French investigators are seeking assistance to locate engine parts which they believe fell from an Airbus A220-300 as it passed over the east of the country last month.
The Swiss aircraft had been operating the LX348 service to London Heathrow from Geneva on 25 July.
While climbing through 32,000ft the aircraft suffered a mechanical failure of its left-hand Pratt & Whitney PW1500G engine.
The crew shut down the powerplant, says French investigation authority BEA, and diverted to Paris Charles de Gaulle.
Inspection of the aircraft subsequently determined that the stage one rotor of its low-pressure compressor was missing.
US investigators have taken the lead on the inquiry.
But BEA is putting out a public call for witnesses in an effort to find missing parts of the engine which, it say, may have fallen into a forest area near Perrigny-sur-Armancon, some 190km south-east of Paris.
It has identified the geographical co-ordinates defining an oblong primary search region.
BEA states that the missing compressor parts are made of titanium and no longer than about 30cm. It warns that the parts could be "very sharp" and should be handled with care, and that anyone finding suspect debris ought to note its location and email a photograph of the item to BEA for further instructions.
None of the occupants of the aircraft (HB-JCM) was injured. Cirium's Fleets Analyzer shows the aircraft was only delivered at the end of May last year.