That’s from Captain Simpson’s first written statement, recording his recollections of his initial interview with Chippindale. A copy is at pages 352 and 353 of MacFarlane’s book. The relevant passage is as follows:
“Did Captain Collins contact you after your flight, or didyou discuss your flight with him?”
“No. but I did telephone Captain Johnson … with the suggestion that maybe it would be a good idea to point out to future crews that on Antarctic flights the McMurdo position on the flight plan was to the west of the McMurdo TACAN coordinates, so they would carefully consider any cross-track errors before rushing into a manual update over the McMurdo base area. Although I had been expecting to go the left of the Nav track when flying visually on heading to track over the airfield area, I had been somewhat surprised to see it was as much as 28 miles left when over the TACAN.”
All consistent with a belief that the waypoint was at the NDB at McMurdo Station, which was a short distance to the west of the TACAN - so Captain Simpson expected to be left of track when over the TACAN, but not by much. If megan is correct, that that assumes any of these questions have ever crossed that young mind, there would have been nothing to be “somewhat surprised” about.