British Airways Flight 9 lost all 4 engines while flying through volcanic ash in 1982.

Captain Moody made an announcement that has gone down in aviation history as a masterpiece of understatement: Ladies and Gentlemen, this is your Captain speaking. We have a small problem. All four engines have stopped. We are doing our damnedest to get them going again. I trust you are not in too much distress.

At approximately 13:42 GMT, engine number four surged and then flamed out.

Less than a minute after the first engine failed, engine two surged and flamed out. Before the flight crew could begin the engine failure drills, engines one and three shut down almost simultaneously.

At 13,500ft, the flight crew attempted one last engine restart procedure before turning for the ocean and the risky prospect of a water ditching. Without warning, number four engine sparked into life, and at 13:56 GMT, Captain Moody used its power to reduce the rate of descent. Shortly therafter, engine three restarted, followed shortly by engines one and two.