1.14 Information on organizations and management
The aircraft had completed the necessary tests for the certificate of airworthiness. It was in the phase of delivery to the customer.
The delivery of an aircraft to a customer is effected on the basis of the CAM 'Customer Acceptance Manual) drawn up by Airbus. This manual consists of three sections. The first section concerns the checks to be performed on the ground, without the engines running. The second concerns the engine ground runs. Finally, the third one deals with acceptance flight testing. The manual takes the form of a list of actions and checks that the manufacturer proposes to carry out in the presence of the customer. In practice, the customer can request additional checks.
In the customer delivery manual, the seat occupied by the representative of the customer during ground tests is not specified. In practice, the representative of the customer is generally in the left seat. He takes note with the Airbus technicians of the parameters to be monitored.
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 MLG.
The CAM uses tasks listed in the AMM. Thus, there is in the AMM a procedure to search for oil leaks called “Fuel and Oil Leak Test”. This procedure calls for testing with two engines in operation. These engines must be the symmetrical engines of each wing. For the engine on which the oil leak is sought, the maximum thrust value of the day must be applied (1.25 EPR that day, corresponding to the maximum value for this type of test). For the opposite engine the EPR value to be applied is 1.145. These actions are carried out by memory.
Production oversight
Until 21 July 2008, on behalf of the DGAC (4), the "Groupement pour la Sécurité de l'Aviation Civile" (GSAC) provided oversight of Airbus production in France for the following phases:
• manufacture of aircraft components
• aircraft assembly
• ground testing and flight testing
• delivery to customers
Note (4): This oversight is today the responsibility of the European Aviation Safety Agency. Under the terms of an EASA contract, the GSAC will continue to act under the authority of the DGAC.
This oversight continues until the issuance of the certificate of airworthiness (aircraft to be registered in France), the certificate of airworthiness for export (aircraft exported outside the EU), or the certificate of conformity to type (aircraft exported to another EU country). The issuance of these documents takes place after ground and flight testing, the delivery flight to the customer and the transfer of ownership. The purpose of the GSAC oversight is to ensure that the aircraft is delivered in accordance to certified standards and in an airworthy state. It does not ensure the safety of ground and flight testing.
The GSAC has no personnel with specific skills for the supervision of ground and flight testing. In France, the Flight Test Center (CEV) is responsible for testing activities of civilian and military aircraft. A 1st of June 1999 regulation directs organizations engaged in testing and acceptance of aircraft to file with the director of CEV, an operations manual laying down rules and procedures to implement these activities so that air testing and acceptance tests are carried out under satisfactory conditions of safety. This regulation does not provide for oversight by the authority of the application of the procedures described in the manual. The manual filed by Airbus does not address the ground test procedures.
Training of ground test technicians
After a theoretical phase of familiarization with the aircraft systems, trouble-shooting and functional tests, ground test technicians take training courses for cabin crew, courses in radiotelephony and taxiing.
The next phase is practical during which the trainee works with an instructor. The following points are notably addressed:
• ground tests
• low speed taxi
• participation in accelerate-stops
• production flights
• carrying out tests in the Customer Acceptance Manual and associated tests
• use of technical documentation and software
• training in pressurization tests.
Practical parts of this training are accomplished in the airplane and in the simulator.
A refresher session is performed in a simulator every two years for all ground test technicians.
1.15 Additional information
1.15.1 Testimonies
Ground test technician on the right seat
After conducting the ground tests, the client company technicians noticed an oil seepage on the pipe of one engine. Hence, the ground test technician decided to carry out another test before leaving.
He increased the thrust in order to heat up the engine oil. After approximately three minutes, as he was looking inside the cockpit, he heard the person sitting on the left seat announcing that the plane was moving. He then noticed the movement himself. He released the parking brake in order to use normal braking. When the aircraft continued to move forward he thought there was a brake problem. He then tried to change the trajectory of the aircraft using the NWS. He testified to have often carried out this kind of test, but at a higher aircraft weight.
Aeronautical technician on the left seat
During the last test at high thrust, he perceived the motion of the aircraft by looking outside. He felt jolts that he believed were caused by the brakes. He noted the ineffectiveness of the NWS action. He did not touch any controls.
He specifies the high thrust test was performed to thin the oil in order to detect any seepage.
Flight test engineer on the jump seat
He attended as an observer for his first A-340-600 delivery. During the last high thrust test, he heard the person on the left seat announcing that the plane was moving. Given the vibration environment generated by the high thrust setting, he was unable to perceive the accelerations caused by the aircraft movement. He only remembers to have grabbed and retarded the thrust levers when seeing the wall very close.
The ground personnel
They watched the end of the tests. Before leaving the testing area, the technician on the right seat told them to move further away from the aircraft as he was going to proceed to a last high thrust test. They positioned their vehicle in front of the aircraft then moved further away on the side when thrust was set. They then saw the plane moving, initially slowly then faster. They saw it hit the wall. They raised the alarm.
Wheel chocks are not always used because their use is restrictive. Sometimes, it happens they stay trapped under the tires after the tests. This requires the plane to be pushed back to remove them.
