Expert: D. Norkus - 8/10/2006

Question
I was just in a Boeing 747 a week ago and I'm very amazed by its physical characteristics. What really got my attention are the four powerful engines that propel the aircraft. I was just wondering if the plane could takeoff, fly, or land with one engine. Is it possible?

Answer
Kevin

To be certified to fly, all airliners must demonstrate a takeoff at max weight with ONE engine inoperative upon rotation. Just one engine on a 747 produces more thrust than all four engines on an early model Boeing 707 combined but the 747 is also a much heavier aircraft their first jet. Not having flown the 747, this is about all I can say from a pilots perspective:

Takeoff- Depending on the actual weight of the aircraft, it may very well be able to takeoff with two engines out (even though that is beyond certification standards) but three would be very iffy if not impossible. (As in the aircraft encountered a flock of birds on take off and lost 3 engines. Especially depending on the engine position and it's affect on yaw.)

Level flight- Weight being a factor again, the aircraft can certainly fly on only one engine. However, maintaining altutude is another matter. On June 24, 1982 a British Airways 747 encountered volcanic ash and lost all 4 of their engines at 37,000ft! Thankfully, the crew managed to eventually get all but one engine going again at about 15,000ft and they landed on three engines. Read about the "Jakarta Incident" and BA 009 here- http://www.findarticles.com/p/articles/mi_m0UBT/is_26_18/ai_n6280435

Landing- It is certainly possible to land on one engine or even with a complete power loss. (As Air Transat recently demonstrated in the Azores.) In the situation of the latter, one had better have some very good power management and spot landing skills though! Airliners must also be able to stop on braking power alone, so the reverse thrust of the engines is just a bonus.


Links of interest-
http://en.wikipedia.org/wiki/Boeing_747
http://www.boeing.com/commercial/747family/pf/pf_facts.html

Hope this helps.

Dottie