Errors of Our Ways: The crash of Ansett New Zealand flight 703

On the 9th of June 1995, a commuter flight in New Zealand disappeared on approach to the city of Palmerston North, sending emergency services racing to determine the fate of 21 passengers and crew. But before they could find the site, they received a welcome surprise: one of the passengers, having survived the crash, used his cell phone to call for help, leading to the discovery of a mangled plane atop a fog-shrouded mountain, where 17 people, including the pilots, were waiting for rescue. Four others lay dead or mortally wounded, killed in the impact and the fire which followed.

With so many living witnesses, two working flight recorders, and a mostly intact airplane, investigators were confident that the cause of the crash could be fully elucidated. Instead, the inquiry became mired in controversy. The plane had suffered a landing gear failure, forcing the pilots to use an alternate extension procedure, but as they tried to work through the problem, the aircraft descended straight into a mountain — a scenario which could have been avoided if a critical warning, conspicuously missing from the cockpit recording, had sounded. All that was clear enough, but the details would nevertheless become the subject of debate for years to come as prosecutors sought to answer a less safety-oriented question: did the captain, in letting his plane drop too low, commit a crime?

◊◊◊

Throughout much of the mid-to-late 20th century, Australia’s domestic flight network was a government-sponsored duopoly dominated by two airlines: Trans Australia Airlines, and Ansett Australia, a legacy carrier founded by Reginald Ansett in 1935. From 1979, the airline, commonly referred to simply as “Ansett,” was owned and controlled by Rupert Murdoch’s News Corporation, publisher of Fox News, The Sun, The Times, The New York Post, and other well-known tabloids — an unusual ownership structure to be sure, but not one which prevented it from successfully carrying millions of passengers through both its main division and its subsidiary Ansett New Zealand, which was launched in 1987.

Ansett New Zealand conducted domestic flights within New Zealand using a mixed jet and turboprop fleet consisting mainly of Boeing 737s, British Aerospace 146 quad-jets, and de Havilland Canada DHC-8–100 twin turboprops, more popularly known as “Dash 8s.” The high-wing, 37-passenger Dash 8s, designed for short-field takeoffs and landings, were ideal for hopping between smaller cities in New Zealand’s interior.

Among these destinations was the city of Palmerston North (Te Papaioea), known to locals as Palmy, which today is home to some 90,000 people and is the eighth largest city in New Zealand. Ansett New Zealand operated a regular flight within the North Island from Auckland to Palmerston North using the Dash 8, of which outbound leg was designated flight 703.

At 4:10 a.m. on June 9th, 1995, 40-year-old Captain Garry Sotheran and 33-year-old First Officer Barry Brown reported for duty before a scheduled shift flying back and forth between Auckland and Palmerston North. Pilots disliked the early shift for obvious reasons, and today promised to be especially bleak given the dismal winter weather afflicting the region. Snow had fallen on June 8th, and now dense, low clouds covered much of the North Island, blanketing the mountain peaks of the island’s interior in zero visibility conditions and freezing temperatures.

Nevertheless, the first two out-and-back legs went smoothly, and at 8:17 a.m. flight 703 departed Auckland again with 18 passengers and three crewmembers on board, including the two pilots and flight attendant Karen Gallagher. The flight climbed to its cruising altitude, proceeded normally toward its destination, and began its descent, intending to perform a non-precision approach to runway 07. It was here that a disastrous chain of events began to take shape.

Pilots flying into Palmerston North preferred to land on runway 07 whenever possible, and would try to avoid landing on the reciprocal runway 25, which took more time and came in over the Tararua mountain range, which tended to cause uncomfortable turbulence. Even if the wind favored runway 25, pilots usually would approach runway 07 and then simply circle around to land on runway 25 once the airport was in sight, rather than using the full runway 25 approach.

When flight 703 contacted the Ohakea control center prior to beginning its descent, the controller said, “I’ll advise if the zero seven approach is available.” Concerned that it would not be, Captain Sotheran remarked, “I certainly hope it’s available, I don’t really want to do two five.”

“Yeah,” said First Officer Brown.

“I’ve done it once, that was enough,” said Sotheran.

“It’s quite a long way around there, isn’t it.”

“Yeah.”

The controller cleared the flight to 5,000 feet, and the crew complied, still hoping that they would get the runway 07 approach, which they had already briefed.

