Sunday, December 21, 2014

Capt. G A Fernando: And they called it pilot error

by Capt. G A Fernando
A former member of the Accident Investigation Team of The Civil Aviation Authority Sri Lanka

On the morning of November 28, 1979 an Air New Zealand McDonnell Douglas DC-10-30 left Auckland for the Antarctica and the South Pole on a sightseeing flight. In command was Capt. Jim Collins, an experienced pilot with 11,000 hours of flying experience of which almost 3,000 were on the DC-10. This was the 14th such flight undertaken by Air New Zealand, and because it would be longer than usual (11 hours) Capt. Collins had two First Officers (co-pilots) and two Flight Engineers to provide in-flight relief.

Collins was both surprised and delighted when his roster showed that he was slated to operate Flight TE901 because it was a rare privilege. Air New Zealand operated four such flights a year during summer when there was 24/7 sunshine in the Antarctic.

The crew reported for a special briefing on the Antarctica flight as early as November 9, and were told that their proposed route would take them from Auckland to Invercargill and thence over the Auckland Islands at the southernmost part of New Zealand, onward to Cape Hallett and then the McMurdo Sound, a forty mile-wide, obstacle-free, frozen sea where there was an American Base (Operation Deep Freeze). Finally, they would return to Auckland via Christchurch. An old Computerized Flight Plan (CFP) of a similar flight conducted by Air New Zealand on November 6 was given for reference as their routing will be the same.

Forty miles, in Sri Lankan terms as the crow flies, is about the distance from Ratmalana Airport to Adam's Peak. At the briefing the crew was also told that if the weather was clear they could do a low pass at 1,500ft over the New Zealand (Scott) Base and US Base with the permission of McMurdo Radar before returning to Christchurch. Capt. Collins had taken his atlas and note book along, and at the briefing had plotted the geographical coordinates. The crew was told that significant high ground such as Mt. Erebus (13,000ft), an active volcano, would be to the left of track. It was a pre-planned route with geographical coordinates of latitude and longitude which could be fed into the Inertial Navigation Computers that could be coupled to the Autopilot for navigation purposes.

At his home on the night before the flight Capt. Collins had drawn the intended track on a map and his atlas using the old CFP. Usually the crew would have been given a magnetic cassette tape with the pre-planned route loaded on it, but because this was an unscheduled flight, the pilots would have to load the geographical coordinates from their CFP, manually into the inertial computers through a Cockpit Display Unit (CDU). Inertial navigation does not rely on any external aids to navigation and is totally self-contained. This navigation system, which was invented for use in guided missiles, works on the measurement of acceleration in the North/South and East/West directions, and updates an entered position. It therefore could navigate from one entered position (called a Waypoint) to another. In fact the whole route could be programmed before departure. It was very accurate and the pilots of modern big jets trusted the system implicitly as it consists of three different computers monitoring each other. So if one gave erroneous readings that would be detected and eliminated.

The flight was uneventful until its final impact with terrain on the planned descent into McMurdo Sound. The point of impact was 26 miles left of the intended track with the summit of Mt. Erebus slightly to the right instead of the left. All 257 passengers and crew were lost, putting the country of three million people into an acute state of shock. How could this happen? Air New Zealand was a well-respected airline with a good track record. Their company slogan was 'Nobody does it Better'.

The Chief Accident Investigator of New Zealand's Civil Aviation Department, Ron Chippindale, and his team got on to the job immediately and conducted a thorough investigation. The so-called 'black boxes' (Cockpit Voice Recorder and Flight Data Recorder) - which are in fact painted a bright shade of fluoro-orange for easy location at a crash site - were recovered and their data downloaded and decoded. As this had been a sightseeing or pleasure flight, almost every passenger carried a camera. Therefore, many photos were also available for analysis. Unfortunately, the DC-10 aircraft type had had two previous serious crashes in the recent past (in Paris and Chicago), so mechanical failure could not be ruled out.

Subsequently, however, it was discovered that the aircraft was fully operational and technically sound, and that unlike the other two recent crashes where the airplanes were out of control when they hit the ground, in this case the aircraft was under the full control of the Captain and his crew, and almost at level flight when it impacted the terrain.

One of the items recovered from the crash site was the note book of Capt. Collins, and that was returned to the family. In March 1980, when the entire family was out of their home for the first time after the crash, a person or persons unknown broke into the house, possibly to get access to the dead Captain's note book. What they were looking for, and who the intruders were, remains a mystery to this day.

The Civil Aviation Department Chief Inspector's report was finally released in June 1980. In essence it stated that the airplane was flying in cloud and the crew was unsure of their position and descended too low and hit the northern flanks of Mt. Erebus under full control and that it pointed to 'Pilot Error'. This was accepted willingly by Air New Zealand. To all intents and purposes it seemed like a complete 'whitewash' as dead men cannot defend themselves. The 'Human Factors' and the cause behind cause had been glossed over.

