to walking directly in line with a machine gun that the shooter assures you is 'safely' aimed over your head. Or driving down the highway at high speed with your lights off straddling the centreline *knowing* that no one's coming the other way because some traffic cop has assured you over the phone that he's stopping all opposite direction traffic.

Sometimes, the cop gets it wrong or the machine gunner slips with his aim. Wouldn't it be easier - or smarter? - to drive on one side of the road or stand out of the machine gunner's azimuth?

JUST
IN
CASE?

----

****su, like many other ATCOs, you seem to take the offset idea as a personal affront to your professionalism. It's anything but - just a all too easy to implement last ditch LIFE SAVER if all the other 'holes in the cheese' line up one day - as they unfortunately do.

It would be so damned easy to implement. The offset kicks in whenever LNAV is selected. If track select or or heading select is active, the aircraft points directly at the next waypoint. If that's too simple, surely it wouldn't be too difficult to have the offset disabled when the aircraft is within certain lat and long co-ordinates, (the busy areas ATCOs say offsetting would be a problem).

154 Brazilians would still be alive today if the suggestion, I think pushed very heavily by 410 on this site ten or more years ago, had been implemented. And they're not the first. The Luftwaffe and USAF crews who died off the West African coast in very similar circumstances would also still be with us.

If the 154 dead had been US citizens, I'd be guessing that there'd be a class action suit hitting the courts within weeks against ICAO for not implementing offsetting years ago.

[DirtyPierre]

Andu,

Offset is good for reciprocal tracks, but it wouldn't stop a Lake Constance happening again.

Oz is full of one way routes that cross other one way routes.

[Shitsu_Tonka]

Andu,

Calm down mate.

I have no problem with offset in the enroute environment. Don't try it in the TMA however as the controller will get very snakey, as well as earn many frequent short holidays preceded by tea and bikkies.

As DirtyPierre beat me to it however - Offset is only useful for exact opposite direction routes (i.e. two-way routes, where Radar generally doesn't exist).

Anywhere else it does nothing - just changes the point of the potential MAC.

In 'practical terms', offset (within reason)- in a procedural environment has no effect on ATC.

Andu - what angle did the GOL 737 and Legacy collide? If it wasn't at 180 degrees, what would offset as a mitigation concept achieve?

[Dick N. Cider]

FACT: in the days of VAR and ADFs, two aircraft flying on reciprocal tracks at the same level on the same airway had a better chance of BOTH being struck by lightning at the same instant in time than of hitting (or even seeing!) each other.

FACT: If you buy a lotto ticket on Wed for the Sat draw, you have a better chance of accidental death before the draw than winning it - so what?

Airservices Australia General Manager ATC announced a national route restructure based upon enroute nav RNP1 or RNP2 for completion by 2010 early this month. Offsets in enroute phase, if you're talking 100m, are to all intents and purposes invisible to us. If you're ADS-C we might know about it by alerts (dependent upon parameters in our system) because your intent group doesn't match your flight plan that you submitted. Route structure really determines if offset is going to help.

The only real fact that matters is if you're planning to be at the same point, at the same time, at the same level as another aircraft, these days "big sky" theory ain't gunna help.

[MTOW]

What I'd like to see is something that avoids a TCAS RA in as many cases of potential conflict as possible, because a TCAS RA relies on both pilots reacting instantly - and correctly - to avoid what happened in Brazil. Unfortunately, the Lake Constance collision proved that despite the best will in the world and God knows how much training by airlines, you can't rely on the other pilot to do the right thing. 100m offset won't stop an RA being generated (nor would .5NM, but I'd feel happier with that if it didn't upset ATC too much).

You're never going to come up with a system that covers all eventualities. With a crossing conflict, both aircraft have to reach that one point in the sky at the very wrong moment. With reciprocal tracks, the two aircraft could be occupying the exact same line along the ground for hours.

Surely Andu's idea of the offset being enabled only when in LNAV has some merit. Failing that, just give pilots permission to use offset in the cruise in all but certain designated areas, (as they already do over the North Atlantic). Offhand, I can't think of any area in the cruise that would need to be excluded, (but I'm sure someone will come up with one or two).

[peuce]

Okay Rob, I take your point.

