Aletho News

Of volcanoes and panic

RIA Novosti military commentator Ilya Kramnik | April 20, 2010

“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 under control. I trust you are not in too much distress.”

This optimistic statement was made on June 24, 1982 aboard a British Airways B-747 airliner bound from London for Auckland with stop-overs in Bombay, Madras, Kuala Lumpur, Perth and Melbourne.

The airliner, however, failed to reach its destination. At 8:40 p.m. Jakarta time, south of Java in the Indian Ocean, co-pilot Roger Greaves and flight engineer Barry Townley-Freeman noticed St. Elmo’s fire appearing on the windshield. St. Elmo’s fire is a special kind of coronal discharge originating from a high-voltage electrical field in the atmosphere. From inside it looked as though tracer bullets were hitting the plane. Soon the aircraft commander, Eric Moody, also noted the phenomenon. He had returned to the cockpit after a short absence.

As a rule, St. Elmo’s fire indicates thunderstorm clouds nearby, but the weather radar displayed nothing of the sort. Still, the crew switched on a de-icing system for safety’s sake and “fasten your belts” lights went on in the cabin.

There was no thunderstorm in the region, however. It appeared that the airliner, flying at an altitude of 11,000 meters, entered a cloud of volcanic ash suddenly spewed by the Javan volcano Galunggung.

Fumes began building in the passenger cabin. Knowing nothing of the volcano, the general conclusion was that it was cigarette smoking – in those days smoking was allowed on aircraft. Soon, however, the fumes thickened, setting off an alarm in the cabin. Crew members set about searching for the cause, but naturally failed to find any.

Meanwhile, many passengers looking out the aircraft windows spotted an unusually brilliant glow on the body surface and particularly on the engines as though each carried a lamp illuminating the way ahead through compressor blades, which created a stroboscopic effect. This glow came from electrified dust particles that had settled on the surface of engine nacelles and on the compressor blades.

At about 8:42 p.m. Jakarta time, engine No. 4 failed because of a flameout. The co-pilot and flight engineer went into the immediate procedure of shutting the engine down, cutting the fuel supply and, just in case, activating a fire-extinguishing system. In the meantime the commander handled the controls, trying to cope with uneven thrust.

The passengers also noticed long yellow glowing streaks emanating from the remaining engines. Less than a minute after shutting down engine No.4, there was a blowout in engine No.2, which also stopped.

Before the crew could initiate the process of cutting down the engine, there was a blowout in the remaining engines, No.1 and No.3, and the windshield went opaque. The flight engineer exclaimed: “I can’t believe it – all the engines have stopped.” It was at that moment that Eric Moody made the statement quoted at the beginning of the article – with a characteristically British sense of humor.

The heavy airliner headed back to Jakarta, hoping to make an emergency landing. But to reach the capital of Indonesia, it was necessary to re-start at least one engine. The alternative was ditching in the far from welcoming waters of the ocean filled with all kinds of dangers – high waves could make the rescue of the crew and passengers difficult, and strong currents could scatter the safety rafts far adrift, not to mention sharks.

An aircraft with a take-off weight of 380 tons became a glider. With the engines shut down, a Jumbo Jet (the nickname of the B-747) can glide 15 km per each kilometer in lost altitude. Commander Moody calculated that from an altitude of 11 km the airliner could glide for 23 minutes, covering a distance of 169 kilometers.

But the descent was more rapid. Air pressure in the cabin dropped: the cabin pressure compressors were driven by the engines which had stopped. Given these bleak realities, the plane was unlikely to negotiate the mountains and land in Jakarta. The crew began preparing to splashdown in the ocean.

The aircraft exited from an ash cloud at 8:56 p.m. Jakarta time, after about 13 minutes of gliding. At that point, it was at 12,000 feet in the air. At this height, the crew managed to fire one engine and then the three others (one engine, however, later went dead again when the Boeing climbed and reentered the cloud). The aircraft was able to successfully land in Jakarta.

The mechanics who broke down the engines found a great mass of molten ash in the turbines that had plugged the lines. All four engines had to be replaced.

Another volcanic incident also involved a Boeing-747, this time flown by KLM on the Amsterdam-Tokyo route. While on approach to Anchorage, Alaska, the airliner hit a cloud of ash spewed by the volcano Mt Redoubt. All four engines failed. But the aircraft captain, Karl van der Elst, managed to save the day – after descending more than 4,000 meters the crew succeeded in restarting the engines.

Both cases show the dangers of volcano eruptions for aircraft but in both cases the aircraft suddenly found themselves in dense ash clouds while in direct proximity to fire-spewing mountains where the concentration of hard particles was the highest.

At a considerable distance from a volcano, the ash concentration in the air falls off by many orders of magnitude, and such a large-scale closing of air space in Eurasia, following the eruption of the Icelandic volcano Eyjafjallojokull, is more reminiscent of hysteria than a real assessment of danger.

Seen against this background, the quiet operation of Russia’s Aeroflot, which continues its flights despite any volcanoes, is worth noting.

See also:

Volcanic ash cloud: Met Office blamed for unnecessary six-day closure

April 20, 2010 - Posted by aletho | Science and Pseudo-Science