Transatlantic flight question--diversion?

[Monica]

Hello,

I was very glad to stumble on this site, both for support from other fearful flyers and for expert advice from generous pilots. Thanks to the organizers for keeping this running!

One way I try to reassure myself when flying within the US is by reminding myself that there are many airports in the flight paths and so it wouldn't be hard for the plane to divert or seek help in the event of a problem. Now I have an upcoming flight from Boston to the UK planned for professional reasons, and that method of reassurance isn't helping at all, since I can't see how one would divert when halfway across an ocean. If it was necessary to divert a plane midway through a transatlantic flight, how would you go about doing so?

Thank you very much!

Monica

[MathFox]

Firstly, most diversions are caused by bad weather at the destination airport or capacity problems and it isn't too difficult to find another UK airport which states "weather conditions are nice"

Secondly, the planes that cross the Atlantic are either 3 or 4 engine planes or dual engine planes that are certified to fly for a few hours on a single engine. There are airports with long runways on Iceland, the Azores and in Canada and Ireland near the coast. Your captain will have reviewed them as emergency diversion options.
In the exceptionally rare case that all engines fail, a modern jet can glide a considerable distance (50-100 miles from cruise altitude to sea level) and land safely. The Air Transat that lost all its fuel over the Atlantic made a safe landing at Lajes (Terceira).
As last resort... a plane can land on the water. I recall no recent airline incidents where that happened. The nice thing of a water landing is that there are no trees, fences or buildings to crash into. You will have a life jacket and the evacuation slides act as life rafts.

British nice weather -> you don't need an umbrella for the walk from the plane to the gate; however it might be more comfortable with an umbrella.;)

[Falcon]

The first thing to get out of the way is how many engines. A BA 747 ( four engines ) lifted off in the US and had an engine failure. They carried on and landed in Manchester to re fuel.

Two engined aircraft such as 777 757 etc have to follow rules called EROPS (Extended range ops) they have to stay a certain distance from land ( 40 mins flying time on one engine I think ).

From Boston you will have.... Canada, Iceland then Scotland and down. Dont forget aircraft can also turn round and go back.

Hope that helps/

[ThrottleHold]

I fly a twin engine aircraft on regular transatlantic routes, includng to and from Boston. We have to follow ETOPS (Extended range Twin engine OPeratoinS) rules. To qualify for ETOPS, the aircraft and airline must be certified to a certain standard.

Standard ETOPS allows a twin engine aircraft to fly up to 180 minutes away from a suitable diversion airfield. This time is based on the aircaft flying at its SINGLE engine long range cruise speed. If it was not ETOPS, it would have to stay within 60 minutes of a suitable airfield. From my experience, your are not likely to be more than 90 - 120 minutes away from the nearest diversion airfield while on your route.
Unless your aircraft is non-ETOPS, your routing from Boston will take you north-easterly over Nova Scotia and Newfoundland. From there it will join the NATS (North Atlantic Track Structure) on an almost straight track to Ireland. Since there is no radar coverage over the ocean, aircraft have to fly on these prescribed routings in order to maintain seperation from each other. There can be anywhere from 4 to 6 tracks each day, separated by no less than 60 nautical miles from each other. Aircraft are controlled on these from the Gander Oceanic Control Centre in Newfoundland (while west of 30' West) and Shanwick OCC in Ireland and Scotland (east of 30' West). They will issue track joining clearances to each aircraft which will include an altitude and speed to fly at and a time restriction on joining the track system. This means that aircraft on the same track will be always separated form each other by at least 1000 feet vertically and 10 minutes laterally. In order that ATC can monitor the position of aircraft on the NATS, we must make a Position Report via long-range HF radio every 10' of Longitude when out of radar coverage, i.e at 50' West, 40' West, 30' West and 20' West. This report is includes the time and altitude over the point just passed, the estimated time of crossing the next waypoint and then the position of the next waypoint after that.

An example would be:

Callsign 123 overhead 54' North 50' West at time 0320, Flight Level 390. Estimate 55' North 40' West at 0407. 55' North 30' West next.

In the unlikely event of a diversion, the crew will have several options to take. The usual nominated diversion airfields are Gander, Stephenville or St. Johns in Newfoundland, Keflavik in Iceland, Lajes in the Azores and Shannon in Ireland.
We mark on our charts points called ETP's (Equal Time Points). These are worked out by flight planning beforehand using the flights nominated diversion airfields. So, for example, an ETP is worked out for Gander and Keflavik. Before reaching this ETP, we will divert to Gander, once passed it, it is quicker to go to Keflavik. Further along, there will be another ETP for Keflavik and Shannon. Once we pass this point, it will now be quicker to continue to Shannon for a diversion.

After all that....onto your question about how to divert! There are about 3 ways to do this. Firstly, and the most preferable is to call the appropriate air traffic control centre and see if they can issue you with a direct clearance to your diversion point. However, due to the lack of radar and the fact that the NATS are very busy at times, this is not always possible.
The next option is to leave the track system. This is done by turning off your track to establish on a flightpath which is 15 miles north or south of your track and parallel to it. Once this is attained we then have 2 options. We can either climb or descend by 500 feet and from there divert towards our diversion field, or preferably, descend below 28,500 feet (which is the base of the NATS) and then divert to our new destination.

Hope this hasn't all been a bit too technical, but I think it helps to have a good understanding of what will be going on on your flight!

[Barb-SAN]

Wow, Thanks, Throttlehold, for that very understandable, and detailed technical explanation. There are quite a few people here who fly that route, so we really appreciate knowing more about how you pilots navigate, and divert when necessary. :)

[MathFox]

ThrottleHold, you make a routine transatlantic crossing sound boring for the pilots: passing two ETP points; a position report every 40 to 50 minutes and as highlight of the passage a "hand over" from Shanwick to Gander (or the other way around).
What are you doing to pass the time? ;)

[Lynda]

Thanks Throttlehold, It is great to have such a detailed explanation. I fly transatlantic a couple of times a year so it is great to have a pilot around who also flies transatlantic.

Perhaps one day you may find time to do a Transatlaitic trip report from a pilot's perspective???:):):)

[Falcon]

Thanks for that ThrottleHold not being EROPS myself it always helps to be reminded of the facts of the certification.

[ThrottleHold]

For anyone interested, the August edition of Airways magazine has a very good article about operating a trans-Atlantic Newark-Geneva flight from a pilots perspective.

[Barb-SAN]

I wonder how we could find this magazine? I checked online, and there was only a brief paragraph about that article, but no access to the article itself. Maybe you have to subscribe to the magazine? Or is it available at airports in the bookstores/magazine racks? Or is it an in-flight magazine? http://www.airwaysmag.com/channels.html?article_id=165&channel_id=16

[Lynda]

Barb,
I managed to get the whole article by clicking on the In flight tab at the top??
http://www.airwaysmag.com/channels.html?channel_id=5

[ThrottleHold]

That's not the article I was referring too. Here's the link to the August issue, but it doesn't have the full article.

http://www.airwaysmag.com/channels.html?article_id=165&channel_id=16