So, some pilots already do it now in enroute ... ATC surveillance tolerances aren't good enough to see it ... what's the problem? Continue doing it. No rule required.

[Capn Bloggs]

I agree with Andu here. Where I fly in Oz, there are hardly any oneway routes outside radar/ID coverage and I marvel at how little lateral sep exists when I pass jets going the opposite direction every day. And I certainly concur with the comment that when tracking with VORs/Omega, there was always an "inbuilt" track error that helped the big-sky theory work.

We are already officially allowed to offset to the right in Australian OCA, so why not by a little bit in continental airspace?

There are problems that will need to be overcome though:

+ some FMSs cannot be set to terminate an offset at a downtrack waypoint, so the crew has to remember to do that later on,
+ some FMSs cannot have an offset of less than 1nm,
+ many NPAs are flown in LNAV, and there would have to be some FMS reprogramming to prevent a crew inadvertently leaving an offset in during a approach.

[Here to Help]

Okay Rob, I take your point.
So, some pilots already do it now in enroute ... ATC surveillance tolerances aren't good enough to see it ... what's the problem? Continue doing it. No rule required.

There are some routes that require exact tolerances, some are due to the proximity to military airspace. In one case I had observed a domestic jet tracking 0.2nm right of track. The pilot confirmed this and I had to instruct them to regain track to remain clear of military controlled airspace, with resulting coordination to the military unit for boundary traffic. And this was on a one way route.

Some ATC routes/boundaries require exact tracking for coordination purposes and even the smallest offset can make a difference. Pilots will be largely unaware of which routes this applies to. Tracking offset, without approval from ATC can result in additional workload and in some case, technical breakdowns of separation.

[Blockla]

A couple of good articles in the latest "Controller" magazine about automation in ATC and ACAS and down linking of RAs. One article referred to 70+ RAs a day in Europe, many without needing variation to the clearance as the VNAV approaching the cleared level was too great for TCAS parameters i.e. the boxes don't yet share Cleared level info.

More interesting was a French study about TCAS RAs, where up to 28% failed to respond adequately to an RA either in time or within the range of the vertical 'Resolution' and further over 10% fail to comply at all even post 2002.

Wish I could quote more accurately but I did read it at 3am last night.

I also saw a ppt presentation of the Brazil incident, it would appear that the Embraers winglet took off the 737 outer wing near the aileron thus making the left aileron inoperable or missing shortly after the impact.

[Capn Bloggs]

ST,

what angle did the GOL 737 and Legacy collide?

180°, according to Flt Intl of 10-16 Oct.

[Shitsu_Tonka]

Thanks Bloggs,

definitely a case for offset - 2-way routes.

[Wiley]

It’s understandable that we have a hard time convincing those who sit on the ground and write regulations about the benefits of offsetting, but what amazes me is the incredible lack of imagination in so many of my colleagues who fly the line and daily watch a succession of aircraft (with a closing speed of near 1000 kts) fly directly - and I mean directly over or under their aircraft. And still the majority of them resist offsetting and don’t use it even when it’s allowed.

It's been said before on this thread, but I'll say it again - if offsetting was made SOP – or even better, made mandatory – in all but terminal areas, or at the very least, whenever outside radar coverage, 154 people would still be alive today.

I'm told that journalists read these threads. If that's the case, maybe one of you could dredge up some 'shock! Horror!' headlines over this point - that today's supposedly modern air traffic system forbids pilots from using this simple ‘last ditch’ procedure that would undoubtedly save lives should all other safety procedures fail - as they did in this case, and have done in the past.

*****

Here to Help, how in the world could an aircraft that it .2 of a mile off track on an airway be infringing military airspace? Even if he was 2 miles off track, he’d still be well within the confines of a standard enroute airway. (No one is asking for offsets within terminal areas.)

[Shitsu_Tonka]

Wiley,

how in the world could an aircraft that it .2 of a mile off track on an airway be infringing military airspace?

Only through very poor design of Military Airspace boundaries vs. Routes.

We have a fairly crappy one out of BN - admittedly it's Radar so not really a problem, but have a look at the IBUNA track (BN R-286) vs. the AM Military area.

As far as the non-radar areas are concerned, I agree the .2nm should never cause a real problem. (In the world of common sense).

