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Under the Volcano

Under the Volcano

In June 1982, British Airways Flight 9, a Boeing 747-236B en route from Kuala Lumpur to Perth, flew into a cloud of volcanic ash caused by the eruption of an Indonesian volcano, resulting in the failure of all four engines. The aircraft was diverted to Jakarta and thankfully, was able to glide far enough to exit the ash cloud, enabling the aircraft to land safely on three engines. John McHarg tells the remarkable story.

 

QX LHRWWBA KULKOBA PERKQBA PERKOQF

HLMKKGA 241342NN

MVT BA9.23 GBDXH KULPER

DIV HLM ENGINES FAILURE

EA TBA NI TBA

This was the telex that was dropped on my desk about 60 minutes before I finished a 1500-2300 shift as Duty Airport Manager at Perth’s International Airport, on the night of Friday 25th June 1982.

It told me that BA9, registration G-BDXH, en route Kuala Lumpur – Perth was diverting to Jakarta with “engines (sic) failure”. Jakarta hadn’t worked out an ETA yet, nor had they decided when they’d next update the situation (NI- Next Info). This incident was to be one that took me closest to involvement in the unthinkable – an air disaster, although I wasn’t to realise until the next day, just how close.

In those pre Landerisation days, sadly the “World’s Favourite Airline” wasn’t the “World’s Most Punctual Airline”, and it was something of an industry joke that BA didn’t file schedules twice annually; they found it more practical to simply file a calendar.

This day was no exception.

The flight should have arrived at the end of my shift, with the incoming DAM to supervise the departure. As it was, I attached the signal to the handover and highlighted the further delay for my relief’s action. It wasn’t until the following morning that the full story and a sense of my good fortune and that of 247 passengers would dawn on me.

Even now, with lessons learnt the hard way through this and other incidents involving volcanic ash (SQ23 Singapore-Perth flew through the fringes of the cloud the same evening and again three weeks later), it’s hard to understand that a major volcano could erupt 100 miles SSE of Jakarta, and the authorities not NOTAM the event, nor issue a SIGMET.

Later, looking at the satellite pictures for BA9’s track, there was a teardrop shaped cloudlike formation to the SW of Mt Galunggung. I suppose everyone had assumed it was a large cloud composed of water vapour as normal that would be picked up by the aircraft’s weather radar, which registers and reports concentrations of water vapour in the atmosphere.

Wrong.

It was ash and airborne pumice, as dry as a dead dingo’s donger and invisible to radar and normal vision at night.

The particles were also electrically charged which would show as St Elmo’s Fire around the cockpit windows, and also cause the ash and grit to bond to hot metallic surfaces in the Rolls Royce RB211 engines.

First indications of a developing problem occurred while Captain Eric Moody was off the flight deck in the lavatory. F/O Roger Greaves was in temporary command in the right hand chair, the FEO, Barry Townley-Freeman was seated at his panel, behind Roger, and the Captain’s chair was vacant . Over the next 45 minutes or so, these three men, and the Cabin Crew, would display courage and airmanship of the highest order, and would re-coup for BA every penny spent on their training.

Moody was puzzled on his return to the Flight Deck. He’d had to use one of the main deck toilets, and was on his way back to the cockpit, and talking to the Purser (No. 2 in the Cabin for BA after the CSD). As he ascended the spiral stairs to the upper deck and the floor was at eye level he noticed what seemed to be smoke coming from the air conditioning vents and got a “whiff” of what he thought might be an electrical fire. At the time he associated the smell with that produced by the London tube trains’ brake pads, and expected to walk back onto his flight deck to the news the crew had spotted an electrical fire.

Most pilots with significant hours invested in their profession have seen the eerie, dancing “flames” of St Elmo’s Fire.

Sailors too, and they claim St Elmo as their Patron Saint. He is also the Patron Saint of Abdominal Pain. Feel at liberty to share this information with friends. The flames themselves are synthetic and are caused by discharges of plasma (ionised gas) in a strong electrical field. Local surface voltages of around 1000V are needed to initiate the discharges which are more prone to appear around pointed surfaces like lightning rods.

