Private vs. Commerical over-water flight routes


#1

Hi, I was wondering why private planes like Gulfstreams ect. when flying to Europe or China or over seas they stay over land as long as possible, limiting the time they are over the water, yet commercial flights do not.

for example:
a GLF5 from LAX to China will fly up to Alaska and then across Russia, while a 747 just flies straight over the water.

Are the smaller jet engines more prone to failure or what is the reason?

Thanks!


#2

Bigger jets have bigger fuel tanks and longer range. Consider that more miles on a perimeter route means longer flight and burns up lots more fuel.

Passengers want the shortest, most comfortable flight they can get without creating marginal safety conditions. Airlines buy those big jets because they can fly long non-stop routes without compromising safety.

The GA jets, like the Gulfstream, either don’t have the range or their owners opt for a more certain level of operational safety.

Can you post a link showing a GLF5 flight from LAX to China?


#3

Just curious, what makes you think that the airlines would have a lesser standard of level of operational safety as compared to private companies or GA jet owners?

The above implies (or I read it this way) that the airlines would forego safety as compared to a private person or company to complete a mission???

Allen


#4

I see. Although failure of both engines is rare, maybe executives are willing to spend a couple of grand more to stay over land longer just in case of a over-water engine failure.

Whereas if a commercial carrier did that on every overseas flight, the loss in fuel costs would be much more than the insurance payout for persons injured in a rare emergency water ditch.

The most common case of this is all the flights from Tetterbero to Europe fly up through Canada then cross just below Greenland.


#5

Planes from LAX to China (and other USA-Asian) flights do normally fly near Alaska. If you take a string and place one end of it on, say, LAX, and the other end on, say, HKG, you’ll see that the shortest distance is an arc, not a straight line.

Take a look at these flights. Granted, they don’t show the entire route but you’ll be able to get the idea:
flightaware.com/live/flight/CKK2 … /KLAX/ZSPD
flightaware.com/live/flight/AAR2 … /KLAX/RKSI
flightaware.com/live/flight/AAL1 … /KLAX/RJAA
flightaware.com/live/flight/CSN3 … /KLAX/ZGGG


#6

Ah, now that’s a different case. On transatlantic flights, they have designated tracks that require minimum operational capabilities of the aircraft. Other aircraft need to stay out of this area and are therefore routed north or south of the tracks.

I don’t know the full specifics. I hope one of the airline pilots fly transatlantic flights could help with this.


#7

Less range?!? The G550 and the Global Express both have the capability to fly over 6500 miles! And no the “smaller” jet engines are no less reliable. And the CEO in the back usually has very little interest in exactly what route is flown unless it affects his/her schedule.

All aircraft with the range capability fly the North Atlantic Tracks if they are between FL290 and FL410. Above this, you can create a more direct routing, usually a great circle route. Below this are usually smaller aircraft that require multiple stops.

Keep in mind that airlines have to comply with ETOPS, Extended Twin-engine Operations, a systemthat ensures that there are multiple layers of safety (ie. no one mechanic may work on both engines to minimize the chances of a multiple failure from a flawed maintaince procedure). Based on the aircraft type, one may operate a certain number of minutes from a suitable divert airport, usually 120 or 180 minutes on a single engine.

Just the though of this makes my butt tired!

en.wikipedia.org/wiki/North_Atlantic_Tracks
en.wikipedia.org/wiki/ETOPS


#8

I think what coopdog is seeing is the difference between the airlines headed out on the organized tracks and the the business jets headed out random route going closer to great circle. The NAT tracks are organized each day to try and take advantage of winds but they are hardly close to great circle and not the most efficient way to cross an ocean. Since most airliners cannot climb above FL410 at crossing weights they are on the tracks. Most business aircraft have the performance at crossing weights to get FL410 and above and thus are free to random route along a near great circle path.
The Great Circle route from Los Angeles to Hong Kong does go way up north and almost passes over the the Aleutian islands.


#9

Go to the " Great Circle Mapper " and use KJFK and EDDF as your choice of airport. You with see the the prefered / shortest track actually parallels the NAT very closely.

The NAT varies day to day based on winds aloft and weather patterns as well as considerations for alternate landing sites. Sometimes St. John’s and Gander are foged in, so transatlantic flights are routes north closer to Goose Bay. So maybe not the most efficient, the NAT is there for safety and passenger comfort. The Jet Stream is one of the biggest considerations when creating the daily NAT. The “push” of the Jetstream offers more benefits to the airplane / pilot then just going the shortest distance would, so there are nights (mostly) when most commercial traffic will be routed well south of the ideal track, and in fact derive an advantage in fuel and time savings by not following the shortest route.

The track a plane takes varies depending on its operational requirements as well. Where as most commercial flights can do the transatlantic crossing without stopping, many cargo and corporate flights fly at weights that require them to refuel before they continue across the Atlantic. That is why Goose Bay, Gander and St. John’s see so much business in this respect.

As for the Pacific flights, as mentioned in previous posts, the prefered route is up through Alaska and back down past Russia and into the Asian market.

So to answer the over water route question, a straight line isn’t always the shortest route around a sphere, plus you have to add this safety consideration and destination requirements. and you see most commercial aviation following the same paths requardless of equipment.

An exception to this would be small single engine planes which have to hop accross the Atlantic or Pacific routes, fuel requirements force them to plan based on where the next / closest “gas station” is.

Just for reference, the NAT is directly over my house in NL on any given day, so I see this pattern on the North Atlantic route twice daily. Day time its Europe - NA and at night its NA - Europe. So based on observation, experience and checking out NL airports on FA, this pattern is consistant.

link to “Great Circle Mapper”, KJFK to EDDF

gc.kls2.com/cgi-bin/gc?PATH=kjfk … MAP-STYLE=


#10

I don’t think private jets are ETOPS certified. As such, they must always be within 60 minutes of a diversion field, which would keep them off some of the NATs and instead fly closer to land.


#11

This is incorrect.
ETOPS rules are only for twin engine commercial air transports.
Twin engine jets fly across the pond every day. Same goes for Hawaii.


#12

James is correct.
ETOPS does not apply to private aircraft, although there are some goings on at FAA along those lines. However, There is no requirement for them to be within 60 minutes, or any other time limit, of a divert airport.
Hopefully one of the guys who has spent more time than I have out over the big big big blue ocean can weigh in on that.


#13

I know a guy who flies his PC12 to Bermuda, 750+ miles over water from the Boston area.
There’s nothing in part 91 regarding distance from land rules, multi or single.


#14

don’t forget about the availability of wake, kwajalein and other small islands in the pacific with regard to taking more “southern” routes across the pacific. Thats how even commercial planes can fly LAX/SFO-GUM, HNL-GUM, I’ve even seen LAX-RPLL(manila)/WSSS(Singapore)


#15

We fly our Lear 36’s from most west coast airports to Hawaii all the time. Only once have we had some unexpected winds which puckered us up for awhile. Occasionally, winds prevent us from doing the route, so we fly up to Kodiak or Adak, then fly south to Hawaii. Makes for a LONG day.

–spud–:slight_smile:


#16

Sorry, Allen, I wasn’t trying to make that inference. Perhaps I should have said “perceived” level of safety. I think many pilots of smaller aircraft would feel less comfortable without the hefty back-up systems of the big jets and big fuel tanks and, thus, would prefer a routing more conformable with a coastline even if it does cost more to fly that routing.