[Here to Help]

Here to Help, how in the world could an aircraft that it .2 of a mile off track on an airway be infringing military airspace? Even if he was 2 miles off track, he’d still be well within the confines of a standard enroute airway. (No one is asking for offsets within terminal areas.)

The route (in enroute airspace) concerned runs 2.5nm (half the radar standard) parallel to a military airspace boundary. Any aircraft operating closer than 2.5nm from the boundary necessitates prior coordination with, and approval from, the military ATC. So, to avoid a "breakdown of coordination", the civil ATC must coordinate an aircraft diverting, even if 0.1nm offset.

It's obviously a procedural issue - transparent to any pilot - but because it is a requirement for coordination, such an offset becomes extra workload for the controller to monitor and approve. Not the most ideal of airspace designs, but like I said, some routes require exact tracking for ATC coordination requirements.

[gaunty]

****su_Tonka

Been waiting for this to appear on the website to save me typing it out the hard way.

It is IMHO the final word on the fallacy of "see and be seen" in the modern environment at least the one that I work in.

See-And-Avoid A Dangerous Way To Separate High- and Low-Performance Aircraft

Jan 17, 2007
By Patrick Veillette, Ph.D./Business & Commercial Aviation


The smoke plume on the east side of Los Angeles on the afternoon of Aug. 31, 1986, was clearly visible from the balcony of our apartment adjacent to LAX. The local news was reporting that an airliner had crashed into the suburb of Cerritos. My roommates, all Los Angeles-based pilots from a half dozen airlines, stood on the balcony watching that sick black plume rise. No one said the obvious, that the dark column marked the place of death for many.

We subsequently learned that a pilot of a Piper PA-28 had errantly wandered into what is now Class B airspace without a clearance and without an operative altitude encoding transponder. The flight crew of the Aeromexico DC-9 had only the slimmest of chances to spot and avoid the Cherokee, and unfortunately luck wasn't with them on that day. When the NTSB finalized its report, it found limitations with the "see-and-avoid concept to ensure traffic separation" as a contributing factor to the disaster that took 82 lives.

That inflight collision was eerily reminiscent of another eight years earlier when a Pacific Southwest Airlines Boeing 727 lost sight of a Cessna 172 while on approach to San Diego's Lindbergh Field. The flight crew of the fast moving 727 lost sight of the Cessna and thought they had actually passed the slower aircraft. Unfortunately they had not and 138 people died in the collision that followed. A photograph of the last moments of the 727's dive serve as a gut-wrenching reminder of the inadequacy of eyeballs as a primary collision avoidance tool.

On Jan. 15, 1987, a Mooney M20 pilot was practicing holding patterns near the extended approach path into Salt Lake International Airport and inadvertently entered SLC's airport radar service area. Approach Control wasn't receiving an altitude read-out from the Mooney's transponder and unfortunately the practice holding pattern roughly coincided with the traffic pattern for Salt Lake City Municipal No. 2 Airport, a general aviation facility located roughly six miles to the south of SLC, thus adding further confusion as to the exact location of the Mooney. At the same time a SkyWest SA-227 Metroliner was being vectored to the final approach course for SLC, its pilots attempting to locate traffic pointed out by ATC. Despite the good weather, the Metro pilots never spotted the Mooney because the two aircraft collided over Kearns, Utah, raining aircraft parts on the residential neighborhood and killing the 10 people aboard the two aircraft but somehow avoiding any loss of life or injury to people on the ground.

Just five days later, a U.S. Army U-21 King Air collided with a Piper Chieftain near Independence, Mo. Six people died in that crash. The NTSB determined that the probable cause of the accident was the failure of radar controllers to detect the conflict and to issue traffic advisories or a safety alert to the flight crew of the U-21, and the inadequate vigilance of the pilots. However, the Safety Board also cited deficiencies of the see-and-avoid concept as a primary means of collision avoidance, and the lack of automated redundancy in the air traffic control system to provide conflict detection between participating and nonparticipating traffic.

Shortly thereafter, the NTSB recommended the FAA "expedite development, certification and production of various low-cost proximity warning and conflict detection systems for use aboard general aviation aircraft."

