Targowski From United States of America, joined Aug 2003, 127 posts, RR: 0 Posted (8 years 10 months 4 weeks 1 day 23 hours ago) and read 4550 times:
i've heard that due to the altitude and position of the himilayas, twins have more difficulty or have to reroute around the himilayas to meet ETOPS. i'm wondering if (1) this is true and (2) how this affects AA's ORD-DEL and CO's EWR-DEL since both use 777s. I know the short lived AC YYZ-DEL used A340s.
SunriseValley From Canada, joined Jul 2004, 5493 posts, RR: 5
Reply 1, posted (8 years 10 months 4 weeks 1 day 21 hours ago) and read 4406 times:
Do a search of the archives for a Pakistan Airlines thread that literally flogged this particular issue to death.
Not sure why you would think it is ETOPS related in so far as proximity to the Himalaya's are concerned. ETOPS is primarily an over water issue.
COEWR787 From United States of America, joined Mar 2005, 357 posts, RR: 3
Reply 5, posted (8 years 10 months 4 weeks 1 day 20 hours ago) and read 4223 times:
Quoting Blrsea (Reply 4): There were lots of threads on this. The flight path doesnt go over the himalayas. It goes over central asia ->Afghanistan-> pakistan ->India. It doesn't have to go over himalayas
Correct. The flight path usually crosses the Hindu Kush over Afghanistan, and that has never been a problem for any plane.
As for Himalayas, there are restrictions on flying across Tibet in general, irrespective of how many engines you have, because in case of cabin depressurization it is impossible to bring the plane down to 7000' without going a few thousand feet underground . The plateau is about 11 to 12 thousand feet average altitude. This is obeyed quite carefully. For example, last time I flew SQ from EWR to SIN we flew an almost straight route across the pole, except for a divergence to the left to avoid a corner of the Tibetan plateau.
BTW, flight that originate or terminate in Tibet of course fly over Tibet. As a matter of fact when I flew from Lhasa to Kathmandu the aircraft was a twin (757) which flew right over Mount Everest. Can't get any higher than that, and yet it was a twin.