Hello, Mike, thanks for the quick response.
Looking more carefully at the log book, I see Parr flew B 331 only on May 31, 1918. He was with no. 32 squadron at Beauvois. He and Alvin Andrew Callender
went "joy riding to A.S.D. to see deserter Hun D.W.F. [sic]" at St. Andre. They then flew over Le Touquet and back to Beauvois "escorting Hun and seeing the coast" (which implies that the German plane was operational.)
The plane Parr usually flew with 32 was B170, but it was having its engine replaced. Hudson lists B1-200 as SE5as, so no problem there. On June 1, he borrowed Walter Alexander Tyrrell
's B8374 (Tyrrell being on leave), but was back with B170 at the end of the day. On June 9, he started flying Sturley Philip Simpson's C9626 (which is, I presume, the plane Parr was flying when he was shot down and killed on June 10).
So: as the Germans say "lange Rede, kurzer Sinn": the other plane serial numbers are interesting, but not much help.
How do you know about B8331 being with 92 squadron? (I thought I'd looked for it without any luck at the Aircraft section of this site, but maybe I missed it. I've certainly tried all kinds of google searches to no avail.)
On a related topic: Am I missing something about navigating the list of planes at the Aircraft section? If I sort by serial number or by type of aircraft and what I want is towards the middle of the list, it takes ages to page through to that point. Yes, I can just search for "C9626" for example--but that only brings up the one plane, and I'd like to be able to see it in the context of the list. ... The list is a fabulous resource, but either it is not easy to navigate or (more likely) I'm missing a navigation tool.