Unfortunately, that recommendation was still unrealized when five years later, on Sept. 11, 1992, an MU-2 pilot attempting to pick up an IFR clearance while departing VFR from Greenwood (Ind.) Municipal Airport, collided with a Piper Saratoga inbound for the same airport. The controller pointed out the Greenwood airport to the PA-32's pilot when the aircraft was approximately three miles out, at which time VFR radar service was terminated. The MU-2 had just departed the airport and asked ATC for his IFR clearance to CMH. The controller looked away from the radar screen to locate the proper flight progress strip and did not see the fast-moving turboprop depart from Greenwood. The controller then issued a squawk code and altitude to establish radar identification. It was during those seconds that the incoming PA-32 and outbound MU-2 collided. The Mitsubishi pilot and four passengers and the Saratoga pilot were killed. Two people on board the Piper were seriously injured.

The NTSB determined that the probable cause of the accident was "the inherent limitations of the see-and-avoid concept of the separation of aircraft operating under VFR that precluded the pilots from recognizing a collision hazard and taking actions to avoid the collision." The report concluded that the accident "again underscores the need for low-cost proximity warning and conflict detection systems for use aboard general aviation aircraft."

Now, 20 years have passed since the NTSB issued its original recommendation to expedite development, certification and production of low-cost proximity warning and conflict detection systems for general aviation. And while some systems are in place, "see-and-avoid" remains the primary means of separation between high-performance turbine and low-performance general aviation aircraft sharing the same airspace.

While a "Mode C veil" has been erected 30 nm around Class B airports that seems effective at preventing inflight collisions there, a system-wide solution for preventing collisions in other airspace, especially where high-performance turbine aircraft mix with lower performance general aviation aircraft, has yet to be implemented.

In the meantime, the wreckage continues to pile up. On April 4, 1998, a Cessna CE525 collided with a Cessna 172 over Marietta, Ga., killing five. On June 23, 2000, a Learjet 55 collided with an Extra 300S over the busy skies of Boca Raton, Fla.; four people died as a result. On Oct. 17 of that same year, a Gulfstream GIII collided with a King Air C90 while both aircraft were on approach to Van Nuys (Calif.) Airport; the pilots managed to land their aircraft without injury to anyone aboard. Most recently, a Hawker 800XP descending into Reno collided with a Schleicher ASW-27 sailplane near Minden, Nev., a popular soaring location. Somewhat miraculously the glider pilot managed to parachute to safety and the crew of the damaged Hawker was able to execute a single-engine, gear-up emergency landing at the nearby Carson City Airport. Everybody walked away.

FAR Part 91.113 places the responsibility to see and avoid other aircraft squarely on the pilot, stating, "When weather conditions permit, regardless of whether an operation is conducted under IFR or VFR, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft."

Using this regulatory precedent, the NTSB has found "failure to see and avoid, inadequate visual lookout, or failure to maintain visual and physical clearance" as the probable cause in 94 percent of the inflight collisions. The Safety Board can keep issuing such causal statements, but that won't change the underlying problem that the see-and-avoid concept isn't reliable as a primary or even secondary means of separating traffic.

Harold Marthinsen, former director of the Air Line Pilots Association (ALPA) safety engineering department, asks, "Do pilots really need a regulation telling them to avoid midair collisions? Pilots have a self-vested interest in preventing that from occurring. It is publications like the FAA's Advisory Circular on collision avoidance that help perpetuate the idea that all you have to do is pay attention, look out the windshield, and you won't have a midair collision. Rather, the FAA should be telling pilots how dangerous the see-and-avoid concept really is as a means of separating aircraft."

See-and-avoid involves a number of steps, all of which are inherently prone to error. First, the pilot must be looking outside the aircraft. Second, pilots must search the visual field and detect objects of interest, most likely with their peripheral vision. Next, the object must be looked at directly so it can be identified as an aircraft. If the aircraft is identified as a collision threat, the pilot must decide what evasive action to take and then follow through correctly and in a timely fashion.

