View Full Version : Low cruise altitude?
Mark in CA
3rd Jun 2018, 09:10
Was just tracking my friend's flight today from SVO to LAX on Aeroflot (SU 106), and notice the flight plan that was filed has the cruising altitude of only 29,000 ft. Does that seem a bit low for such a flight. I've flown a lot of flights between Europe and the US West Coast, and seem to recall they all flew at between 36,000 and 42,000 feet. Is there some advantage to the lower altitude? Equipment on this SU 106 flight is 777-300ER.
Katamarino
3rd Jun 2018, 12:46
Filed altitude is typically just the initial altitude; it might be because the aircraft is very heavy. Usually they'll climb higher through the flight as fuel is burned off.
Quartz-1
3rd Jun 2018, 14:08
Perhaps it was that low to catch the jet stream?
Mark in CA
3rd Jun 2018, 14:37
Perhaps it was that low to catch the jet stream?
Wrong direction.
Max altitude, so far, just over half-way there, is 32,000 feet.
Not sure of the rules anymore, (seem 20 years ago since I was last there) but some routes/airspace need crew & a/c certification. That airspace block used to start above FL290. Thus is the a/c or crew was not certified to enter the vertical block of airspace it had to fly under or over. Or did you say that it subsequently climbed to FL320? That could be a weight issue or it was no longer restricted by airspace. I'm not familiar with the route.
FWIW in the general scheme of things F290 as an initial cruising level is definitely unusually low for a 777-300ER operating without any en-route aircraft performance restrictions. Even on an ultra longhaul setvice up near MTOW on a warmish day you’d expect to be intially cruising in the low 30’s.
Maybe there are indeed environmental or airspace issues in play.
Pom Pax
3rd Jun 2018, 16:23
Quartz-1 (https://www.pprune.org/members/267512-quartz-1) Perhaps it was that low to catch the jet stream?.
Wrong direction.
Max altitude, so far, just over half-way there, is 32,000 feet.
Logical follow up to those two remarks To avoid jet stream.
atr-drivr
3rd Jun 2018, 16:25
We went down to 280 from JFK to SFO yesterday due to continuous light to continuous moderate turbulence most of the way....that would be a possibility...
Mark in CA
7th Jun 2018, 04:49
Just a quick follow-up. That flight eventually climbed to something like 36,000 feet. I also noticed its track started off from SVO, rather than following a "normal" great circle route, much more northerly. I do not think it was weather related. It had the effect that the plane stayed in Russian airspace until over water rather than flying over Finland/Sweden/Norway on its way to Greenland. This must have added some extra distance to the route.
Hokulea
13th Jun 2018, 10:32
Many years ago I used to fly regularly between Chicago and Honolulu on American's now obselete DC-10s, and the altitude they flew was regularly 29,000 feet - it was to avoid headwinds in the jet stream. Just two months ago I flew from LA to Honolulu at 30,000 feet for the same reason. That was an A321. Yesterday's flight was 32,000 feet.