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Assume that a Boeing 747 or Airbus A380 takes off at max takeoff weight. Minutes after takeoff, 3 engines fail, leaving only 1 engine operating.

Can the aircraft achieve a positive rate of climb in this situation?

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    $\begingroup$ For a very short period of time using momentum and existing airspeed, but I don't think either aircraft can climb on a single engine. Hopefully Terry can chime in on this one. $\endgroup$ – Ron Beyer Oct 13 '16 at 14:14
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    $\begingroup$ At max weight I doubt even 2 engines could produce a positive rate of climb. $\endgroup$ – Mike Sowsun Oct 13 '16 at 14:22
  • $\begingroup$ In a takeoff configuration at or near MTOW, no; it would probably require at least two engine operative in these conditions plus low altitudes and air at or near STP. After a few hours of fuel burn in a cruise configuration, most likely yes. Lighter weights plus cleaned up would allow for a positive rate on one engine. $\endgroup$ – Carlo Felicione Oct 13 '16 at 14:33
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    $\begingroup$ @RonBeyer I think you're correct, although I have no documentation on that condition. My guess is that for the 747, the problem would be dumping fuel fast enough to stay in the air. $\endgroup$ – Terry Oct 13 '16 at 14:34
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    $\begingroup$ Related: Can the Airbus A380 safely fly with two engines out on the same wing? $\endgroup$ – ymb1 Oct 13 '16 at 15:17
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I doubt that either aircraft can climb on a single engine (though momentum and airspeed could help, as @RonBeyer already commented). The closest an aircraft came to this condition was the British Airways Flight 9 when it ingested volcanic Ash.

During this incident, the aircraft flew on one engine for around 90 seconds. In this case, a report from the flying magazine says:

On one engine they could maintain height at 13,000 ft; over the next five minutes, the next three engines relit, and they begun a climb.

This seems to indicate that the aircraft was not able to climb with one engine. However, during this incident, the aircraft was not climbing, but was descending at 1800m per minute.

Note: There seems to be some confusion about the altitude. The captain's website gives the altitude as 12,000 ft.

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    $\begingroup$ Actually, it was this incident which inspired my question. $\endgroup$ – kevin Oct 13 '16 at 17:10

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