So how well does the concept work? According to Craig Morris of the DOT's Bureau of Transportation Statistics, each year there are an average of 15.6 midair collisions in U.S. civil aviation, and that number may only hint at the scope of the problem. In an average year, NASA's Aviation Safety Reporting System (ASRS) receives approximately 577 pilot reports of near in-flight collisions between various types of aircraft. Specifically with regard to business jets, the FAA's near midair collision (NMAC) database included 226 NMAC reports filed by pilots of business jets for a recent 10-year period. In addition, the ASRS database for the same 10-year period had 806 reports of near midair collisions involving business jets. Just how close did some of the aircraft approach each other in these reports? Half of the reported incidents had a separation of less than 500 feet; some were even closer than that. And those are just the reported events. We really don't know how many close calls went unreported or how many pilots were simply unaware of a near disaster.

Those of us who fly the line don't need a bunch of statistics to tell us that flying into Martha's Vineyard or Nantucket (or Santa Monica, Van Nuys, etc.) on a VFR summer weekend is akin to running a gauntlet.

Writing in Aviation, Space and Environmental Medicine, a peer-reviewed journal of the Aerospace Medical Association, Morris held that "The 'see-and-avoid' concept has considerable physical and behavioral limitations such that pilots cannot reliably see and avoid conflicting traffic." A panel of reviewers would not permit an author to make such a statement unless it was backed by a preponderance of respected scientific research. Morris is among many respected aviation authorities who have expressed concerns regarding the limitations of the see-and-avoid concept.

The Australian Transport Safety Bureau issued a lengthy research report entitled "Limitations of the See-and-Avoid Principle" that stated, "Numerous limitations, including those of the human visual system, the demands of cockpit tasks, and various physical and environmental conditions, combine to make see-and-avoid an uncertain method of traffic separation." In addition, the Australian Bureau of Air Safety Investigation stated that "see-and-avoid is completely unsuitable as a primary traffic separation method for scheduled services."

Marthinsen stated in the International Society of Air Safety Investigators (ISASI) Forum (December 1989) that "See-and-avoid was originally a maritime concept developed for slow moving ships that is now out of place in an era of high-speed aviation." He went on to say that "No one is suggesting that see-and-avoid is not a useful tool for general aviation airplanes operating at uncontrolled airports -- it's the only thing available, and it works most of the time in this environment for which it was adapted. But it should not be relied upon to separate high-performance aircraft from lower performance general aviation aircraft -- a situation for which it was not designed."

There is a big difference between seeing an object under laboratory conditions vs. detecting another aircraft on a possible collision course out in "the real world." The NTSB considers 0.2 degrees as the threshold angle for detection (that is, the viewer could detect an object 20 feet wide at a distance of one mile -- Ed.), although Marthinsen says that figure should be increased by a factor of two or three for targets with low contrast or difficult patterns. The former ALPA director believes no one minimum visual angle can be specified because none can accommodate all variety of conditions such as haze, visible moisture or smoke. He noted that many visual acuity studies were done under favorable light conditions and with the subject staring directly at the object, in which case the image is focused directly on the fovea of the eye. The fovea contains the majority of the eye's cones and is responsible for the sharp vision we use in daylight conditions. If an object is six degrees from the fovea, that is, six degrees off a direct line by the viewer, it would have to be twice the size of an object directly in line in order to be detected. The threshold acuity drops off very rapidly for objects placed at angles away from the fovea. Further, all of these theoretical studies were conducted with fixed targets and viewers, never in motion.

FAA Advisory Circular 90-48C provides military-derived data on the time required for a pilot to recognize an approaching aircraft and then execute an evasive maneuver. The calculations do not include search times but assume that the target has been detected. The total time to recognize an approaching aircraft, recognize a collision course, decide on action, execute the control movement and allow the aircraft to respond is estimated to be around 12.5 seconds. Therefore, to have a good chance of avoiding a collision, a conflicting aircraft must be detected at least 12.5 seconds prior to the time of impact. It should also be noted that this study is over-optimistic for aircraft reaction time because the military study was in reference to agile fighter aircraft. The higher inertia and lesser maneuverability of civilian transports would add considerably to aircraft reaction time. The NTSB has used 15 seconds as the absolute minimum time for detection, evaluation and evasive action if the collision is to be avoided. Other studies suggest somewhat higher values.

Target detection is primarily a function of target size and target contrast, with size being, by far, the more important parameter in the ability to detect other aircraft. Unfortunately business jets and general aviation aircraft are on the "small" side of this spectrum and thus would be very difficult to see at sufficient distances to avoid a collision.