Captain Sotheran yawned loudly and said, “Gee, excuse me, I’m tired.”

He would not get any relief from the controller. Another plane wanted to take off on runway 25, which would see it climb out directly into the path of the approach to runway 07, rendering that runway temporarily unusable. At 9:10, she said, “Ansett seven zero three, stop descent at six thousand feet, intercept the one four DME arc for the VOR/DME approach runway two five.”

“Damn,” Captain Sotheran exclaimed. They would have to do the long, uncomfortable approach after all.

Neither runway at Palmerston North International Airport had an instrument landing system, which would provide inbound flights with both lateral and vertical guidance to align with the runway and glide slope. Instead, when visibility was low, both runways used older, less precise VOR/DME approaches. In a VOR/DME approach, a VOR beacon (Very high frequency Omnidirectional Range) allows the plane to align with the runway, but the pilots must keep track of their altitude by ensuring they hit certain heights at certain distances from the airport. Because of the lack of vertical guidance, such procedures are referred to as “non-precision approaches.” The workload on a non-precision approach can be high, and the risk of accidents is known to be greater.

The VOR/DME approach to runway 25 was particularly troublesome. Most VOR/DME approaches included a stage in the middle where a plane could level off to slow down for final approach, but because of the Tararua Ranges rising up to the east of the airport, there was no room for one, forcing planes to come in more steeply. Furthermore, the design of the approach was such that any plane flying it would almost inevitably receive false “terrain” alerts from the Ground Proximity Warning System (GPWS). To mitigate this, Ansett New Zealand instructed pilots flying the runway 25 VOR/DME approach to extend the landing gear and flaps much earlier than usual. This both helped slow the plane and inhibited the ground proximity warning system, which does not issue terrain alerts when the airplane is fully configured to land, since the aircraft is supposed to be flying toward the ground at that point anyway.

To recall quickly how high they were supposed to be at any given distance, the pilots planned to use a shortcut devised by Ansett New Zealand, which was to multiply the distance from the runway (in nautical miles) by 300 feet and then add 400. Reminding himself of the formula, First Officer Brown said, “Three times plus four hundred profile?”

“That’s it,” said Captain Sotheran.

“Yep.”

“And it’s right on the limits, so we gotta stick to that,” Sotheran added, noting that descending any lower than the heights produced by the formula would take the plane too close to the mountains.

Nearing the top of the approach at 6,000 feet, First Officer Brown set the plane’s altitude alert system to inform them when they were nearing the minimum descent altitude (MDA) for the approach — the height, in this case 700 feet, beyond which they could not descend without sighting the runway.

By the time flight 703 aligned with the runway, they were a little bit high and slightly too far to the right, but Captain Sotheran was actively working to get the plane on course.

At 9:20, with the plane about 11 nautical miles from the runway and descending through 4,000 feet, Sotheran called, “Gear down.”

“Okay, selected,” said Brown, moving the landing gear selector lever to the down position. “And on profile,” he added, cross-checking their height and distance. “Ten — sorry, hang on, ten DME we’re looking for four thousand aren’t we, so a fraction low.”

“Check,” said Sotheran.

The plane had caught up with the correct descent profile and was beginning to descend below it. Captain Sotheran increased engine power to slow their descent. “And flap fifteen,” he ordered.

At that moment, the landing gear finished transiting, and Sotheran looked for the three green lights that would indicate that the gear had extended properly. Instead, he saw two green lights and one red one, indicating that the right main landing gear had not extended. “Oh shit,” he exclaimed.

“Actually no we’re not, ten DME we’re — ” Brown started to say, then he too noticed the warning light. “Damn, look at that!”

“I don’t want that!” said Sotheran.

On the Dash 8, the main landing gear extends from a bay inside the engine nacelle on the wing. When retracted, the gear is held in place by an uplock latch, attached to the inside of the nacelle, which wraps around a roller on the landing gear. To release the landing gear, the latch tilts downward, allowing the roller to roll out freely as the landing gear descends. But over time the roller would start to dig a detent in the latch, like a car spinning its wheels on snow. If the detent became too deep, the roller would get stuck and would not roll out of the latch, preventing the landing gear from extending. This is what occurred on flight 703.

In the passenger cabin, the failure of the right main landing gear was plainly obvious, as the gear, or its absence, could be seen through the windows. Breaking off a conversation with a passenger, flight attendant Karen Gallagher decided to go to the cockpit to inform the pilots.