In the right conditions they are capable of initiating a fire or explosion. Interestingly, observers watching the Hindenberg hydrogen filled airship dock in a thunderstorm at Lakehurst NAS near New York in 1937, reported seeing St Elmo’s discharges running along the airship’s upper “keel” just before she burst into flame.

St Elmo himself had a gift for upsetting important people, specifically Roman Emperors and his end was very untidy indeed, involving ropes and four strong horses, all encouraged to pull in different directions. Eric, Roger and Barry had all seen these eerie dancing discharges before, but never so intense, nor ever in the dry, cold air at FL370.

They selected the seat belt sign on.

The phenomena persisted and soon an ominous sulphurous smell began to pervade the cabin. A glance aft, out of the cockpit windows showed another unsettling phenomena, again courtesy of St Elmo. There seemed to be a powerful light source inside each of G-BDXH’s RB211 engines, shining forward and “strobing” in sync with some unknown internal source. One of the two pilots reached up to the overhead panel, and switched on the aeroplane’s landing lights in the hope it might bring some answers, but no luck. It simply looked like BA9 was flying through high cloud.

At this point it’s likely that the lenses on each of the aircraft’s landing lights were being seriously abraded by the grit she was flying through, and each light’s output was seriously degraded. They’d realise how seriously on approach to Halim (Jakarta) and afterwards on the ground, when they completed a collective “walkaround”.

At 2044 Perth time, Number 4 engine lost interest in further toil and “spooled” down. Barry Townley-Freeman picked up this unsettling news from his engine gauges before either of the pilots noticed the increasing asymmetry caused by the loss of an outboard engine. The crew shut down the engine, discontinued its flow of fuel and armed the fire suppression system. Within 30 seconds, engine Number 2 showed indications of an un-commanded power roll-back and was shut down, followed immediately by numbers 1 and 3.

The centre pedestal separating the two pilots is now looking pretty untidy, with Number 4 thrust lever back on its stop having been shut down IAW Engine Failure Procedures, and the other three pretty much where they were when the roll backs started and the engines shut themselves down.

Moody then called for the “Loss of all Generators” Checklist which seemed a good place to start. This checklist started with the question “Are all the engines running” and this may have been the first time any crew member could have responded “No”. Initially, this checklist formed the basis for the crew’s attempts to relight the three improperly shut down engines (1, 2 and 3) – Number 4, shut down properly, would have to wait. None of the three engines responded so Eric made the reasonable assumption that all three had been victims of the same malaise that had afflicted the first to fail, Number 4, and the thrust lever on the still dead Number 4 engine was brought back off its stop to align with the other three, and Number 4’s Fire Handle was returned to its unarmed position in the overhead panel.

From this point their restart attempts would involve all four engines, and with hindsight, they’d realise that Number 4 was the first to restart because it was the first to shutdown, had sustained less damage than the other three, and was quickest to cool.

There’s not normally much engine noise on the flight deck, just the noise made by the airflow as it’s shouldered out of the way and while the crew might have noticed a subtle change in the noise of the airflow round the windows and over the 747’s signature “hump” they wouldn’t connect with ash until later when they saw what had become of their cockpit glass, and later still, G-BDXH’s paint work.

Without power the aeroplane began the long glide to the South Java Sea and perhaps the first controlled ditching at sea.

After some quick mental arithmetic, based around the fact they were about 150nms south of the Java Coast and the Safety Height (MSA) was 10,500’, the crew decided they could glide about 90nm’s or for about 30 minutes but not towards Jakarta or Java itself. There was a mountain range between them and Jakarta, so there weren’t too many attractive options available that didn’t involve an unlit landing in a seaway, some distance from the coast with just the sharks for company. It just hadn’t been done before and didn’t get too many column inches in the Flight Manual.

By this time Roger Greaves had transmitted a MAYDAY call.