Detecting a target at jet speeds leaves very little time to see and avoid. For example, a jet descending at roughly 400 knots groundspeed covers 1.39 nm in 12.5 seconds. Let's say that the intersecting general aviation aircraft is on a roughly perpendicular flight path, thereby presenting more surface area to be detected and making it easier to see. Both the visual angle and its rate of change remain very small until imminent impact. At seven seconds to impact, a 40-foot-long aircraft would subtend only a 0.5-degree angle, which is still very small.

Walton Graham and Robert H. Orr, in a research paper entitled "Separation of Air Traffic by Visual Means: An Estimate of the Effectiveness of the See-and-Avoid Doctrine" and published in Proceedings of the IEEE (Volume 58, 1970) stated, "As speed increases, the effectiveness of 'see-and-avoid' greatly decreases. It is estimated that see-and-avoid prevents 97 percent of possible collisions at closing speeds of between 101 and 199 knots but only 47 percent when the closing speed is greater than 400 knots."

Morris continues, "Pilots can find it physically impossible to see converging traffic, especially when climbing or descending. Also, because human information processing is biased toward detection of contrast and sudden change, the small, motionless, camouflaged target projected by a rapidly converging aircraft is difficult to detect within the random and narrow window of opportunity to see it."

The human visual system is particularly attuned to detecting movement but is less effective at detecting stationary objects. Unfortunately, an aircraft on a collision course will usually appear to be a stationary object in the pilot's visual field. From each pilot's point of view, the converging aircraft will grow in size while remaining fixed at a particular point in the windscreen.

FAA Advisory Circular 90-48C recommends scanning the entire visual field outside the cockpit with eye movements of 10 degrees or less to ensure detection of conflicting traffic. The FAA estimates that approximately one second is required at each fixation. Thus, to scan an area 180 degrees horizontal and 30 degrees vertical could take 54 such fixations at one second each. A jet descending at an approximate groundspeed of 360 knots would cover roughly six miles per minute, so a pilot who faithfully follows the procedure exactly as spelled out in the Advisory Circular would see an entirely different kind of scene before completing the scan. Marthinsen has a rather negative opinion of the FAA scanning technique, stating, "It is incompatible with the physiological capability of the human eye. The time it would take to scan is substantially longer than the time available to see-and-avoid in many of the midair collision accidents."

Do pilots practice the recommended scanning pattern? According to research cited in the Australian Transport Safety Bureau's report, "Visual scans tend to be unsystematic, with some areas of the visual field receiving close attention while other areas are neglected. Areas of the sky around edges of the windscreens are generally scanned less than the sky in the center, and saccades [motion of eye between fixations -- Ed.] may be too large, leaving large areas of unsearched space between fixation points."

Furthermore, researchers have known for many years that in the absence of visual cues, the eye will focus at a relatively short distance. In an empty field such as a limitless blue sky, the eye will focus at around 56 centimeters (1.8 feet). This effect is known as "empty field myopia" and can reduce the chance of identifying a distant object. Because the natural focus point is around a half meter (1.6 feet) away, it requires an effort to focus at greater distances, particularly in the absence of visual cues.

A U.S. study in 1976 found that private pilots on VFR flights spend about 50 percent of their time in outside traffic scan during cruise flight, although this drops off to 40 percent during departure and approach. Even motivated pilots under ideal conditions frequently fail to sight conflicting traffic. A research project conducted by John W. Andrews of the Massachusetts Institute of Technology's Lincoln Laboratory involved 24 general aviation pilots flying a Beech Bonanza on a VFR cross country. The pilots were not aware that their aircraft would be intercepted several times by a Cessna 421 flying a near-collision course. The pilots spotted 36 out of 64 encounters, a 56-percent detection rate. Keep in mind that this study involved comparatively low-speed traffic operating under ideal detection conditions. The MIT study concluded that the ability of pilots to detect aircraft on near-collision courses is not great.Capt. Harry Orlady, a well-respected human factors researcher and former United Air Lines pilot, published a paper with the National Research Council estimating that airline pilots spend about 20 percent of their time in outside scan. A United-ALPA study of airline crews determined that "no one is looking during climb at least 62 percent of the time and 52 percent of the time during descent."

cont'd

[gaunty]