Up front, the pilots were already working the situation. “No, damn yeah that’s not good is it,” said Brown. “So she’s not locked, so alternate landing gear.”

“Alternate extension, you want to grab the QRH,” said Sotheran.

The QRH, or Quick Reference Handbook, contained a procedure which would allow the pilots to extend the landing gear if it failed to extend automatically. As Brown pulled it out, Sotheran said, “Whip through that one, see if we can get it out of the way before it’s too late.”

“Yeah, right.”

“And I’ll keep an eye on the aeroplane while you’re doing that,” he added.

Sotheran had made a decision which would prove to be catastrophic: believing that the landing gear issue could be resolved quickly, he elected to continue the approach. And because of the distraction of the landing gear problem, he had not realized that his earlier thrust increase was insufficient, and that the plane was below the descent profile and dropping.

At that moment, flight attendant Gallagher opened the cockpit door and told the pilots that the right main gear was not down.

“Yeah, we know,” said Brown.

“Thank you,” Gallagher said, returning to the passenger cabin. Not overly worried, she sat down on an armrest and resumed her earlier conversation.

In the cockpit, First Officer Brown began reading the checklist. “Landing gear inop, landing gear malfunction, alternate gear eighteen — oh right, alternate gear extension, approach and landing checklist, pressurization — ”

“Oh, just skip her down to the actual applicable stuff,” Captain Sotheran said. The procedure contained a bunch of routine checks which they had already done. If they were going to get the gear down in time to complete the approach and land normally, then they needed to perform the procedure quickly.

“Yeah,” said Brown, reading off all the redundant items as quickly as possible. “Landing data, altimeters, tanks, belts, smoking… okay, airspeed below a hundred and forty knots? And landing gear inhibit, switch inhibit?”

“Okay, and it’s one forty,” said Sotheran, ensuring they had the correct speed for the procedure.

“Landing gear selector is down?”

“Yep.”

“Landing gear alternate release door fully open,” Brown said, reaching up behind him to open the alternate release door, located in the cockpit ceiling. “…Which it is.”

Taking over radio communications, Sotheran said to the controller, “Ansett seven zero three, established finals Palmerston North.”

“Yeah, thanks, and insert — ” Brown said. “ — Insert this handle…”

First Officer Brown was starting to become confused. The checklist contained two nearly identical items — “Landing Gear Alternate Release Door … Open Fully and Leave Open,” and “Landing Gear Alternate Extension Door … Open Fully and Leave Open” — which contained a critical step, “Main Gear Release Handle … Pull Fully Down” sandwiched in between them. When Captain Sotheran made the radio call, Brown paused to listen to the reply, and when he picked up the checklist again, he returned to the latter door-related step instead of the former, having failed to pull the handle first. Everything after “release handle, pull fully down” was a backup to the backup procedure, which could be used if the alternate release handle didn’t work. It involved opening up a door on the floor, inserting a handle, and manually pumping the gear down, which was unnecessary in this case, but was where Brown had found himself.

“Insert handle at… till… oh yeah, and operate until main gear locks, actually nose gear…” he said.

Keeping a watchful eye on him, Captain Sotheran said, laughing, “You’re supposed to pull the handle.”

“Yeah, it’s got it actually after that,” Brown said, reaching up and pulling the handle. “Yeah that’s pulled, here we go.” He didn’t realize that he hadn’t pulled hard enough to actually release the gear, but the crew was about to have much bigger problems anyway.

Moments later, the ground proximity warning system (GPWS) called out, “TERRAIN! WHOOP WHOOP, PULL UP! WHOOP WHOOP, PULL UP!”

Captain Sotheran instinctively slammed the thrust levers forward and pulled up to climb, but it was already too late. Four and a half seconds after the warning activated, the plane clipped the side of a hill at about 1,800 feet in the Tararua Ranges, sending the Dash 8 careening across a 70-meter wide ravine and into the opposite hillside. The plane bounced hard off the hill, then became airborne again, clearing a second gully before plowing into a third hill with tremendous force. The left wing and tail broke off, and the fuselage, spinning around 180 degrees, slid across a sheep paddock in a hail of flying metal. As terrified sheep fled in all directions, the passengers held on for dear life, even as the wings ripped away, the floor ruptured upward, and the ceiling collapsed, sending the overhead bins crashing down on their heads. And then, after just a few harrowing seconds, what was left of Ansett New Zealand flight 703 came to a halt in a field, surrounded by the eerie twilight of the blowing fog.