By July the same year the Attorney General of New Zealand ordered a Royal Commission of Inquiry into the accident due to the growing public uneasiness and rising anger felt by the airline pilots, flight engineers and next of kin of the 20 crewmembers. A well-respected judge named P. T. Mahon was to head it.

One of the greatest critics of the Civil Aviation Department Chief Inspector's report was Capt. Gordon Vette, a senior Air New Zealand pilot and instructor who knew Capt. Jim Collins, the Captain of TE109. Only a year earlier Gordon Vette became famous for helping to rescue the pilot of a single-engine Cessna 188 lost over the Pacific Ocean, and was recognised by the Guild of Air Pilots and Navigators of the United Kingdom (GAPAN). In 1993 the story was made into a film titled 'Mercy Mission'. By standing up for his friend, Vette's loyalty to the airline was questioned by many of his friends and associates who knew that by doing so he was exposing Air New Zealand to litigation, if found guilty of negligence.

During the hearings, in their evidence both executive and line pilots of Air New Zealand had been unanimous in stating that Capt. Jim Collins was known to be careful, conscientious and methodical. Capt. Vette provided technical support to Justice Mahon. After 75 days of hearings, it was discovered that, unknown to the crew, the McMurdo waypoint had been changed in the Computerised Flight Plan (CFP) the night before the doomed flight. The new track now defined would take the aircraft right over Mt. Erebus and not along the forty mile-wide McMurdo Sound.

This amended position in the current CFP of their flight, was what was entered into the 'box' on the flightdeck by the crew, and the INS system faithfully gave guidance to the Auto flight system to fly the aircraft toward the mountain. It was also proved that the Chief Investigator got it wrong. TE901 was not inside cloud but flying in clear weather.

If that was so, why did the crew not see the high ground? It was proved by Capt. Vette that the crew experienced a condition called 'sector whiteout'. If there was a strati-form layer of cloud above, objects such as mountains become invisible on account of the absence of shadows due to reflected light from the snow. An optical illusion tricks the brain which is expecting the aircraft to fly over flat frozen sea which is forty miles wide, as briefed, and deemed to be safe to descend in. Capt. Vette was also able to prove that when flying in the clear, the terrain the ill-fated crew saw was at the same visual angle as the terrain they were expecting to see. Therefore Capt. Collins and his crew had got lured into a visual trap. This led the crew to assume they were on course as briefed. They had no reason to doubt the navigational performance of the aircraft as it was extremely accurate up to Cape Hallett.

The DC-10-30 was a second generation tri-jet which was a 'pilot's dream'. It had, amongst other equipment, weather radar which could be used to 'paint', or scan and reveal, high ground. It was however shown by the manufacturer that mountains covered with powdered snow gave insufficient radar returns. Then what about the Ground Proximity Warning System (GPWS)? It had been introduced not long before and gave out many spurious warnings, If and when it was triggered off, the crew was caught by surprise, and pilots of that vintage didn't trust it totally. Even on that flight Collins did not use full thrust and attempt to climb at the highest angle possible. Had he done so, the outcome may have been different.

By contrast, the computerized, fly-by-wire aircraft of today can provide the maximum performance if the pilot reacts quickly and 'firewalls' (forward to the stop) the thrust levers (throttles) while pulling the control stick back to the stop as the engines will produce the maximum possible power. Meanwhile, the computers automatically monitor the engine conditions and speed will be converted to height in the quickest and most efficient way without the airplane stalling aerodynamically and falling out of the sky. These 'escape procedures' have to be practiced by airline crews every six months to remain current.

This was a landmark case as many reforms were carried out to highlight the organizational responsibility in the ICAO 'Human Factor' writings. This Royal Commission Report in general and Capt. Vette in particular also helped to accelerate the development of the forward-looking, Enhanced Ground Proximity Warning System (EGPWS) which gave color-coded lateral terrain guidance and information to pilots to avoid high ground.

Although the Royal Commission of Inquiry report was presented to the New Zealand Parliament, Ron Chippindale's Civil Aviation Department report was still accepted as the official version of what happened to TE901. Accordingly, it was also rejected by Air New Zealand as there was much at stake for the airline's reputation. It seemed a big mistake to take on the Government and government-owned Air New Zealand. Both Justice Peter Mahon and Capt. Gordon Vette felt the 'heat'. The Judge died at the relatively young age of 62, while Vette was forced to quit for standing up for truth and justice!

However, the New Zealand Air Line Pilots' Association recognized Capt. Vette and he became the first recipient of the Jim Collins Memorial Award for Air Safety. Sadly, by then he had suffered a stroke and was confined to a wheelchair, unable to speak.

Post Script: Twenty years after that fateful crash, Air New Zealand officially apologized to the Collins family for not being there when they needed them most.


No comments:

Post a Comment