Lockerbie navigation ?

[Argonautical]

Last week I watched a program on UK TV history about aviation terrorism and it featured the Lockerbie disaster. My question is, what was a plane flying from London to New York doing over Lockerbie ? Is it something to do with the great circle route and the earth's rotation?

[helicopter-redeye]

1. Great Circle Routes (going round a sphere is not a straight line experience)

2. Organised Track System (North Atlantic Track System). It may have had a high lat track allocated

[Rainboe]

Common routing for transatlantic traffic from London is over Glasgow and out over the Hebrides. If a more southerly routing is required, the exit is over south Wales and southern Ireland. If you want to see why this is so, stretch a piece of string between 2 points on a globe and see how it behaves.

[BALIX]

Great circle? Yes.

Earth's rotation? Yes also, oddly enough, though indirectly. The earth's rotation is, I believe, responsible for the jetstreams, the winds that blow at the levels at which aircraft fly. These move along quite rapidly in a relatively thin band, from west to east. Consequently, an aircraft flying from New York to London wants to be in them as they will increase the groundspeed and thus reduce flight time. Conversely, an aircraft going the other way will want to avoid them. That is why transatlantic flights take longer westbound than they do eastbound.

The position of the jetstream alters from day to day so the airlines will request routings based on the forecast winds (and, of course, the great circle routing). Some days a London-New York flight will fly out over Lands End, others it will pass over the Hebrides. On the night of the Lockerbie disaster, the jetstreams must have been to the south so the Clipper headed north to avoid them. It was, I believe, due to enter oceanic airspace at 57N10W which is quite far north for a London-New York flight, though not exceptional.

[retiredandloveit]

I agree with the posts (as an observer not a professional) outlining the great circle routing and winds regarding the positioning of Clipper 103. An additional element in the fact that the aircraft came down over Lockerbie I believe is that it was behind time. The explosion was planned to occur over the ocean similar to the Air India 747.
A question though regarding track miles v winds.
On 30th September I flew from Paris to Boston on an Air France A340. According to the cabin flight route display we travelled in a straight line across the atlantic which surprised me. On the return journey we did travel what I thought was the more conventional route up the coast of Nova Scotia South of Greenland and eventually overhead Jersey into French Airspace in what I took to be a great circle route (bearing in mind the previous info about east/west winds). Why the difference?
The common sense answer seems to be that the primary consideration is wind but as there may be factors of which I know nothing eg traffic density, routing reqirements can anyone shed a light?

[Rainboe]

The jetstream is a wide band of high speed wind. Across the Atlantic, it blows from the west and hitting Europe tends to be a little more southerly. Flights to the west try and goaround the less strong northern part of the Atlantic, frequently even as far as the south of Greenland, and even further north if heading to the US west coast or Canada. Eastbound, you want to be in the centre of the jetstream and benefit from tailwinds anything up to 200kts. SO a common route back to Europe is over Land's End or southern Ireland.
You can do a wealth of research on Jetstreams- Google's yer friend.

[HEATHROW DIRECTOR]

retiredandloveit.... Initial routeings before entering oceanic airspace will depend on the national airways structure for the countries concerned. The track across the pond itself will vary depending on the routes which have been designated for a particular day taking account of the winds, as mentioned earlier.

[Golf Charlie Charlie]

Argonautical's question is also one that has puzzled me a little for years.

Yes, I too know all about oceanic tracks, great circles and jetstreams etc.

I have flown literally hundreds of times between London and New York in the past 25 years. I have never knowingly flown outbound or inbound that far north. The most northerly tracks have tended to be over Northern Ireland and the Lake District. The majority (at least 90%) go no further north than Liverpool/Dublin and about half over south Wales/southern Ireland.

True, in earlier days before in-flight moving maps there would be some tracks I wouldn't know or recognize, but I do think a Lockerbie/Glasgow track to New York is unusual. I guess it was just a coincidence. Obviously more normal for flights further west in North America.

[holyflyer]

I was dropping some people out to Heathrow and actually saw Clipper 103 take-off from LHR that night. Weather wise I seem to remember that a south-westerly gale was blowing in. This probably necessitated the northerly routing.

In my trips across the pond I have been on a London - Boston that went out over Macrihanish and a London - Toronto that went north from Glasgow. Furtherest north was a London - Vancover which eventually flew across northern Greenland.

Quickest and bumpiest eastbound was a BA 747 MIA - LHR done in something like 6 hours - we must have been in the jetstream the whole way - a real rollar coaster, seat belts on all the way. All went well to OCK then we spent at least an hour in the hold at OCK as everybody else from US had arrived together. Mayhem in the baggage hall as a result.

[BALIX]

I was working the night of the Lockerbie disaster - in fact I was doing the sector through which it fell (ScACC Talla sector) along with a colleague.

Like I mentioned before, a routing that far north for a London-JFK flight is unusual but it does happen from time to time that the oceanic tracks are really quite a long way north. There are usually six tracks, each separated by a degree of lattitude (=60nm). I have seen 57N10W as the most southerly track before.

Not all transatlantic aircraft use these daily promulgated tracks but the majority do.

[pax britanica]

I have also done too many Transatlantics as a pax to remember all of them but one does stick in my mind. LHR to Bermuda on a 1011-500 which went up over Macrihanish. This to the astonshment of many pax when the captain pointed out the beautiful view of the western isles since the normal route was via Lands End . Trip took best part of ten hours routing over Iceland and Nova Scotia and south to BDA. Bermuda is both east and south of New York so thats an even more extreme favourable wind routing than LHR to JFK on the same sort of track. Again it was very very strong winds as the inbound flight from Bda to Lhr three days previously had done the trip in 4 hrs 58 and as an earlier poster wrote-very very very uncomfortable.