Miraculously, the majority of the 21 people on board survived the crash, although most had suffered serious injuries. Three people were dead, including two passengers as well as flight attendant Karen Gallagher, who was still sitting on an armrest talking to a passenger when the plane impacted the mountain, causing her to be thrown to her death.

Many of those who did survive, including both pilots, had suffered concussions when their heads struck the seats in front of them, and they only came to their senses slowly. Had there been a fire, the death toll would have been much higher, but fuel liberated from the right wing had mostly burned up in a flash explosion on impact without resulting in a major blaze. That gave the passengers plenty of time to struggle their way out of the fuselage, which was choked with collapsed overhead panels, dislodged seats, and other debris.

At Palmerston North Airport, the controller tried and failed several times to contact flight 703. Becoming worried, he called the Ohakea controller, who confirmed that the plane had disappeared from radar. At 9:26, four minutes after the crash, a search and rescue mission was launched in the area near the airport, initially concentrated about four nautical miles short of the runway where the Ohakea controller thought she last saw the plane. Unknown to them, the plane was actually twice as far away, hidden up in the clouds in the Tararua Ranges.

The search had only just begun when local police received a call reporting a plane crash. Police told rescuers that the call came from a witness, and it was only once a rescue coordinator called the number the police had given them that they realized the man on the other end of the line was not a witness, but a survivor of the crash! Businessman and flight 703 passenger William McRory was one of relatively few people in New Zealand in 1995 to own a cell phone, and to his surprise he was able to not only find it intact after the crash, but managed pick up a signal as well. Unsure of his location, he attempted to describe his surroundings: the plane had come to rest in what appeared to be a sheep paddock, they were in clouds, the terrain was uneven, and it was very cold. Unfortunately for the rescuers, this initial description was not much help — New Zealand has significantly more sheep than people, and the presence of a sheep paddock hardly narrowed things down.

Meanwhile, some passengers began to return to the plane, hoping to find first aid materials, locate warm clothes to protect against the bitter cold, and help free passengers still trapped in the wreckage. Unfortunately, they were met with little in the way of success. Although they attempted to use blankets and airplane insulation to stave off the cold, there wasn’t enough to go around, and the risk of hypothermia only continued to increase. And while the plane did have first aid kits, they were not prominently labeled and the passengers failed to find them. It was at this point that as a group of survivors approached the plane to search for trapped passengers, spilled fuel near the right engine ignited into a sudden flash fire. Although it dissipated quickly, the explosion engulfed passenger Reginald Dixon, causing severe burns to 80% of his body.

At the same time, a passenger sent to look for landmarks noticed a very large sheep pen, and this observation was relayed via the cell phone link to rescuers, one of whom knew that only one farm in the area had a pen that big. The challenge then was to find it. With dense fog in the area, search helicopters had to fly very carefully, relying on instruments to keep away from terrain, and it was impossible to search visually for the landmark in question. Their lucky break came when a weak signal was detected from the plane’s emergency locator beacon, allowing helicopters to follow the signal until the remains of the plane came into view through the swirling clouds. Only now, one hour after the accident, were paramedics able to make their way to the crash site to help the badly injured survivors. Despite the conditions, everyone had been brought to hospital by 12:07, less than three hours after the crash.

By the time everyone had been accounted for, it was clear that three people had died while eighteen initially survived. However, Reginald Dixon, the most seriously injured passenger, was unable to recover and died from his severe burns two weeks after the accident, bringing the final death toll to four. And in addition to its human victims, the crash also killed several hapless sheep which failed to get out of the way in time.

Investigators would later note that while the survival of so many passengers was fortuitous, their ability to survive after the accident could have been enhanced. Most notably, the location and signage of the fire extinguishers and first aid kits were chosen based on the assumption that a crewmember would access them, but in this case all the crewmembers were either dead or too badly injured to assist. The first aid kits, which would have been quite helpful, were marked with nothing more than a small green cross and were almost impossible to find if one didn’t already know where they were. This was a holdover from an earlier era when airplane first aid kits contained narcotics, causing them to be stolen frequently; however, the kits hadn’t contained any narcotics since 1987, and investigators would eventually recommend that they be made more conspicuous.

