Airbus 340-600 Crash: A Study on HFACS

Etihad Airbus A340-600

Location: Toulouse Blagnac Airport, France at 1610 hrs (UTC)
Date of Accident: 15 November 2007
Aircraft Type: Airbus A340-600
POB: 9
Incident: Engine ground test

Synopsis

On 15 November 2007, an Airbus A340-600 due to be delivered to Etihad Airways crashed during ground engine test at Airbus' facilities in Toulouse Blagnac International Airport. The brand new US$250 million aircraft, damaged beyond repair. was written off. [1]

Persons on the flight deck during the ground test Ground test technician on the right seat in charge of running the test, an Airbus employee Customer representative on the left seat, on board to observe compliance to the required test parameters Flight test engineer on the jump seat to observe, Airbus employee Sequence of Events [2] The aircraft had just completed a static ground run to test various system. After stopping and inspecting the engines, the technician started the engines again for another run at full power to find the origin of oil leaks. About three minutes after power up, the customer representative on the left seat sensed the aircraft moving forward and informed the Airbus technician in charge of the controls. The ground test technician acted on the brake pedals and then released the parking brakes. Since the aircraft continued to move forward, the technician turned the nose steering wheel to avoid crashing into the test-pen wall. The nose wheel gear skidded sideways as the aircraft accelerated. The aircraft crashed in the slope of the test-pen wall, the forward fuselage broke and fell down on the other side. The flight test engineer on the jump seat pulled back the throttle two seconds after the impact. There were thirteen seconds between the start of aircraft movement and the collision with the wall. Engines No. 1 and No. 2 hit the wall and were severely damaged The Numbers 3 and 4 engines could not be shut down after impact because the throttle control connection had been severed. No. 4 was finally shut down over two-and-a-half hours later when enough water and fire-fighting foam had been pumped to snuff it out. The No. 3 engine died 9 hrs later when it ran out of gas, it was too jammed into the wall to get any water/foam into it.

(Image embedded from Flightglobal on 17 Aug 2009)

Investigation

According to the French Bureau d’Enquetes et d’Analyses (BEA), "a lack of detection and correction" of violations to test procedures caused the accident when the four Rolls Royce Trent 500 engines, producing 56,000 pounds of thrust each were being tested at high power with the wheels unchocked. The report added that when the aircraft suddenly surged forward, the ground test technician focused on the braking system and attempted to steer away from the test-pen wall instead of reducing the engines' thrust. The impact of the 220-tonne aircraft moving at 55kmh nearly split the aircraft in two. [3] Lessons from the Accident Using Human Factors Analysis and Classification System (HFACS) to defined and analyze the primary causal factor of the accident, four levels of human failure were identified: [4] 1. Unsafe Acts (Active Failure)- * Errors - When the aircraft moved, the ground technicians was fixated in applying the brakes and steering the nose wheel instead of reducing the power by retarding the throttle. The full power of four engines is almost exactly equal to the braking power of the A340s parking brake and the frictional coefficient of the test area’s tarmac, hence the aircraft only moved when the vibrations of the aircraft and the burning off of fuel lessened the overall braking coefficient.

(Image embedded from Flightglobal on 17 Aug 2009)

* Violations - During the test for detecting oil leaks, the procedure to apply thrust on two engines only was not systematically carried out. All four engines were brought to full power, procedures required running up two engines – the one leaking and one on the other wing (to prevent torquing and yawing of the fuselage).The Aircraft Maintenance Manual (AMM) and the CAM (Customer Acceptance Manual) state that the engines tests must be carried out with the use of wheel chocks for the main landing gears. 2. Preconditions for unsafe acts - Loss of situational awareness and complacency. The Airbus technician in charge of the engine run test was unaware that the aircraft was moving until the customer representative told him so. He testified to have often carried out this kind of test, but at a higher aircraft weight. 3. Unsafe Supervision (Latent Failure) - Airbus technicians admitted that some test are conducted outside the scope of the Customer Acceptance Manual due to pressure from the customers to check some details. The presence of representatives of the customer on board during the delivery phases can create pressures inducing testing technicians to overlook their frame of reference. 4. Organisational Influences (Latent Failure) - There were oversights in safety programmes and organizational processes, recordings of video cameras from several days before the accident show that some test are carried out with wheel chocks and some others without even though reference documents require using wheel chocks during engine test. The lack of a detection process and deviation correction in the ground test procedure, promoted the operation of the test outside of the established procedures.

(Image embedded from Brisbane Times on 17 Aug 2009)

References

1. Airline World "Etihad Airbus Crashes Into Wall During Testing" 16 November 2007 Retrieved from Airline World

2. BBC News "France Investigates Airbus Crash" 16 November 2007. Retrieved from BBC News

3. Gale, Ivan. "'Unsecured Wheels' Caused Airbus Crash." The [Abu Dhabi] National 21 December 2008 Retrieved from The National

4. Kaminski-Morrow, David "Toulouse accident occurred as Airbus A340 was exiting engine test-pen" 19 November 2007 Retrieved from Flightglobal

Want to know more?

Human Factors Analysis and Classification System

An overview of Human Factors Anaysis and Classification System

Accident Photos

This page shows photos and comments on the Airbus 340 accident.

Article on A340 Accident

---

Contributors to this page

Authors / Editors

AvMan

Proof-readers