Part the twoth
Earl Wiener, Ph.D., professor of management science and industrial engineering at the University of Miami, Florida, found that pilots whose aircraft are equipped with glass cockpits spend more "head down" time, particularly at low altitudes, as they interact with their flight management systems. These findings were also confirmed in a study (written by yours truly) published in the Transportation Research Record, a peer-reviewed journal of the National Research Council. That study concluded that pilots of automated cockpits, especially during high workload periods in terminal airspace, had a lower likelihood than pilots flying "steam gauges" of detecting aircraft on a collision course.
The increase of inside-the-cockpit duties (such as programming FMSes, running checklists and adjusting systems) has an additional negative effect on the see-and-avoid principle. The human eye is brought into focus by muscle movements, which change the shape of the eye lens. It takes time for the eyes to refocus from viewing objects inside the cockpit to those outside. This process is called "accommodation."
A young person will typically require about one second to accommodate to a stimulus; however, the speed and degree of accommodation decreases with age, which is a separate issue from the general degradation in visual acuity that often occurs with aging. Of further concern is the increased time required for accommodation as a pilot becomes fatigued.
The average person has a visual field of about 190 degrees, although field of vision varies from person to person and is generally greater for females than males. The field of vision begins to contract after age 35, and in males, this reduction accelerates markedly after 55 years of age.
A number of transient and psychological conditions such as vibration, fatigue, hypoxia or, more than likely, cockpit workload can cause the effective field of vision to contract even further. Experiments conducted at the NASA Ames Research Center indicated that a concurrent task could reduce pilot eye movements by up to 60 percent.
The small visual angle of an approaching aircraft may make it impossible for a pilot to detect the aircraft in time to take evasive action. Since thin wings on aircraft such as gliders are almost invisible when viewed from ahead or behind, such an aircraft must approach even closer before it presents a target of detectable size. In a special study conducted by MIT's Lincoln Lab for the NTSB's investigation of the 1986 Cerritos accident, the estimated probability of visual acquisition of a general aviation aircraft with one pilot looking out the cockpit is just under 20 percent at a range of just one mile.
Further limiting the ability of pilots to see and avoid is the design of flight deck windows. Most cockpits severely limit the pilot's field of view. Obstructions to vision can include window posts, instrument and annunciator panels, glareshields, sun visors, eyeglass rims, windscreen bug splatter, windscreen imperfections, wings and the pilot beside you. Obstructions will not only mask some of the view completely, but will result in certain areas of the outside world being visible to only one eye, making it less likely to be detected. The eye has a natural blind spot at the point where the optic nerve exits the eyeball. Under normal conditions of binocular vision, the blind spot is not a problem as the area of the visual field falling on the blind spot of one eye will still be visible to the other eye.
However, if the view from one eye is obstructed (such as by a window post), then objects in the blind spot of the remaining eye will be invisible. Bearing in mind that an aircraft on a collision course appears stationary in the visual field, the blind spot could potentially mask a conflicting aircraft. The blind spot covers a visual angle of about five degrees horizontal, which is roughly 18 meters (59 feet) at a distance of 200 meters (656 feet), or enough to obscure a Hawker. A second undesirable effect of a window post or similar obstruction is that it can draw the point of focus inward, resulting not only in blurred vision but distorted perception of size and distance.
When the size of a target becomes large enough, a pilot may see the target, if he is looking directly in that direction. Assuming a pilot has adequate visual acuity and adequate vision outside of the cockpit, there are still many reasons limiting his ability to see another aircraft on a collision course. Detecting traffic can be difficult because aircraft usually appear against complex backgrounds of clouds or terrain. The human eye is very attuned to detecting borders between objects, but in the absence of contours, the visual system rapidly loses efficiency.
So would painting all aircraft bright orange help pilots spot traffic? Not really. The color of an aircraft is less important than the aircraft's contrast, that is its difference in brightness with its background, and it's one of the major determinants of detectability. Contrast also involves reflectivity, background complexity and atmospheric visibility. A good example of contrast is the black letters on a white eye chart. With good lighting the letters can be easily observed in a doctor's office. However, out in the real world, identifying a target is much more difficult when an aircraft is viewed against the background of a city. A dark aircraft will be seen best against a light background, such as bright sky, while a light-colored aircraft will be most conspicuous against a dull background such as a forest. Contrast is further reduced when small particles of haze scatter light. Not only does haze scatter some light away from the observer, but it also scatters some light from the aircraft so that it appears to originate from the background, while light from the background is scattered into the eye's image of the aircraft.
