TransWorldOne is correct.

On first blush, you'd think that it is WN but, they did use them in 84'. America West never used the 727 b/c as a product of deregulation, they had not purchased them in the 727's heyday as a cutting edge aircraft the 60'2 and 70's. The last 727 non-cargo version of the 727 was in April 1983 and HP started service in Aug. 1983. While I know that they picked up planes that were built before 1983, they did not have a legacy of pilots, parts, support, etc. to for the 727 and opted for the 737, a plane still being built.

First 727 delivery:
UAL- 10/29/63
EAL- 11/15/63
AA - 1/7/64
TWA- 4/25/64
NWA- 10/12/64
PSA- 4/6/65 (US)
CO- 7/1/67
Western 10/16/69 (DL)
AK- 10/27/66

BSL