It's not often a multi-million dollar airplane is considered to be damaged beyond repair. Often, the decision to abandon any attempt to fix the plane is based on its age and years of service - the lower value of a more well-used plane disrupts the economics required to invest in repair.

But for a brand new Airbus A340-600, worth $275.4 million ($316.8 million today), to be written off as beyond economical repair must mean something very significant happened. And it did.

What happened to Etihad's A340-600?

Etihad ordered the A340-600 as part of a commitment in 2004, estimated to be worth over $7 billion in total at list prices. In all, there were 24 planes included in that order, ranging from 12 A330-200s to four A380s and some A340-500s as well as the -600s. Later on, Etihad switched the -500s for more of the -600s, taking its entire orderbook with Airbus for the type to eight planes. Unfortunately for Etihad, it would only ever receive seven.

The A340-600 was not just the longest in the family but, at the time of its launch, also the longest in the world. It measured 75.36 meters (247 feet) from nose to tail. Etihad was keen to use this huge size to its advantage, leveraging its hub and spoke model to feed passengers between east and west through its hub in Abu Dhabi.

At the time of the accident, Etihad had taken delivery of just two of its order of eight A340-600s. It's third carried Airbus test registration F-WWCJ, and would have flown as A6-EHG with Etihad if it had ever made it out of Toulouse.

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The A340-600 never made it as far as Abu Dhabi. Photo: Getty Images

According to ch-aviation.com, the aircraft had been in testing for nearly two months before the incident. Its first flight took place on September 21st, 2007, powered by four Rolls-Royce Trent 556-61 engines. ATDB.aero adds that its delivery to Etihad would have been exactly two months later, on November 21st. However, six days prior to this, catastrophe struck.

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Crashed during engine tests

Before an aircraft makes its way from the manufacturer to the customer, it has to pass a series of tests. On November 15th, 2007, F-WWCJ was in a test pen at Airbus's headquarters in Toulouse, France for the purpose of undergoing stationary engine testing.

According to Aviation Safety Network, a team of engineers began these trials at 15:19 local time. Reports suggest that their purpose was to monitor the possibility of oil leaks. However, and crucially, the engineers had not properly secured the aircraft with chocks.

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Etihad Airbus A340-600 Photo: Getty
The damaged aircraft remained in place for several days and nights. Photo: Getty Images

To begin with, this didn't result in anything untoward, with the Engine Pressure Ratio (EPR) being between 1.04 and 1.22 until 15:58. Following an hour's break, testing recommenced with the engines running at higher thrust levels, with the EPR being as high as between 1.24 and 1.26 for three minutes. Eventually, this caused the unchocked aircraft to move.

According to Aviation Safety Network, the aircraft was in motion for 13 seconds before being brought abruptly to a stop. While engineers applied the brake pedals within seconds of the movement beginning, they did not reduce the thrust. This meant that, despite turning the plane to the right, it collided with the pen wall at around 30 knots (55 km/h).

As the aircraft was not restricted with chocks, one might wonder why it didn't begin to move sooner. The reason for this was that its parking brake was applied, and therefore only failed when the thrust was increased beyond its capabilities. And then, when the engineers applied the brake pedals as the plane started to move, the parking brake deactivated entirely, causing the plane to actually accelerate.

Etihad Airbus A340-600
Steering the aircraft actually limited the effectiveness of its brakes. Photo: Mark Harkin via Flickr

Damage to the plane and its occupants

As the aircraft turned 37 degrees to the right, it took just seven seconds to accelerate from four to 31 knots. This surge meant that when the aircraft came to impact the pen's retaining wall, the impact on it and its occupants was significant.

As is clear from the photographs of the incident, the collision pushed the aircraft's nose up and through the concrete barrier. This caused extensive damage to the forward part of the quadjet's fuselage, with the cockpit ultimately breaking off. The left engines also took a hit, and the angled wall caused the tail to hit the ground as well.

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There's no coming back from damage like that. Photo: Getty Images

The collision also had safety and health implications for the aircraft's occupants. All in all, there were nine people onboard F-WWCJ when it collided with the test pen's concrete retaining wall. Of these, Aviation Safety Network observes that five received injuries, four of which were serious.

The fact that the impact of the collision sheared the plane's cockpit from its fuselage meant that writing the aircraft off was the only viable option. ATDB.aero notes that the wreckage was dismantled in 2008, with the tail briefly being displayed at the Champs Elysées in Paris. Meanwhile, Virgin Atlantic reportedly used part of it as a cabin crew trainer.

The investigation and aftermath

The incident was, of course, subsequently the subject of an investigation from France's Bureau of Enquiry and Analysis (BEA). The BEA's inquiry found that the collision was the culmination of test procedure violations. It added that a lack of detection and correction of these violations had resulted in F-WWCJ's terminal crash.

But why did those onboard the aircraft not think to reduce its thrust in tandem with their brake applications? This is where the human factor comes into play, with the BEA ultimately determining that,

"...surprise led the ground-test technician to focus on the braking system, so he did not think about reducing the engines' thrust."

Etihad Airbus A340-600
Etihad used another A340-600 to promote the Abu Dhabi Grand Prix. Photo: Maarten Visser via Flickr

Ultimately, Etihad canceled its order for the eighth A340-600. It took delivery of seven in total, with all arriving between 2007 and 2009. By 2018, all its A340-600s had been retired.

Did you know about this incident? Are you aware of any aircraft that have suffered similar fates? Let us know your thoughts in the comments.