This article was written by Bryan R. Swopes and first published on This Day in Aviation. Read the original article here.

On May 1–3, 1976, Pan American World Airways’ Boeing 747SP-21 “Clipper Liberty Bell” (N533PA) departed New York’s John F. Kennedy International Airport (JFK), on a record-setting flight around the world. The flight set a new speed record for a flight around the world, eastbound, and three speed records for commercial airline routes.

Under the command of Captain Walter H. Mullikan, the airline’s chief pilot, the Clipper Liberty Bell’s flight crew included co-pilots Albert A. Frink, Lyman G. Watt, and flight engineers Frank Cassaniti and Edwards Shields. The airliner carried 98 passengers.

Clipper Liberty Bell flew eastward from New York’s JFK Airport to Indira Ghandi International Airport (DEL) in New Delhi, India, a distance of 8,081 miles (13,005.1 km), at an average speed of 540.363 mph (869.63 kph).

After servicing the 747, it continued on its journey. The next destination was Tokyo International Airport (HND) in Tokyo, Japan. This stage covered 7,539 miles (12,132.8 km). The airliner’s average speed was 261.722 mph (421.20 kph).

After refueling, the Pan American flight continued on to its starting point to New York’s JFK Airport. This final leg was 7,517 miles (12,097.4 km). The average speed was 567.001 mph (912.50 kph).

The total duration of the flight was 46 hours, 1 second. The actual flight time was 39 hours, 25 minutes and 53 seconds. Total distance flown was 23,137 miles (37,235.4 km). The average speed for the entire flight was 502.838 mph (809.24 kph).

Boeing 747SP-21 N40135, c/n 21025, 1 January 1975. (

The Boeing 747SP (Special Performance) is a very long range variant of the 747-100 series airliners. It has a shorter fuselage and larger tail surface than the standard model. The weight savings allows it to carry more fuel for longer flights, and it is also faster. Boeing built 45 of these 747SPs.

The 747SP is 184 ft, 9 in (56.312 m) long, with a wingspan of 195 ft, 8 in (59.639 m). It has an overall height of 65 ft, 10 in (20.066 m). Its maximum takeoff weight is 670,000 lbs.

The airliner has a cruising speed of 0.88 Mach (616 mph or 991 kph) and a maximum speed of 0.92 Mach (680 knots, 1,094 kph). The service ceiling is 45,100 ft (13,746 m) and the range is 7,650 miles (12,311 km), carrying 276 passengers and baggage. Its fuel capacity is 47,210 gallons (178,709 liters).

The record-setting Boeing 747SP-21, serial number 21025, was the fourth Special Performance 747 built, and one of 10 that had been ordered by Pan American World Airways. It was powered by four Pratt & Whitney JT9D engines.

It first flew on October 8, 1975, in Boeing’s corporate paint scheme. It was retained for use in the test fleet. When testing was completed the airliner was refurbished and repainted in the Pan Am livery. It was delivered to the airline on March 5, 1976, and registered as N533PA.

Pan Am Boeing 747SP-21, Clipper Young America, N533PA, c/n 21025, circa 1985. (

In 1977, Captain Mullikin flew the same 747SP on another circumnavigation, but this time it crossed both the North and South Poles. Renamed as “Clipper New Horizons”, the 21025 set a record on that flight as well, with a total flight time of 54 hours, 7 minutes, 12 seconds. While in the Pan Am fleet, the N533PA also carried the names “Clipper Young America” and “Clipper San Francisco”.

Pan American sold its fleet of Boeing 747SPs to United Airlines in 1986. The 21025 was re-registered as N143UA to reflect its new ownership. After twenty years, the 21025 was removed from service in 1995 and placed in storage at Ardmore, Oklahoma, U.S. It was scrapped in December 1997. The airliner had accumulated 78,941 total flight hours on its airframe (TTAF) with 10,733 cycles.