◊◊◊

Excluding the sheep, the four fatalities made this the most serious crash of a New Zealand commercial airliner since 1979. The challenge of investigating the accident was therefore placed on the most experienced shoulders available: those of Ron Chippindale, head of the newly created Transport Accident Investigation Commission (TAIC), and his team of investigators. (Readers may remember Chippindale as the author of the first, largely discredited report on the Erebus disaster, but it should be noted that by 1995 he was considerably more experienced and there is no reason to doubt his conclusions.)

From the physical evidence at the crash site, it was immediately clear to the investigators that while the left main gear and nose gear were extended at impact, the right main gear was not. Survivors of the crash confirmed this in their testimonies.

The probable reason for this failure was really quite simple: the uplock latch had worn down too much where the roller rested inside it, causing the roller to become stuck instead of slipping out when the latch was opened. More interesting was the question of what the airline and the manufacturer had done to prevent this. As it turned out, problems with the Dash 8 landing gear were well known among operators and at de Havilland Canada. In 1992, the manufacturer released a new version of the latch which was made from a harder material and would not wear down so easily, along with a service bulletin explaining its installation. However, the modification was not mandatory as long as operators inspected the latch for wear every 3,000 flight hours, and the latches were not provided for free, although de Havilland Canada did offer a discount. For its part, Ansett New Zealand initially decided to stick with the inspections rather than buying the new latches, and by the time they reconsidered in December 1994, the latches were almost out of stock.

In light of the limited number of available parts, Ansett had to economize. In the end, the airline decided to install the new latches on the left main gear of its three Dash 8s, and modify the right main gear on each airplane later, once the latches were back in stock. This decision was made because Ansett New Zealand had experienced significantly more problems with the left main landing gear than with the right. On the accident airplane ZK-NEY and its sister ship ZK-NEZ, there had been a total of eight incidents since 1988 in which the main landing gear was slow to release, and seven in which it did not drop at all and had to be extended using the alternate procedure; and out of these 15 incidents, 12 had involved the left side.

Although this was the correct decision given the data available, it meant that the right main gear on the accident airplane continued to use the old latch, which eventually wore down until it got stuck. The latch had been inspected on May 2nd of that year, but the technical instructions used by the inspectors did not specify how much wear was acceptable. By the time of the accident, the worn area was 0.15 millimeters deep and about 5 millimeters wide, well outside the manufacturer’s limits, but even if this was the case at the time of the inspection, the inspectors may not have been able to judge whether the wear was excessive without access to the manufacturer’s numbers.

All of this having been said, the failure of the right main gear to extend should not have been an emergency situation. Every other time this happened at Ansett New Zealand, the crews involved had extended the gear using the alternate procedure and continued to safe landings. So what went wrong this time?

In fact, far more significant than the failure itself was the distraction it created in the cockpit. Already engaged in a difficult non-precision approach in bad weather, a mechanical problem was the last thing the crew needed. At the time the landing gear failure occurred, the plane was below the descent profile and slightly too far to the right, and the pilots’ full attention would have been required to keep the plane on course. Their workload was further exacerbated by the airline’s policy of not using the autopilot or the flight director — which suggests optimal control inputs to achieve a desired altitude, heading, and/or descent rate — while on non-precision approaches. Considering the circumstances, investigators had to question Captain Sotheran’s decision to proceed with the approach instead of climbing to a safe altitude and entering a holding pattern until they fixed the gear. Even though it was within his rights to make that call — no official procedure or company policy stated otherwise — it represented poor judgment, and may have been born out of a desire to get the flight over with and avoid having to do the troublesome runway 25 approach all over again.

The desire to get the procedure finished before the plane touched down created a time constraint which forced the pilots to complete a large number of tasks during a very short period. Inevitably, some of these tasks fell by the wayside. Most critically, the pilots failed to monitor their altitude, allowing the plane to descend below the approach profile until it crashed into the ground. Shortly before the failure occurred, First Officer Brown stated that they were “on profile,” which was momentarily the case, but they were actually descending too steeply and soon passed beneath it. Brown did point out that they were a “fraction low,” and Sotheran responded by increasing engine power to 35%, but this was not enough to keep the plane on profile, in part because the mountains were creating a downdraft with a strength of 410 feet per minute. The downdraft was hardly dangerous, but it could have caused Sotheran to underestimate how much thrust he needed to add.