Note: It is clear from discussions with other Airbus technicians that this kind of test, including with 4 engines at high thrust, are frequent. All confirm that the use of wheel chocks is not systematic. Finally many emphasize the pressure from the customers to go and check some details. This leads sometimes to conducting tests outside the scope of the Customer Acceptance Manual.
2- ANALYSIS
2.1 Test procedure
Although the reference documents require using wheel chocks during engine tests, the investigation showed they were not systematically used. Similarly, during the test for detecting oil leaks, it often seems that the procedure to apply thrust on 2 engines only is not respected.
The industrial and commercial issues that are associated with the delivery activities may lead to induce time pressure on testing technicians during this phase.
The presence of representatives of the customer on board during the delivery phases can create pressures inducing testing technicians to not respect their frame of reference.
2.2 Reactions in the cockpit
The ground test technician’s concentration was on the braking system for about ten seconds. He did not think to retard the thrust levers. This can be explained by his focusing on the braking problem, by the dynamics of the situation and by the lack of training for this kind of situation.
The persons in the left seat and jump seat were present only as observers. The aeronautical technician in the left seat did not intervene on the controls until impact.
The flight test engineer intervened, but late, to retard the thrust levers. This can be explained by his statute, the fear of interfering with the actions of the technician and also by the dynamic of the situation.
2.3 Oversight of these activities
The regulations relating to the tests and acceptances does not envisage oversight by the regulating authority of the activities of tests and reception of aircraft. Thus the control of these activities is implicitly delegated to the manufacturer.
3. CONCLUSIONS
3.1 Findings of investigation
• The aircraft, including its braking system, operated in accordance with its specifications
• The accident occurred in the delivery phase of a unprogrammed test
• The procedure was not in conformity with the task “Fuel and Oil Leak Test” listed in the AMM. In particular, it was carried out at high thrust on all engines without the use of wheel chocks
• Testimonies and video recordings indicate that engine tests are regularly carried out without wheel chocks
• The thrust used on the engines was at the same level as the nominal braking capacity of the parking brake
• When the aircraft began to move, the ground testing technician pushed on the brake pedals and released the parking brake
• The ground testing technician turned the NWS to the right. This action, by inhibiting the CLG braking, limited the braking effectiveness
• The actions on the brake pedals were not sustained to the maximum level
• The flight testing engineer retarded the thrust levers when the plane hit the anti-blast wall
3.2 Causes of the accident
The accident is due to the run up on all 4 engines at the same time, without wheel chocks, and during which the total engine thrust was close to the parking brake capacity.
The lack of a detection process and deviation correction in the ground test procedure, in a context of industrial and commercial pressure, promoted the operation of a test outside of the established procedures.
The sudden onset of aircraft movement led the ground testing technician to focus on the braking system; therefore he did not think to reduce the thrust of the engines.
3.3 Measures taken following the accident
The Customer Acceptance Manual has been revised (May 2008) to strengthen
the instructions to follow when conducting an engine ground run. This includes:
• installing wheel chocks on all MLG wheels (and all CLG wheels if applicable)
• mandatory presence of two qualified persons at the controls during run up and taxiing.
In this same revision of the CAM, the conditions for performing engine runs at high power settings on four-engine aircraft have been modified. Such engine runs will, from now on, be performed only on two engines at a time, run symmetrically.
An internal note (EVR 473.0025/08) has been distributed to all operators of the aircraft in January 2008. This note specifies that re-tests should no longer be carried out during the same customer engine ground run (for instance for the detection of oil seepage, as happened the day of the accident). Such additional tests should be the object of a new and separate engine ground run, and not until after the problem has been reviewed at the aircraft delivery centre.
The radio communication phraseology with 'St-Martin Traffic' for the operations at Toulouse and 'Finki Tower' at Hamburg Finkenwerder has been improved, so as to assure that the engine runs will not be started until the chocks are in place: from now on, the aircraft operator will have to confirm that the chocks are in place before announcing the start of the engine runs. This modification has been introduced in June 2008 for Toulouse and in July 2008 for Hamburg Finkenwerder. It has been documented through internal notes (ME 0818073 and EVRG 473.4215/2008).
Airbus has stated that they will be creating a new document dealing with ground tests. This document, titled "Ground Operations Manual", is currently being written.
As far as training is concerned, the engine ground running "refresher course" performed on the simulator (once every two years) will be completed for each ground test technician by an internal audit carried out during a ground engine run by a "senior" technician, in order to improve the transfer of knowledge and experience. Also, the simulator session will be enhanced by the treatment and analysis of failure cases that may occur on "customer ground run" tests.
4. Safety Recommendations
The investigation highlighted repetitive deviations from the operational procedures for the conduct of ground tests, as drawn up by the direction of the ground and flight test department.
Taking into account the risk that these deviations comprise, it is necessary to guarantee that the procedures are effective and are applied, including for the other stages of the delivery.
The delivery is part of the production process supervised by EASA (European Aviation Safety Agency), and the ground and flight tests of aircraft are placed, in France, under the supervision of the CEV (Centre d’Essais en Vol).
Consequently the BEA and the BEAD-Air recommend:
• that EASA and the CEV evaluate the procedures used at the time of ground tests and of customer delivery flights, and ensure they are properly applied.
Last edited by punkalouver; 24th Feb 2009 at 00:28.