Offsetting - time to make it official just about everywhere

[410]

I see that the in the remarks that follow the daily NAT tracks details now say:

"CREWS ARE REMINDED THAT WITHIN NAT REGION, THE STATEGIC LETERAL OFFSET PROCEDURE, SLOP, SHOULD BE USED AS A STANDARD OPERATING PROCEDURE AND NOT SOLELY FOR TURBULENCE/WEATHER AVOIDANCE". (My boldface.)

Anyone caring to do a search through my posts will see that I've been a lone voice in the wilderness for quite some years now pushing for offsetting for all enroute flying.

So given that the NAT authorities now seem to have seen the light and acknowledged that offsetting does increase safety and should be used at all times in NAT airspace, is it time for us to start calling for it to be used everywhere avove (say) 20,000' - ideally as a built-in feature of our FMCs?

It's not as though we have to wait for an accident that results in major loss of life to occur to prove how incredibly overdue this SIMPLE change in procedures is - it's happened already, and not just once. The recent tragedy in Brazil is just the latest example of a disaster that would have been nothing more than an airprox report - (and maybe, with ignorance being bliss, not even that!) - had both aircraft's FMCs had a built-in 1/2 mile offset whenever they were in LNAV and above 20,000'.

[cribble]

Concur, with the proviso that the technique should not be used on User Preferred Routes or Random Routes ie only use the technique on airways or on designated routes (eg NAT TRK or similar).

[TwoOneFour]

So given that the NAT authorities now seem to have seen the light and acknowledged that offsetting does increase safety and should be used at all times in NAT airspace

From what I understand offset flying has been available as an option on NAT tracks for some time, and the NAT authorities, far from "seeing the light" were actually bitching last August (nearly a year ago) about the lack of take-up from transatlantic crews, only one in 10 of whom were bothering to offset when two alternative tracks - 1nm and 2nm to the right - were open and available. These stats were circulated within NATS and through other outlets.

If the offset option's been available on NAT tracks all that time, surely the question is: Why aren't crews doing it?

[Basil]

Perhaps they think it's carbon offsetting

[BelArgUSA]

I support the concept... however only if in RVSM/MNPS airspace and no need to do 2 or 3 nautical miles... 1 mile is enough... I fly from South America to Europe, and often tempted to change the last digit of longitude to get an offset... to the right...
xxx
We have triple INS (LTN-92) with 2 GPS updating, in our old 747-200s, so it is still time consuming to enter such corrected data without errors...
xxx

Happy contrails

[410]

If the offset option's been available on NAT tracks all that time, surely the question is: Why aren't crews doing it?

Because, in from experience, many simply can't be bothered, which is why I believe it should be built in to our nav systems.

For those who want revervations, (as some have already stated in the first few posts), consider the accuracy of the current IRS/GPS systems - for instance, how often do you see opposite direction traffic NOT go exactly over or under you? - and then consider how wide an airway is. Even with an offset built in, the aircraft is going to be well within the confines of the airway.

For those with reservations, my suggestion is that the offset should 'kick in' only in RNAV, and, I'd suggest, only gradually after (say) four or five minutes or maybe even longer in that mode. If the aircraft is being vectored by a controller, it goes onto the heading called for and stays there, and if the aircraft is cleared "direct to" a waypoint after being radar vectored, I can't see a gradual introduction of a 1/2 mile offset after the first few minutes back in RNAV mode is going to make any difference to separation.

Even if it does require some ATC procedures to be modified to provide the separation demanded by the mathemeticians, surely the increase in safey margins would be worth it.

Separation can be lost sometimes, for any number of reasons, as was illustrated all too clearly by the Brazil disaster as well as a number of other earlier collisions.

I simply can't understand how few of us who fly what are quite literally speeding bullets continue to be happy, (some might say apparently blithely unaware), about having a lot of other speeding bullets flying in exactly the same vertical plane as we are when a few lines of computer code (and some legislation) would automatically put those other speeding bullets into a completely different vertical plane.

This one step would decrease the chances of two passenger-laden speeding bullets hitting each other by an enormous degree should human error (be it a pilot's or a controller's) and/or some other problem allow a mistake to me made as it would seem was made in Brazil.

