Air crash investigators risk being sidelined in a tussle to unlock the secrets of lost flight MH370, fuelling concerns that their role in making flying safer could be diminished.
By drifting on to Reunion Island, the barnacled remains of a Boeing wing part from the Malaysia Airlines jet have given the upper hand to a French judicial investigation, exposing for the second time this year how civil crash investigations struggle to compete with police-led probes.
For decades, reconstructions of disasters by specialist safety investigators have been seen as crucial to making aviation safer, with accident rates at historically low levels.
But in dozens of countries, notably France, they exist in uneasy co-habitation with separate criminal inquiries.
Simmering tensions over the sharing of evidence between civil and judicial investigators came into the open after the crash of a Germanwings jet into the French Alps in March.
They are under scrutiny again after Indian Ocean currents deposited the “flaperon” from the missing Malaysia Airlines flight into the hands of judges investigating the suspected manslaughter of four French citizens out of 239 people on board.
How France handles both cases could have a wider impact given its influence over aviation safety worldwide and the similarity between its civil-law system and most other jurisdictions.
Supporters of the French system of parallel investigations say it prevents cover-ups, supports families and benefits from stronger powers of discovery.
Concerns about judicial interference may cut little ice with MH370 families who have been frustrated at the apparent lack of results from the civil investigation into the disappearance of the Kuala Lumpur to Beijing flight.
“This kind of closed, unjust, and totally inefficient investigation is really hard for me to understand,” said Jiang Hui, a Chinese man whose mother was aboard Flight MH370.
While families wait for clues about the missing jet, 17 months after MH370 mysteriously vanished, the flaperon risks being submerged once again by jurisdictional in-fighting.
Malaysia played down any conflict between the judicial probe and its own civil investigation.
But experts say it is a further setback for the Southeast Asian nation which struggled to establish an independent investigation in the face of criticism.
The debate about the blurring of judicial and civil roles could complicate efforts to improve safety by openly discussing problems in everyday operations.