Warbird Information Exchange

"Over the years I've read that there are two basic stories...one is "predictable" - pilot error. Supposedly, Balfour, when someone (not sure just WHO it was) told him that they'd go over the basics of the aircraft with him, but he (reportedly), in effect said, "I've been a pilot for years and am NAA's chief test pilot, and I can figure it out for myself." Truth? Who knows. AND, as the story goes, when he was landing, he "did something wrong" with the fuel selector valve, and put it on a tank with no fuel, then the engine died during approach to Mines Field, and, upon touching down, gear down, into a soft field (of maybe strawberries!), the mains "dug-in," and it went tail over nose and wound up as we've seen it in those few photos (the only ones we've ever seen up until Paul Varga treated us to the new photos, AFAIK) of the bent-up NA-73X.
The other story is, Balfour did NOT make any errors in fuel tank selection, but that he had the nose "a little high" and the carburetor air intake, being a couple feet behind the nose of the aircraft, got "blocked" from enough incoming air and not enough air for combustion was being drawn-into the intake and (supposedly) the engine "died," and the resulting loss of power put him into the ground.
NAA, apparently, after this "untoward event," studied the problem, and as a result, down the road, the NA-73's that were getting ready to be built the same way, replete with the "short carb air intake" like the one on NA-73X, after being built with the same setup, were later modified and the intake extended to right behind the prop spinner. I've read that maybe half a dozen production NA-73's had the "short carb air intake" when they rolled off the line, but were "fixed" fairly soon (you've most-likely, see photos of the USAAF's two XP-51s both with the "short" and "long" intake, so they and the others built that way before the "long" intake became a feature of production NA-73's and follow-on Production Allison Mustangs).
When NA-73X was rebuilt, it, too, was "fixed. It's been known that NA-73X was repaired/rebuilt and flew again several months later".