[eyeinthesky]

QUOTE
From what I understand offset flying has been available as an option on NAT tracks for some time, and the NAT authorities, far from "seeing the light" were actually bitching last August (nearly a year ago) about the lack of take-up from transatlantic crews, only one in 10 of whom were bothering to offset when two alternative tracks - 1nm and 2nm to the right - were open and available. These stats were circulated within NATS and through other outlets.
UNQUOTE

Of course, if everybody offsets by the same amount, there's no point in doing it! It just moves the problem a mile or two to the right.

(Offsetting to the right will protect against opposite direction traffic but not same direction)

[TwoOneFour]

Of course, if everybody offsets by the same amount, there's no point in doing it! It just moves the problem a mile or two to the right.

That's missing the point entirely in my opinion - the NAT tracks offer 1nm and 2nm offset which, when you consider the centreline track as well, gives crews three options.

On average, you ought to have a situation where the traffic density is spread across three tracks, reducing the collision risk.

No-one's saying everyone has to offset. What's being offered is the chance to lessen risks by having two-thirds of crews follow something other than the centreline. Instead 90% of crews are still going straight down the middle.

[411A]

Hmmm, seems to me that if a 'built in' offset was on some aircraft with new(er) kit, and not others, one would have the requirement for RNP 0.3 thrown out the window with the bathwater, and the whole idea would be a total and complete waste of time.

First it was....we aren't accurate enough (Navigators), then it was...we need something better that basic INS, and now it's...we are too accurate, so offsets are needed and should be mandatory.

Poppycock, I say...stick with the plot and fly the aeroplane on the airway centerline, instead of adhoc nonsense.

[Shaka Zulu]

Right common sense:

No Rdr over Siberia: Offset 1R or 2R
Aircraft ahead 1000' above your Lvl and closing him down: Offset 1R due turbulence
Africa: Always SLOP, dangerous territory
NATS: Only SLOP when other Aircraft are ahead and above/consider losing an engine and having to turn of the tracks....

[Wiley]

Why am I not surprised to find that our old mate 411A is a 'straight down the airway centreline' (sorry, 411A, centerline) man.

...and TwoOneFour, I think you'll find that 410 is indeed saying that everyone should offset 1/2 NM so that (not in the usually one way NAT airspace, but in the rest of the world), no one will be on the centreline on a two way airway.

[ARINC]

I support the concept... however only if in RVSM/MNPS airspace and no need to do 2 or 3 nautical miles... 1 mile is enough... I fly from South America to Europe, and often tempted to change the last digit of longitude to get an offset... to the right...
xxx
We have triple INS (LTN-92) with 2 GPS updating, in our old 747-200s, so it is still time consuming to enter such corrected data without errors...
xxx
Happy contrails

Hi BelArgUSA your post intrigues me....do you have to manually enter offset waypoints ?? Only have experience of of -400 so not familiar with your FMS fit.

[PPRuNeUser0183]

I disagree that the offset should be integrated, that's going to lead to all kinds of confusion surely (when would the aircraft return to the AWY centre-line? This would be uncommanded presumably - most disconcerting!)

I presume this discussion came about after the article in Flight a month or so ago. It's been published in the track message for ages, and most seem to ignore it. Personally, I see no reason to offset unless there's other traffic around flying at a different speed, and in any case, try to return to the C/L by the exit point.

Curious.... do any of you consider this when it comes to your preference turning off track for an engine failure/drift down? Look out!!

Should there be a standard procedure according to the crosswind component as to which a/c offsets??

[Fubaar]

Most people who've replied seem fixated on the North Atlantic. I understood 410 to be saying it should be introduced everywhere else as well, where most airways are two way and a half mile offset would set opposite direction traffic apart by one mile, (which would have saved the pax and crew of the 737 in Brazil).

Personally, I can't understand the resistance to the idea. I'd much rather see opposite direction traffic fly past me to one side than right over or under me.

What's the problem of being a half mile from overhead the aid when flying overhead IF YOU"RE ABOVE FL200? With 410's suggestion, the offset wouldn't be activated if you were below 20,000', like when you were doing an approach, the only time it would matter a damn if you're absolutely overhead the aid or a half mile to the right of overhead.