This error would have been quickly noticed had the landing gear not failed just a few seconds later. Although Sotheran did state his intention to “keep an eye on the aeroplane,” he actually spent most of the remaining time until impact assisting Brown with the alternate gear extension procedure. This task was complicated by the confusing design of the checklist, which contained two nearly identical steps without any numbering, causing Brown to lose his place and do some tasks out of order. And the situation may have been made even worse by fatigue, given the early start to the shift, and the fact that Captain Sotheran had been heard on the CVR saying that he was tired — although the final report, which ruled out any influence of fatigue on the crew’s mistakes, bizarrely made no mention of this highly indicative statement.

In any case, because of the breakdown of effective flight path control, the investigators sought to determine what expectations the crewmembers might have had regarding their responsibility for monitoring the airplane’s altitude while dealing with an abnormal situation. At Ansett New Zealand more broadly, pilots did not agree on whether the captain would have taken on that responsibility when the first officer started the checklist, or whether the first officer would have been expected to keep monitoring the altitude in between checklist items. Captain Sotheran told investigators that he thought First Officer Brown would continue to monitor the instruments, but if this was the case he should have spoken up when Brown did not make any routine altitude callouts. For his part, Brown said he was never taught in training that he should continue monitoring the instruments while completing an abnormal checklist, and did not do so.

These divergent expectations about their respective roles during the application of the abnormal procedure led to a situation in which no one was keeping track of the airplane’s altitude. That such a situation could arise led investigators to examine the pilots’ crew resource management (CRM) training, which should have given them the skills needed to delegate tasks effectively.

It turned out that First Officer Brown had only recently switched to the two-pilot Dash 8 after a career spent flying single-pilot operations in the hinterlands of Papua New Guinea. To facilitate his transition, he had received a grand total of four hours of CRM training, most of which was spent analyzing the mistakes made by crews in previous accidents caused by poor pilot coordination. The training included no simulator exercises because the nearest Dash 8 flight simulator was located more than 11,000 kilometers away in Seattle, Washington, and the airline only sent pilots there when absolutely necessary. Captain Sotheran had more exposure to this type of training and was more experienced in two-pilot operations, but the quality of his CRM instruction would have been equally low. The end result was that while the pilots knew the basic principles of crew resource management, they were not sufficiently well-versed in the topic to put those principles into practice in a situation where the distribution of tasks within the cockpit had become unclear.

In the end, 120 seconds of distraction allowed the plane to drift below and to the left of the approach profile until it struck the ground. But even so, calculations showed that the GPWS should have sounded a “TERRAIN” alert between 15 and 18 seconds prior to impact, leaving plenty of time to avoid the mountain. Instead, it only activated 4.5 seconds before impact, and although Captain Sotheran reacted with above average speed, there was no chance for him to avoid the crash.

The early-generation GPWS on the accident airplane worked by analyzing the rate of closure with terrain directly below the aircraft as derived from radio altimeter data. Investigators therefore examined a number of potential failure modes of the radio altimeter which could have led to the late warning. Interference from a nearby transmission tower or from cell phones was ruled out because these devices didn’t transmit on a frequency anywhere near that of the radio altimeter. Although they did find that the radio altimeter antenna had been erroneously painted over, tests showed that the paint did not obstruct the signal, and this was also ruled out. In the end, the only scenario tested by investigators which could reproduce the timing of the GPWS warning was a transient failure of the radio altimeter about 20 seconds before impact. Although there was nothing mechanically wrong with the device, investigators speculated that a random software error could have taken it offline for just long enough to inhibit the warning until it was too late. Nevertheless, the true cause of the late warning was never determined with certainty.

Several other mechanisms also existed which could, in theory, have warned the crew that they were too low. The airplane’s altitude was displayed on the radar screen at the control center in Ohakea, but by the time of the accident control of the plane had been handed over to Palmerston North tower, which did not have radar (although its installation had been planned for the near future). Although Ohakea continued to track the plane, the center was neither required nor equipped to ensure its separation from terrain, only from other aircraft. However, a device existed which could have enabled this, called the Minimum Safe Altitude Warning system, or MSAW. The system can be installed at an airport in order to detect when an approaching plane is too low, sounding an alarm in the control tower. However, even though MSAW systems were in widespread use in the United States, no airport in New Zealand had installed one, because the Civil Aviation Authority (CAA) was not convinced that they were reliable, and the airport authority was worried about the legal consequences of assuming liability for keeping airplanes away from terrain, which under New Zealand law was considered the sole responsibility of the pilot.

