Every recording read back from a recorder caught in a fire

The context

Sector

Research centre, Europe

Recorder

Lightweight crash-protected recorder, ED-155

Event

Impact during a test, then a battery fire

Result

Every recording read back

The recorder was on board a test vehicle. It recorded the vehicle's network data next to its own internal sensors — satellite position, rates and accelerations — and kept its memory where every crash-protected recorder keeps it: in a protected module, the part designed to survive when everything around it does not.

During a test, the vehicle struck the ground. Batteries installed nearby caught fire, and the fire was put out with water.

What the impact did

The photographs the customer sent showed the protected module on its own, its titanium cover torn off and the thermal insulation exposed. Our analysis found the cover screws sheared — something none of the tests of its qualification had produced, which points to loads outside the envelope the standard tests.

That changed the question. With the enclosure open before the fire, the protection the design counts on was no longer complete, and whether the memory had survived could not be argued from the qualification. It had to be found out, without making things worse on the way.

Before anything is powered

The first decisions were taken on site. The module was removed from the recorder and shipped to us on its own, and the customer told us how the fire had been fought: water, no foam and no powder.

That detail sets the procedure. A memory that may be wet is dried before it sees a voltage — at least 48 hours at 75 °C — because a short circuit across a damp board can destroy what the impact and the fire spared. Nothing is powered until the board has been looked at.

scroll

Opening the module

The module was opened in our laboratory the day it arrived. The memory card inside was dry, so the drying cycle was not needed, and the card was read at once.

Had the card been damaged, the next step was already planned: reading the flash chips directly, at component level, with a specialist laboratory. That route is slower, and its result is partial by nature. It was not needed.

What the memory held

Every recording on the card was read back, the test included. The customer checked the last one against their own records: the date, the start time and the duration were the ones they expected.

The end of that recording tells its own story. The vehicle's network data stops about half a minute before the end. From there, only the recorder's internal sensors keep writing, up to the impact. Those last thirty seconds exist only because the recorder carries sensors of its own.

Handing the data back

Recovered data belongs to the customer, and it can be sensitive. The customer chose to receive the test recording at once, as an encrypted download with the password sent separately, and to get the module back with an encrypted disk holding every recording and a report of what was done. Our working copy is erased once they confirm receipt.

What we take from it

Qualification says what a protected module is designed to survive. An accident can go beyond it, as this one did when the cover came off. What turned it into a full recovery was a memory that came out dry and readable, and a handling chain that added nothing to the damage: the extinguishing agent reported, the module shipped on its own, the memory inspected before anything was powered.