N501PJ

This airframe, registered as N501PJ, is a 1979-built Cessna 501 Citation I/SP with serial number 501-0111. It is owned by the corporation DIAMOND K ENTERPRISES INC, based in Caldwell, TX, US, and has been operated from that location as its principal base. The airframe is a U.S.-registered, single-pilot certified executive jet that retains a documented valuation of $550,000 and is characterized by long-term private/corporate ownership rather than active commercial charter use. Ownership continuity under DIAMOND K ENTERPRISES INC is the primary notable registry condition in the available record.

The cabin in this airframe is an executive-style 6-place layout with club and forward seating and a belted aft lavatory consistent with the single-pilot certified ISP configuration; the aircraft is certificated for a total of 8 seats including the flight crew. Avionics installed on this airframe include Garmin 500 WAAS (TAWS/GPSS), Avidyne EX-500, SPZ-500 autopilot, Garmin transponders, Avidyne TAS-620 traffic, and Collins NAV/COM/DME, providing a mixed analogue/digital fit suitable for regional business missions. Typical operations for this airframe type and configuration include short- to medium-range executive transport and owner-flown cross-country flights within the U.S., leveraging a cruise speed of 357 kts and a maximum practical ceiling of 41,000 ft. Maintenance considerations for this specific jet focus on older JT15D engine support and avionics integration upkeep for continued single-pilot certified operations.

The Cessna 501 Citation I/SP occupies the light business jet niche as an early-generation Citation optimized for owner-operators and corporate single-pilot use. With its twin Pratt & Whitney Canada JT15D-1A powerplants and a range of 1,328 nm, it competes historically with other light jets of the late 1970s and 1980s era in private and corporate markets. Buyer and charter demand for this airframe typically centers on cost-conscious owners seeking proven, simple systems rather than modern glass-cockpit amenities; consequently resale values and market liquidity reflect airframe age and retrofit status, as indicated by the listed valuation of $550,000. Maintenance and parts support considerations can affect operating economics given the vintage engines and mixed avionics fit.