Three years and four months time has passed since the A400M accident, one of the events which for sure is recalled by any aviation enthusiast. Even more by the Spanish ones or by those related to Airbus, the European aircraft manufacturing company. And not precisely because of being something good and worth remembering, quite the opposite.
9th May 2015 at Seville – San Pablo Airport (Spain), It is Saturday 12:05 AM and the A400M named MSN023 (Manufacturer’s Serial Number) was about to take off for the first time to perform some in-flight tests. Nobody could predict what was going to happen next.
Just after around three minutes on air, an unexpected failure left three out of the four engines powerless and without recovery capacity. In light of this dramatic situation, the only option was to perform an emergency landing so the aircrew reported the emergency and ask for returning to the airport straight away.
Thanks to the recently released images published by Europapress, and the first-person testimony of the photographer, Manuel Vilela, more details about the last stages before the final impact have been revealed.
Once declared the emergency, a too abrupt roll to the left in order to return to the departure airport unstabilised the aircraft. Right after, and being the aircraft falling uncontrollably down, the return to the airport turned out impossible at that time.
Avoiding the industrial and commercial facilities around the airport, the only available landing area nearby was some farming fields in which Manuel Vilela was taking photographs that morning. The maneuver was proved impossible due to the aircraft imbalance and the lost of engines thrust. In addition to that, the surrounding airspace was crossed by uncountable overhead power lines, making even more lethal the aircraft path.
When collided to the ground, the aircraft was rolled around 30 degrees to the left. The first impacting part was the left wing bursting into a fireball, followed by a second fireball when the right wing hit the ground. Simultaneously, the cabin broke in two halves spitting out all the items inside.
Next, and while the damaged aircraft expelled rests of its structure and pieces of equipment, the T-shaped tail hit one of the above-mentioned overhead power lines provoking the third big explosion. In a matter of seconds and with no chance to react, all was in flames, one of the power lines’ pylons knocked down, and several explosions of lower intensity kept happening.
Manuel Vilela, the photographer and first-person witness of the accident, called Emergencies who after a few minutes get there and began to assist the crew members. Moreover, and exercising a strong sense of responsibility, Manuel Vilela proceeded to deliver all his photography material straight away to the competent judicial authority for helping in the further investigations.
The fatal outcome of this terrible event were four casualties out of six crew members: Captain, Jaime de Gandarillas; First Officer, Manuel Regueiro; and Engineers, Gabriel García Prieto and Jesualdo Martínez. The other crew members; José Luis de Augusto Gil, and Joaquín Muñoz de Anaya; resulted badly injured and still suffering the effects of the accident.
The Commission for the Technical Investigation of Military Aircraft Accidents (CITAAM), dependent on the Spanish Defence Ministry, was the entity in charge of the experts’ technical report elaboration about the A400M accident.
The main conclusion of this report was that the accident was eventually caused by a software failure: the incorrect loading of this software on the engines’ Electric Control Units (ECU) erased some critical parameters for the engines to operate correctly in flight. This issue kept unnoticed till was triggered in mid-flight.
MSN023 was the second A400M flying with the new engines’ software developed by Europrop International (EPI ), which was responsible for loading the software into the Electric Control Units (ECU) of the engines, even if there was an update to be made in the Airbus factory. However, with a new software release, the loads began to be made by Airbus, which understood that the software could be used ‘freely’ and ‘within the use limitations established by the manufacturer’, a position that was not shared by EPI.
In this particular case the engines arrived the factory with an old software release but, before the delivery, a new release obtained the certification. Airbus wanted to update it before the delivery to the Turkish Air Force, but in the ‘absence of an agreed procedure’ for loading the software, EPI informed Airbus that it could not sign this ‘supplementary’ certification. As a result, EPI staff went to the factory in February 2015 to load the new software release in several aircraft, one of them the MSN023.
Above procedure was registered in the engine logbook, being stored by EPI, but not in a yellow card which includes, among other data, the engine ECU version. The report states that there is no record of yellow cards delivered by Airbus to EPI for updating. This fact caused that Airbus checked the engine software to load the new release just a month after EPI successful loading.
During the Airbus check, the new software release was not detected proceeding then to load it into the ECU. Furthermore, the aircraft electrical configuration for the loading process was not correctly collected in the work order, leading to a wrong energizing of the ECU and some loading errors.
The software loading was eventually performed, but by then the torques calibration parameters of one of the channels had been already erased. Despite the loading errors, those were not collected in a nonconformity sheet or officially reported and, besides, the torques calibration parameters were not verified after the software loading. Both actions should have been performed as stated procedures.
At this point, the operational logic of the ECU allowed a normal engine on-ground operation, nevertheless, and due to the lack of parameters in one of the channels, the system did not know how to act in-flight leaving the engines in idle. This failure, included in the document called ‘problem report’, was considered far remote enough to happen that was accepted to be corrected in the next software release.
One of the ECU was changed by another one before the flight, which already had the software well updated, and that was the reason for the only engine working as expected.
In conclusion, the report states the lack of coordination between EPI and Airbus regarding the software uploading and update processes, and that Airbus did not agree with EPI its software charging procedure.
The main conclusion in this sense was that the crew took reasonable decisions in the light of the arising issues suffered in-flight, even though they were not the most adequate.
Despite the errors in the crew performance, they acted in a logical way according to the warnings and alerts received, the operational limitations imposed by the control tower, and the lack of training of the crew concerning the arisen emergencies.
The three engines failure at the same time is so unlikely, and with such critical effects, that it was really difficult to process all the information available in the cockpit to take the appropriate decisions in such a short period of time.
The accident and its consequences were investigated by the court of instruction number 13 of Seville. The last step took place the last 3rd April 2018 and it was the stay (dismissal without prejudice) of the case ordered by the head of the court María José Moreno. Considering that there were no indications to continue the criminal prosecution and after the Prosecutor’s Office request.
Likewise, the request for additional investigation presented by the private prosecutions, including the ones of the crew members’ families, was rejected.
The court pointed out that the accident was caused by a ‘concatenated set of events’, but none of them with ‘enough’ entity to attribute criminal liabilities. However, it was also stated that “multiple failures” were made by Airbus and Europe International (EPI).
This decision was appealed by the majority of the prosecutions to revoke it and to keep open the procedures, requesting as well the opening of new ones ‘needed’ for ‘the total clarification’ of the facts. This appeal was dismissed by the court, but at this time this order for dismissal has been appealed too at the Provincial Court of Seville. It will have to decide among the definitive dismissal of the proceedings or to continue with them and the opening of the new ones requested by the prosecutions.
The accident investigation reveals some things that sound self-evident, but worth to recall from time to time: define and follow rigorously stated procedures when developing engineering works is a must, as well as register and report whichever arising issue during their performance. No matter how relevant or important they seem to be because the incidents and accidents are mainly caused by the addition of minor issues or mistakes.
The only positive side of such dramatic events is that their investigations allow reducing the risks and the probability of happening again.