The pilots also might have gotten an alert from their altitude alerting system, but it had been set, per company procedure, to inform them when approaching the minimum descent altitude for the entire approach, which was 700 feet — below the height of the terrain at the accident site. As such, the device proved useless in preventing the accident. Unfortunately, Ansett New Zealand had judged it impractical to set the altitude alerting system for each intermediate step-down height on the approach to runway 25, because the system would not work correctly if it was set to a value within 1,000 feet of the plane’s present altitude, and most of the “steps” were not more than 1,000 feet apart. Alternatively, the pilots could have set the radio altimeter to issue an alert when the plane came within a certain distance of the ground — a practice which used to be common in the time before ground proximity warning systems, but had since fallen out of favor. Although there was nothing preventing the pilots from setting up a radio altimeter alert, it was not company policy to do this, so they didn’t.

By this point investigators were (probably) asking what was company policy. On the whole, Ansett New Zealand’s procedures and policies seemed highly questionable. In addition to the airline’s failure to utilize systems that could have added redundancy to the GPWS, the practice of not using the autopilot or flight director on non-precision approaches made the pilots’ jobs harder in exchange for little operational benefit, and quite probably contributed to the accident by robbing the crew of yet another indication that they were too low. Policies describing who should do what in a variety of abnormal situations were also conspicuously missing. And perhaps most worryingly, there was some doubt as to whether the airline had actually conducted all of the training that it claimed. Despite documents showing that all Ansett New Zealand pilots received training on GPWS response procedures and the full alternate gear extension procedure, First Officer Brown said he had not received training on either of these topics, and both pilots answered questions about these procedures incorrectly, adding weight to their claims. The official report did not explicitly call out this suspicious discrepancy, but its presence is nonetheless obvious to any astute reader.

The airline also could have indirectly prevented the accident by taking a more proactive approach to the recurring problems with the Dash 8’s landing gear. The best method for tackling such an issue would be a safety management system (SMS), which aggregates anonymous reports and other flight data to identify and rectify recurrent difficulties before they result in an accident. Ansett New Zealand had installed a primitive safety management system, in the form of a Flight Safety Coordinator whose job description was somewhat similar to the standard definition of an SMS. However, the Flight Safety Coordinator, although an experienced pilot, had no formal flight safety training and was given no real means to carry out his directive. In practice, he was not part of the decision-making flow regarding flight safety, which was mostly handled by regional managers. No one reported the frequent landing gear problems to him, nor did he take any action in relation to the issue, such as reminding pilots to practice the alternate gear extension procedure; instead, pilots mostly found out about such issues by word of mouth, which was not an effective means of dealing with the unsafe trend. On the other hand, had some formal action taken place, the pilots might have been better prepared for the failure, reducing the distraction which prevented them from noticing their low altitude.

Considering all of the above, it could be argued that Ansett New Zealand ran a somewhat ad-hoc operation with a “nothing bad ever happens” attitude. It would have been the responsibility of the CAA to detect and correct this tendency, but from the information in the official accident report, it seems that this culture extended to the regulator as well. In the investigators’ opinion the CAA was not conducting nearly enough audits of Ansett New Zealand to discover its deep-seated problems. One reason for this was that the CAA was required by law to self-fund its audits, meaning that it had to charge the airline for the privilege of being reviewed for compliance. This incentivized the agency to spend as little time on each audit as possible in order to avoid the perception that it was overcharging the airlines.

Besides the CAA’s inadequate inspections, New Zealand’s aviation regulations in 1995 were blatantly anachronistic and clearly had not been updated in many years. Turboprop aircraft were not required to have ground proximity warning systems (a requirement in the United States since 1975), nor was any New Zealand-registered airplane required to have a cockpit voice recorder (a requirement in the United States since 1967). In practice, every passenger airplane had these systems, because planes were generally manufactured in accordance with US standards, and there seemed to be little urgency to update New Zealand’s own regulations. But perhaps most surprising of all was that New Zealand had not even formally adopted Annex 13 to the Chicago Convention, the basic framework which is supposed to govern how countries conduct air crash investigations, and which was supposed to have been agreed upon by every member state of the International Civil Aviation Organization clear back in 1944.