I was in Bermuda when the Lockerbie disaster occurred and a business colleagues son was booked on it but missed the flight -such is fate. It did occur to me at the time that the murderers who committed the crime actually had some knowledge about aviation and assumed the bomb going off say 45 mins to an hour after take off would cause the plane to crash pretty much without trace into the Irish sea or Atlantic. Because it came down on land it did mean the investigators were able to find the subtle clues that eventually lead to tracking down the killers-not sure they would have had much success with explosive residue traces and fragments of baggage had it crashed south of Cork for example
PB

[retiredandloveit]

Heathrow Director, Thanks for that. It seem that in spite of all of our modern technology ( For which I for one am immensley grateful as an old codger who can get about a bit) we are still to some degree ruled by nature - perhaps Drake and Nelson would have had a secret chuckle!

[HEATHROW DIRECTOR]

<<For which I for one am immensley grateful as an old codger who can get about a bit>>

You and me both and long may it last....

[chiglet]

Depend on Destination...[Sometimes]
The past few days at Manch...
Atlanta WAL dep Manch DUBlin...go
Chicago POL GLAgow... go
Las Vegas POL StorNoway... go
Caused by "Winds over the Atlantic",,,Sometimes "inbound to Europe" the track is over Scotland...other times its over Cornwall [or even further south]
watp,iktch

[WHBM]

I don't think the expectation that the aircraft would have been out over the Atlantic on a more usual track is correct, as it would still have been over Ireland on a normal day.

Like many transatlantic flyers over the years, I've noticed a wide variety of tracks. There was a time some years ago when on LHR-MIA we went over Newfoundland more often than not. More recently some more geographically direct routings seem to apply. ETOPS is nothing to do with this, and the Pan Am was a 747 anyway.

Like many here it seems, I can recall the Lockerbie day. I was passenger on a BA 747 LHR-LAX which took off some hours before, so of course being on board we knew nothing. On arrival at LAX it was something that had happened to a flight not connected to there, so not an issue. Back in the UK however all hell had broken loose with my colleagues and relations. This is where you discover all sorts of myths, like "there's only one plane a day to America", or that I "always go with Pan Am" (in fact I never ever used them).

It wasn't helped by the fact that the flight number was, IIRC, through LHR-JFK-LAX, and also I believe the flight deck were from the Pan Am LAX base, as I recall when their details appeared in the press they had Southern California addresses. This probably led to some misreporting in the UK that it was headed to Los Angeles.

It was a few days before Christmas and it had been difficult even a month beforehand to get seats. Of course my flight, as most other transatlantics that day presumably, was full. I have always wondered why the accident aircraft was only just over half-full.

[Golf Charlie Charlie]

<<<
I have always wondered why the accident aircraft was only just over half-full.
>>>

There has been speculation in the past that some elements of the American community in the UK had been tipped off about a possible attack on a US airliner out of London just before the Christmas holidays that year. For the first time some Americans, especially in the diplomatic/governmental corps, had been quietly advised to use non-US airlines to go home with for the Christmas/New Year holiday.

Now, I stress I am not endorsing this theory myself - but it is something that I heard both at the time and occasionally in the years since.

[BRL]

Interesting thread this. Does anyone have a link to a map with the tracks on it?

[BALIX]

Just out of interest, saw both those new business class only services from STN to JFK enter oceanic airspace at BALIX (59N10W, not me..) today, though I suspect that is more to do with ETOPS than any other factor.

[Kestrel_909]

Live in N.Ireland and you get a nice view of things heading for the Ocean.

Anything coming along UP6 and entering at MIMKU is within eyesight of my home, more often than not it's directly overhead me, though the past few days it's been rather quiet and I've heard them go out via NIBOG over and over again.

Always found it quite interesting in the different flights passing overhead me from all over Europe heading to all over North America, at some point or another (sad I know:( )

BRL,
You'll find a little program here called NATPLOT that you can get the tracks to show on though I've never used it.
http://www.natroutes.glideslope.de/

http://gc.kls2.com/ is also quite handy site for interest

[skiesfull]

PanAm 103 was a delayed flight from LHR. It would therefore have filed a flight -plan for a 'random track' across the Atlantic. The Organised Track System - OTS would then be eastbound and PA 103 may well have filed a more northerly track ( not so unusual) to avoid conflict later on and eventually climb to its' optimum altitude with few restrictions, or the PanAm planners may have tried to get a routeing in the least-effective headwind.
The model used by flight planners depends on the airline, but usually takes into consideration, such variables as headwind/tailwind and military/political constaints. The fixed factors are organised tracks ( not only the Atlantic), fixed Mach number technique -used for spacing and some other factors such as high safety altitudes and oxygen requirements. Despite having selected the fastest flight time (and therefore the least fuel required/ most economical) this may not be the route used - maybe a hurricane/tropical cyclone/typhoon on the way. Also the track requested may not be available/ or altitude/ or speed, due to congestion. No-one said it would be easy!!

[holyflyer]

I do seem to remember that when the Canadian ATC were on strike (probably 15-20 years ago) an Aer Lingus 747 going to JFK headed east out of Dublin, across WAL then to Ottringham. If memory serves me correctly it then headed up to Norway across the very north of Greenland and down to JFK by way of Alert, Resolute, Churchill and Thunder Bay. Certainly the long way round. (The southerly tracks via the Azores being fully booked from other departure points)