The Double Sunrise pioneers

The RAF supplied five Catalinas to QEA via BOAC from aircraft received under Lend-Lease allocations. They were modified for civil use by BOAC with some work for the last three aircraft performed at Rose Bay. The first two aircraft received by BOAC in October 1942 had already operated on the airline’s African and Mediterranean routes, were followed by two aircraft in July 1943 and the last in April 1944. In QEA service they retained RAF camouflage and serials, British civil registrations with an additional identifying white fleet number appearing on the lower tail, now named by Crowther after stars QEA used in celestial navigation. The QEA number, registration, names and type were: 1 G-AGFL Vega Star PBY-5B; 2 G-AGFM Altair Star PBY-5B; 3 G-AGID Rigel Star PBY-5; 4 G-AGIE Antares Star PBY-5; and 5 G-AGKS Spica Star PB2B-1.

On June 29 1943 QEA Captain Russell Tapp, accompanying the RAF crew who ferried the aircraft on its delivery flight, conducted the first Indian Ocean Air Mail flight from Perth to Koggala Lake, with G-AGFM, the aircraft overloaded at an AUW of 35,150lb. The first weekly regular service, Flight 1Q1, with Tapp, and Crowther as navigator, departed Koggala Lake on July 10 1943, with G-AGFM at a 34,800lb AUW on the planned 3,444nm flight. Flight time was 28hr 9min with 400gal of fuel remaining. Payload on flights was restricted to 1,000lb carrying a maximum three passengers.

A long-range economical cruise plan was devised, at a constant 2,000ft cruising altitude, divided into five hour segments, each segment covering 574nm at a constant 115kt cruise during the entire flight. Power was progressively reduced as the aircraft lightened through fuel consumption. For example during each of the first five hours, power was set at 2,100rpm delivering 620hp at 75gal/hr, and after 25 hours into the journey, each of those hours at 1,800rpm delivering 500hp at 55gal/hr. Takeoff times varied from 50sec into a 15kt headwind to 115sec on a calm glassy surface. The Catalina’s normal fuel capacity of 1,457.6 Imperial gal (6,626.4L) was increased to 1,980 gal (9001L) with additional belly tanks and all unnecessary items such as armour plating and deicing equipment removed to reduce weight.

The journey was conducted in radio silence except for a period at the beginning and end of the flight. On occasion, unscheduled alightings were made in sheltered waters. To cope with emergencies 120gal/min fuel dump valves were fitted and sometimes engaged. Most flights were direct with deviations at times to Cocos Islands for operational reasons, a location generally avoided because of potential enemy activity. With experience, the additional fuel tanks were relocated to improve flying characteristics. By Qantas engine operational calculations, the seven tons of fuel carried could provide an absolute 4,650 miles and 36 hours endurance. The flight times generally ranged between 27 and 32 hours giving passengers the pleasure of receiving their treasured “Secret Order of the Double Sunrise” certificates signed by the captain. When the service concluded in July 1945, 271 flights had been conducted carrying 858 passengers, 207,260lb (94,012kg) of mail and 90,793lb (41,183kg) of war priority freight.

One problem encountered were delays faced by arriving passengers from Koggala Bay waiting in Colombo for a seat on connecting BOAC flights to London. BOAC asked QEA if they would operate an extension to Karachi using the RAF base there at Korangi Creek using BOAC facilities. The first flight operated by Altair Star on November 4 arrived at Karachi after a 12hr 30min flight and the return Karachi-Perth flight over 4,970 miles took 41hr 40min via Koggala Lake, imposing considerable strain on the Qantas crews. The Catalinas from Perth were timed to arrive at Koggala Lake in the early morning, were serviced and departed at night for a 0700 Karachi arrival the following morning.

In 1949 Captains L R Ambrose, W H Crowther and R B Tapp of Qantas, were awarded the Johnston Memorial Trophy of the Honourable Company of Air Pilots incorporating Air Navigators in recognition of the navigational skills demonstrated on the flights. They joined some other notable recipients of this trophy: Squadron Leader Herbert Hinkler, J A Mollison, Jean Batten and Captain P G Taylor (three times).

Under Lend-Lease terms, the Double Sunrise Catalinas were disposed of and scuttled after the war with Altair Star, Antares Star, Rigel Star and Vega Star off Rottnest Island, and Spica Star off Sydney Heads, in early 1946. A reminder of the epic flights is displayed at the Qantas Founders Museum, Longreach, with their Catalina exhibit resplendent as Antares Star.

‘Armour plating and de-icing equipment was removed to reduce weight.’