It was in part this failure to formally adopt Annex 13 which enabled one final twist in the story of flight 703. Following the publication of the official report by the TAIC, which cited Captain Sotheran’s failure to maintain a safe altitude as the probable cause of the accident, prosecutors moved to charge Sotheran with four counts of manslaughter. Needless to say, this was a gross oversimplification of the cause, which, as should by now be clear, was deeply rooted in systemic problems at the airline and in New Zealand aviation as a whole. In fact, prosecutions of airline pilots involved in accidents, absent obvious gross negligence, are explicitly discouraged by international bar associations and have been criticized by air safety experts because they disincentivize telling the truth to investigators.

But while such prosecutions nevertheless happen regularly around the world, this particular case was especially egregious. According to Annex 13 to the Chicago Convention, it is illegal to use testimony given to a safety investigation, including in the form of a cockpit voice recording, as evidence in a criminal case against a person involved in an aircraft accident. But because New Zealand had not enshrined Annex 13 into law, prosecutors were able to use the CVR transcript, appended to the TAIC’s report, to make their case that Captain Sotheran had committed manslaughter. This misuse of the findings of a safety investigation outraged both the Air Line Pilots Association and the investigators themselves, because it violated the basic agreement which allowed the installation of cockpit voice recorders in the first place — namely, that their contents would not be used against pilots in court.

During the trial, which took place in 2001, Captain Sotheran was forced to defend himself by traditional means, since the trial was legitimate under New Zealand law, international law notwithstanding. It was in this context that he put forth an argument that his altimeter had malfunctioned and jumped 1,000 feet downward before his eyes, a claim which seemed engineered as an alibi — an understandable decision given that any admission of inattention could have been interpreted as an admission of guilt (the very scenario which makes this kind of trial so deleterious to safety). There was no evidence of this type of malfunction, nor was there any way to prove that it had or had not occurred. Nevertheless, the jury was convinced, and in a victory for pilots, investigators, and aviation safety itself, Captain Sotheran was acquitted on all counts on June 1st, 2001. Although he never flew in New Zealand again, he did return to the pilot’s seat, finishing his career overseas — a bittersweet ending, but the best he could have hoped for.

Despite everything, the accident resulted in a number of improvements to aviation safety in New Zealand. The airport authority decided to begin installing MSAW systems; the CAA hired more audit staff; and Ansett New Zealand made several changes, introducing a requirement that pilots abandon the approach if a technical failure occurs; integrating its safety management system into day-to-day operations; improving training for flight safety personnel; commissioning the construction of a Dash 8 flight simulator in Australia; adjusting the wording of the alternate gear extension checklist; and instructing pilots to set radio altimeter alerts on non-precision approaches. However, the longevity of Ansett’s changes proved short, as the airline went bankrupt and permanently ceased operations in 2001.

Today, the crash of Ansett New Zealand flight 703 should serve as a cautionary tale for pilots, airlines, and governments. It underscores the importance of good judgment and avoiding undue haste, the necessity of clear and unambiguous policies about even trivial matters, and the senselessness of turning a safety investigation into a criminal prosecution. But it is also a tale of resourcefulness, heroism, and survival against long odds. In the aftermath of the crash, passengers acted commendably, working together to keep each other alive and help rescuers find the airplane, despite the fact that nearly everyone was seriously injured. New Zealand authorities in particular recognized Reginald Dixon, who perished upon returning to the plane to help those trapped inside, an act of sacrifice for which he was posthumously awarded the New Zealand cross, the country’s highest civilian honor. And although he was not a hero, we should also spare a thought for Captain Garry Sotheran, whose pain of guilt was no doubt greatly amplified by the unnecessary six-year legal ordeal to which he was subjected. In the future, therefore, let us not make the mistake of confusing retribution for justice.

_________________________________________________________________

Join the discussion of this article on Reddit!

Visit r/admiralcloudberg to read and discuss over 200 similar articles.

You can also support me on Patreon.

--

--

Analyzer of plane crashes and author of upcoming book (eventually™). Contact me via @Admiral_Cloudberg on Reddit or by email at kylanddempsey@gmail.com.

Love podcasts or audiobooks? Learn on the go with our new app.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Admiral Cloudberg

Admiral Cloudberg

Analyzer of plane crashes and author of upcoming book (eventually™). Contact me via @Admiral_Cloudberg on Reddit or by email at kylanddempsey@gmail.com.