[GMS]

411A,

May I sugest you read about the near encounter between a Turkish Airlines Airbus and a canadian Airbus on a NAT track. This might change your views.

GMS

[338C]

Offsetting-Cheap Risk Management

Offsetting is particularly advantageous on two way routes as it ensures that aircraft passing head on are at least 1 NM laterally separated.

On NAT tracks it can minimize wake turbulence from overtaking aircraft.

Random tracks across the North Atlantic are similar to two way routes as the same route can be planned for an east or west bound flight and when offsetting is utilized protection as previously mentioned is provided.

There is a safety case to be made that anything a pilot can do to strengthen defenses in the ATC system the less likelihood of lapses and omissions resulting in an incident or accident. Offsetting strengthens the ATC defense system. Operational crews are the direct beneficiaries.

Consider deciding prior to take off that offsetting will be utilized and whether it will be 1 nm or 2.

[BelArgUSA]

Lateral or... even vertical offset...

I have been absent from NAT tracks since 2004, so I cannot open my mouth about that airspace... I fly the South Atlantic routes South America to Europe with permanently published tracks between North East Brazil (Recife/Natal/Fortaleza) to the Sal/Cape Verde and Dakar FIRs, where permanent tracks are published. Very few random tracks are in use...
xxx
As far as flying Africa, from the Southern Border of Algiers FIR, until reaching the Johannesburg FIR, I had some crossings of entire FIRs with NO ATC conracts whatsoever. ACC controllers in Chad, Central African Republic, or Zaire-Congo were... alseep, or unplugged their VHF or HF radios from the only outlet to warm-up the water for tea or coffee... or watch TV... In these areas, I often had the urge of being 200 feet above or below assigned level...
xxx
For ARINC - the big problem with our prehistoric 747-200s, is that they have no FMS... After initial positioning of the LTN-92 INS units, we XFILL waypoints to waypoints manually to the other 2 units. Works great, accurate and no problem for lateral NAV, update by GPS... In the past, before the GPS update, it was DME update... But VNAV functions are inexistant... So the autopilot will track with accuracy, but climbs or descents require human brains for planning. The 747-400s are an entirely different breed... You are lucky...
xxx

Happy contrails

[410]

338C, perhaps if I'd phrased my first post even halfway as clearly and succiently as you did your contribution to this thread, more people might have been able to understand my suggestion.

I liken our current enroute procedures with ultra accurate GPS and IRS navigation equipment to walking down a rifle range (for eight or twelve hours at a time!) exactly under the firing line of a constantly changing, highly trained(?) team of marksmen firing a bullet over my head every five minutes, and trusting that the constantly changing marksmen will always fire over my head.

In 9999.9% of cases they assuredly will, but once in while one might let his point of aim drop.

...and, (if I must walk on the rifle range), if I took the simple 'belts and braces' precaution of always walking one pace to the right of the very accurate firing line, I'd always be out of the line of fire laterally as well as vertically.

It's not rocket science to see that this has to be a safer procedure than sticking to the centre of the airway.

[FE Hoppy]

I agree that SLOP should be used whenever possible. Of course all offsets should be cancelled when aproaching the first waypoint of a published procedure.

Rather than building in a fixed offset perhaps a random innaccuracy when operating in RNP > 1 airspace?

Just a thought.

[Andu]

If the posts so far on this thread are anything to go by, any such measure would have to be something built in to the system and out of the individual pilot's hands completely, for it would seem that everyone who thinks it's a good idea has his own ideas on how and when it should and shouldn't be done.

And I suspect the vast majority would continue to do nothing unless it was done for them. This says a lot about the trust most of us put in an ATC system that has been proven in a couple of very high profile cases to be overloaded and sometimes flawed.

What's going to be really interesting is if the findings in the Brazil tragedy (or some future midair tragedy) say the accident could have been avoided if a policy of NOT flying on the airway centreline had been introduced worldwide some years ago - as some professional pilots, like "410", have been calling for here on Pprune from the earliest days of the site. (I can remember reading "Lessons from Delhi", [that called for offsetting], on the PPrune Home Page many years ago now, Danny, if available bandwidth allows it, maybe you could consider putting that back on the Home Page where people can read it.)