While the USAAC could block any sales it considered detrimental to the interests of the US, the NA-73 was considered to be a special case because it had been designed at the behest of the British and all dealings were directly between the BPC and NAA, and did not involve the US Army or Wright Field in any way. In September 1940, a further 300 NA-73s were ordered by the MAP. To ensure uninterrupted delivery, Colonel Oliver P. Echols arranged with the Anglo-French Purchasing Commission to deliver the aircraft and NAA gave two examples (41-038 and 41-039) to the USAAC for evaluation."P-51 History: Mustang I." The Gathering of Mustangs & Legends. Retrieved: 26 March 2009.
While the USAAC could block any sales it considered detrimental to the interests of the US, the NA-73 was considered to be a special case because it had been designed at the behest of the British and all dealings were directly between the BPC and NAA, and did not involve the US Army or Wright Field in any way. In September 1940, a further 300 NA-73s were ordered by the MAP. To ensure uninterrupted delivery, Colonel Oliver P. Echols arranged with the Anglo-French Purchasing Commission to deliver the aircraft and NAA gave two examples (41-038 and 41-039) to the USAAC for evaluation."P-51 History: Mustang I." The Gathering of Mustangs & Legends. Retrieved: 26 March 2009.