Gliding a B747 Out of Volcanic Ash

Air Safety Week, June 28, 2004

"Good evening, ladies and gentlemen. This is your captain speaking. We have a small problem. All four engines have stopped. We are all doing our damnedest to get them going again. I trust you are not in too much distress."

That was the public address (PA) announcement made by Capt. Eric Moody to the 247 passengers of British Airways Flight 9, 22 years ago on June 24, 1982. It was made a few moments after losing all four engines on the B747 from a penetration into a cloud of volcanic ash at 37,000 feet. Moody vividly remembers the event, which he recounted at last week's 2d International Conference on Volcanic Ash and Aviation Safety in Washington, D.C.

What Moody did not know at the time was that Mt. Galunggung had erupted two hours before Flight 9's nighttime takeoff for the five-hour flight from Kuala Lumpur, Malaysia, to Perth, Australia. The volcano, located some 110 miles southeast of Jakarta, erupted some two hours before departure, for the ninth time that year, spewing an enormous cloud of ash and gas high into the atmosphere, and into the path of Flight 9.

The geologic facts would be pieced together after the flight. At the moment of his brief address to the passengers, Moody did not know the precise nature of the emergency he was facing. First Officer Roger Greaves and Flight Engineer Barry Townley-Freeman were equally perplexed.

The crisis began innocuously enough. The weather radar showed the way ahead was clear. On autopilot, the airplane was cruising serenely along airway B69, south of Jakarta. Moody excused himself from the cockpit to use the lavatory. Finding the upper deck toilet occupied, he descended to the main deck. During a brief chat with the purser, he was called to the flight deck. As he ascended the stairs, Moody recalled seeing smoke coming from the floor vents and noticing an "electrical burning smell."

When he got to the cockpit, he immediately noticed a bright orange, red and blue display of St. Elmo's Fire playing across the windscreens. Strapping himself into his seat, Moody noticed the display intensifying, momentarily distracting him from determining the source of smoke billowing out of the air conditioning vents. Sparks were flying off the nose and windscreen (these were caused by the impact of tiny particles, much the way helicopter blades rotating in ground effect above desert sand will look like fiery disks caused by the strikes of thousands of grains on the leading edges). The engines were glowing brightly from within, looking to Moody like a "magnesium fire."

As the fireworks intensified, engine #4 starting winding down. The engine fire drill was initiated. The fuel to engine #4 was cut off, the throttle was pulled back. They stopped short of discharging Halon fire-extinguishing agent into the engine, as there was no fire indicated.

About 30 seconds later engine #2 failed. In a few more seconds, #3 was gone, followed by engine #1. Flight Engineer Townley-Freeman remarked on the obvious, "Sorry, we've lost the lot."

Moody recalled, "Even though we'd trained for it at British Airways, and practiced it in the simulator, we didn't believe what was happening."

With the autopilot still engaged, the nose began to rise as speed decreased (ASW note: with all four engines flamed out, the autopilot would be trimming to fly level as the speed decreased. Ultimately, stalling with full nose-up elevator trim is akin to what happens to turboprops in their undetected icing encounters and speed losses).

"We turned to the left to avoid any oncoming aircraft on a reciprocal route and were heading to Java over the Indian Ocean," Moody said.

He ordered First Officer Greaves to put out a Mayday to air traffic control (ATC) at Jakarta. The airport was some 40 minutes flying time away.

"Jakarta, Mayday Speedbird 9. We've lost all four engines. We're leaving 370," Greaves radioed.

He was transmitting through a tremendous amount of static. Fortunately, the message was repeated by a Singapore Airlines jet following Flight 9 by some 20 miles. Unfortunately, the message received by ATC was only that #4 engine had failed, not ALL four.

"We could see the fans were rotating, that they weren't locked up, so we put on both banks of igniters and anti-ice," Moody recalled (the windmilling fans showed a rotation of about 30 percent on the N1 gauges). The fuel, though, was not igniting inside the engines, producing thrust, but rather was igniting behind them, treating passengers to a spectacular display of flames.

"I couldn't see any cause, and remarked to the crew, 'We've cocked something up,' " Moody said. Turning to look at the flight engineer's panel, Moody saw indications of a complete electrical failure.

Perhaps the engines failed from fuel mismanagement, the underlying reason for the all-engines-out drill for recurrent training. Pumps and cross feed valves were checked. Circuit breakers were checked. Engine anti-icing was checked.

Nothing seemed amiss. Even though the Rolls Royce engines were most likely to restart in conditions below 29,000 feet and in a speed range of 250-270 knots, according to the engine manufacturer's guidance, Moody and crew attempted to restart engines #1, #2 and #3 immediately as they began to descend from 37,000 feet. This activity, Moody said, "Was per our training, but we did not expect them to light up and, after a couple tries, they didn't."