Jakarta had misunderstood the aircraft’s first transmission about the loss of all four engines, and was working on the premise that only Number 4 was shut down. A nearby Singapore Airlines aircraft intervened and corrected Jakarta’s mistake by radio. Eric believes this 747 in fact turned back to Singapore on the strength of BA9’s experiences. It must have been Sydney-bound as Perth’s SQ23 arrived in the WA capital around its scheduled time.

On the Flight Deck Roger Greaves found his mask was unserviceable, and Eric Moody now had another problem.

Stay high and continue the glide, but risk a loss of consciousness for his F/O, or quickly trade height for oxygen and have two heads and four hands available up front to fly. He chose the latter option.

Eric disconnected the Autopilot at around 26,000’ when Roger found his mask inoperative, and now the “descent” became a “dive” (I had a few problems writing that phrase. One “dives” Cessna 152’s or F18’s, but generally not B747’s) and was hand flying as he levelled off at about 20,000’ just as Roger declared repairs to his mask finished.

Having donned his mask, he asked Eric what his ASI (Air Speed Indicator) was telling him.Eric responded “270 knots”, and Roger then identified the 50 knot discrepancy between Eric’s and his instrument, which was reading 320 knots.

While they were sorting out the ASI problem, G-BDXH continued a more gentle descent to around 18,000’, and at this point Eric got a warning on the Flight Deck, that the passengers’ oxygen masks, “the Rubber jungle” had deployed from the PSU’s above each seat row. He tried to raise the CSD on the interphone which wasn’t working, and realising the only way he could tell his Cabin Crew what was happening, was through a P/A announcement, “piped” through the entire cabin.

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.”

The restart routine continued on Number 4.

At 2158 local time Perth, and 14 minutes after things had got very quiet on board, Number 4 engine’s gauges started to move off their stops, and the engine started to produce the low frequency rumble unique to RB211’s as they spool up, felt in the gut rather than heard. When the engine first went into service this had nearly become an industrial concern for Ground Engineers supervising startups and pushbacks, until they were re-assured that there were no secondary physiological issues involved.

G-BDXH was already pointed in the general direction of Jakarta, but there was no way Moody could coax enough thrust out of one engine to climb and clear the intervening mountains. Ninety seconds after Number 4’s blessed re-start, Number 3 responded and the needles moved off the stops to flight idle thrust and beyond. Then, within 30 seconds, numbers 1 and 2 responded and suddenly BA9 was flying again. Number 2 proved unstable and was shut down to minimise damage and distractions. BA9 was still marginally above MSA (Minimum Safe Altitude) when she started flying again and the crew reported their improved situation to Jakarta Approach.

They were asked to climb to 15000’ so Jakarta’s radar could “see” them over the mountain range. Bad call. They re-entered the ash cloud with its usual visual and olfactory signals, and Moody descended quickly to 12,000’ and once clear of the mountains commenced the three-engined descent into Halim.

Galunggung had one last surprise and challenge up her sleeve.

At the point the crew would have expected to have the lights of Jakarta and Halim “visual” but all they had through their forward facing windows was a smudgy, indistinct glow. They were looking through opaque, frosted glass.

Only an inch or two of glass immediately beside the window frames had been spared. Vision out of the side windows was good, but even with an undercarriage as robust and forgiving as the 747’s, landing sideways is not recommended. Then Jakarta Approach sprung another little surprise.

BA9 could have reasonably expected Halim’s ILS to be online. An ILS (Instrument Landing System) involves the transmission of two radio signals, each perpendicular to the other. One (vertical) defines the extended runway centreline (Localiser) and the other, propagated horizontally, gives the pilot a 3 degree glide slope. By keeping the plane at the intersection of the two beams, the plane’s sliding down an invisible banister in the sky, that will place it over the business end of the runway (the threshold) about 30 feet above the concrete, and allow the pilot to take over and land the aircraft.

