RESULTS OF PAST EVENTS INVOLVING VOLCANIC ASH
Significant ash encounters from the past include those involving
such well-known volcanoes as Mt. Pinatubo, Mt. Redoubt, and Mt.
St. Helens. The airplanes that encountered volcanic ash during these
events and in the other events listed chronologically experienced
varying degrees of damage.
St. Helens, United States, 1980.
A 727 and a DC-8 encountered separate ash clouds during this major
eruption. Both airplanes experienced damage to their windshields
and to several systems, but both landed safely despite the windshield
Several 747s encountered ash from this eruption. One airplane lost
thrust from all four engines and descended from 36,000 ft to 12,500
ft before all four engines were restarted. The airplane, on a flight
from Kuala Lumpur, Malaysia, to Perth, Australia, diverted to Jakarta
and landed safely despite major engine damage. This airplane subsequently
had all four engines replaced before returning to service. A few
days after the initial encounters, another 747 flew into the ash
cloud and suffered significant engine damage. This airplane also
diverted to Jakarta and subsequently performed a successful two-engine