156 Squadron Mission Details
Target: Gennevilliers
Mission Date: 29/04/1942
Mission Comments: Six aircraft were employed on operations from which F/O PINION and crew failed to return and were posted as Missing
Rego Type Captain Departed Over Target Height Returned Flight Time Comments ORB Slide
X3742  Wellington  P/O SMITH  21:10  .14  8000  02:50      020 
Z1571  Wellington III  F/O PINION  21:13          T/o 2113 Alconbury. Crashed at Bievres (Seine-et-Oise), 12 km SE of Versailles. All rest in Bievres Communal Cemetery.

New information from a WWII Researcher (Jerome LeBlanc):
The crash site of Wellington III Z1571 GT 29-30th April 1942 is not the city Bièvres (Essonnes - 91) where the crew was buried.

The crash site is the city of Gennevilliers.
Gennevilliers was the target.
The services of the files of the town of Bièvres and Gennevilliers confirm this fact.
The German military authorities of the airfield of Villacoublay were charged to bring back the bodies of the aviators on the airfield of Villacoublay.
When the bodies were brought back to Villacoublay, the Germans decided to bury the bodies in the cemeteries of Bièvres. 
X3741  Wellington  Sgt. POTTS  21:15  23.55  20000  02:20      020 
X3706  Wellington III  F/Lt MACLACHLAN  21:15  .01  5000  03:00      020 
X3677  Wellington  P/O BAIN  21:20  .25  6000  02:30      020 
X3710  Wellington III  F/Lt SHILLETO  21:20  .02  3000  02:40    THOMPSON is not mentioned in a rather crowded entry in the ORB. As he was a normal member of the crew I have added him in. [ED]  020