Some systems even allow the plane to proceed one step further and land itself. This is called autoland, and initially pilots were pretty sensitive about it as the aircraft was generally able to put itself on the runway without even a ripple in the Moet.

Moody’s problem was that he could keep the plane on the centreline, but he’d have to have Roger Greaves calling the altitude from the altimeter. Greaves could also keep an eye out his window to confirm what the previously unreliable altimeters were telling him.

Moody had to do a succession of quick mental sums to confirm he was “on the money” with his rate of descent – the one in three rule – that approximates the three degree descent he wanted. Ideally, with reliable instruments, this meant descending 300 feet in every mile. His DME (Distance Measuring Equipment) gave him his distance from the runway, and the old 1:3 rule said at 10 nms from the runway (about a mile) the plane should be about 3,000 ft above the ground. At 6 nms he should be 1800’ AGL, 3 nms 900’ AGL and so on. It worked.

Afterwards Moody, ever the master of understatement, would describe the approach as “a bit like negotiating one’s way up a badger’s arse”. The aircraft touched down, and rolled out.

It had to be towed to the Terminal, as the crew simply couldn’t see where they were going. Before the Tech Crew left the cockpit, after the passengers had disembarked, Moody insisted they go through the Flight Library again, to see whether they’d done anything to precipitate the near disaster.

They still didn’t know what had hit them or more correctly what they’d hit, and it wasn’t until all three did a post flight walk-around that the realisation of their near catastrophe dawned on them. The perspex covers on all the landing lights were opaque, sandblasted. Cockpit windows too. All the paint had been stripped from the leading edges of wings, horizontal and vertical stabiliser, radome and cockpit. G-BDXH was a mess.

Rolls Royce would arrange for engines 1, 2, and 3 to be removed and freighted back to the UK where they were stripped and just what pumice and ash can do to exotic hot metals could be seen first-hand. RR believed that as the aircraft had descended out of the cloud with all engines shut down and cooling, enough contamination had broken away from the fan blades and stators to allow the restart.

Engines 1, 2 and 3 would be replaced before G-BDXH could be ferried home. Cockpit glass was replaced and all the fuel tanks drained and flushed to remove ash residues that had found their way in. She was later sold to European Aviation Air Charter who flew her for a while before removing her from service in 2004. She was scrapped in 2009 and the fuselage sold to the environmental group 10:10 who push the global warming barrow. They planned to convert the duralium alloy used in the old girl’s skin into key tags bearing the 10:10 logo.

Yep.

Eric was later presented with the Captain’s yoke off G-BDXH by an old friend in thanks for fulfilling a speaking engagement, and it adorns a wall in his study still. While Eric Moody continued to fly the line for BA, they’d always roster him and other crew members, back through Perth on the anniversary of this crew’s masterful display of airmanship, and Moody and the survivors would convene for the annual Meeting of the Galunggung Gliding Club.

Medals and recognition would come selectively to the Crew.

Eric and the Cabin Services Director would each be awarded The Queen’s Commendation of Valuable Services in the Air but despite his best efforts there’d be no proper acknowledgement of the efforts of Roger Greaves and Barry Townley-Freeman. Roger and Barry are still around and in contact with Eric.

The incident raised awareness of the perils to aviation of ash clouds and formal reporting procedures were introduced by ICAO. Incredibly, three weeks after the airspace around Galunggung re-opened following the BA9 incident, the volcano erupted again, without any notification from the Indonesian authorities, and an SQ23 flight en route Perth from Singapore flew through the cloud, forcing the shutdown of three engines.

The airway that was used as a matter of course from Singapore to Perth was re-aligned to clear any future eruptions.

And that, gentle readers, is about as close as I ever want to be to a catastrophic aircraft accident.

Acknowledgements

This piece couldn’t have been finished in any readable or reliable form, without Eric Moody’s generous and unstinting advice and constructive suggestions. As authors say, the accuracy belongs to Eric, the mistakes to me. Elsewhere some information was supplied by “Air Crash Investigation” in its endless re-runs on Foxtel.

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