In addition, glare can come directly from the light source or can take the form of veiling glare, reflected from crazing or dirt on the windscreen. Furthermore, a pilot's age will affect his tolerance for glare. In general, older pilots will be more sensitive to glare.
TCAS was obviously motivated by the tragic accidents stemming from the limitations of the see-and-avoid concept. Those who have flown with TCAS know what a tremendous tool it can be. A common anecdotal observation by many colleagues is that without TCAS, they would miss the majority of traffic that would approach their aircraft at a close range. Human factors research noted by the Australian Transport Safety Bureau found that a traffic search in the absence of traffic information (i.e., no ATC alert, no TCAS TA) is less likely to be successful than a search where traffic information has been provided because knowing where to look greatly increases the chance of sighting the traffic. In fact, traffic alerts were found to increase search effectiveness by a factor of eight.
Providing additional evidence to the efficacy of TCAS-like advisories was the MIT Lincoln Laboratory study cited earlier. The same pilots in the study were given "TCAS-type" advisories as a second part of the research project. In this trial, 57 of the 66 encounters were acquired visually (as opposed to 36 out of 64 encounters without the TCAS-like advisory), with the median range of acquisition being 1.4 nm.
Has TCAS II been a successful factor in preventing collisions? Absolutely. In fact, TCAS II was cited as a factor in detecting and avoiding further loss of separation in 78 percent of reported NMACs in a recent 10-year period. Fifty-nine percent of the reported NMACs involved a resolution advisory from a TCAS II. However, like any warning system, it could not be designed to be absolutely effective in every situation. Fifteen percent of the business jets involved in NMACs were not equipped with TCAS II. In 8 percent of the ASRS reports, the "target aircraft" was not ordinarily equipped with an altitude encoding transponder. TCAS will not provide maximum protection from inflight collisions unless and until all aircraft are equipped with Mode C transponders or its equivalent.
Given the many limitations of the see-and-avoid concept, what must be done to ensure sufficient separation between high-performance and light, general aviation aircraft sharing the same airspace? Arguably, a multilayered protective system is needed in case one or two layers fail, and by design it should offset the fallibility of the see-and-avoid concept. This conclusion isn't my opinion, but rather stems from recommendations from respected organizations and authorities. The Australian Transport Safety Bureau's report stated, "Unalerted see-and-avoid has a limited place as a last resort means of traffic separation at low closing speeds, but is not sufficiently reliable to warrant a greater role in the air traffic system. Australia's Bureau of Air Safety Investigation considers that see-and-avoid is completely unsuitable as a primary traffic separation method for high-speed jet traffic."The separation of high-performance traffic from low-performance traffic has been previously suggested in the United States. In the aftermath of the MU-2/PA-32 accident near Greenwood, Ind., the NTSB suggested that "consideration should be given to establishing entry and departure corridors for high-performance airplanes that are separate from low-performance airplanes at uncontrolled airports."
Airspace separation would be just one layer in a multilayered remedy. "While visual scanning is necessary to prevent midair collisions, it is not sufficient," said the DOT's Morris, who continued, "Potential mitigation strategies include reliable altitude encoding transponders activated at all times in all aircraft, and affordable and reliable collision avoidance technologies in all general aviation aircraft, as the NTSB recommended in 1987."
In today's era of GPS precision, digital cockpits and synthetic vision, the fact that we still depend on the old, fallible "Mark VIII eyeball" to avoid midair collisions is confounding and dangerous. The rate of inflight collisions isn't likely to improve markedly until we get serious about implementing technological and procedural remedies to address this serious, continuing hazard.

[Scurvy.D.Dog]

.... and the clock keeps ticking :(
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... CTAF and RPT's should not mix, and Class E should not exist below A125 in climb and descent areas(you know why)!
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.... election looming ... I wonder when we will 'publicly' hear of the next push to appease his greatness :yuk:
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....just when you though it could not happen AGAIN .... well ... watch this space :mad: