Max Kingsley-Jones/Paris

As the world's air forces increasingly focus on the private sector to provide support services such as airlift and training, Omega Air and its partners are rising to the challenge by offering air- refuelling tankers on a lease-by-the-hour service.

Omega, based in Dublin, Ireland, is a Boeing 707 leasing specialist. It leads the five-member consortium Team Inflight Refueling (IFR), which has developed a conversion team for the 707. Flight-testing of the first aircraft is soon to begin, and Omega expects to sign the Canadian Forces as the launch customer.

Team IFR partners include Tracor Flight Systems (responsible for aircraft modification and certification), Derlan (responsible for system integration/programme management), Able (responsible for hose-reel units (HRUs) and aerial-refuelling pumps) and West Coast Netting (responsible for the hose and drogue).

Omega, which has a fleet of more than 25 707s, has conceived the tanker conversion so that it does not impinge on the aircraft's capability in the freighter or passenger-carrying role. The IFR conversion is priced at around $6 million, and is suitable for installation on other aircraft types. The tanker modification is a two-stage process, with the first ("A" kit) involving the installation of the permanent items such as plumbing, electrics, camera system and fuel pumps. This work requires around 30 days downtime and is being undertaken by Tracor at its Mojave, California, plant.

The "B" kit, designed for quick installation/removal, includes two palletised HRUs and hydraulic pumps, and the flight engineer's cockpit control panel, with the whole package weighing just over 400kg. The HRUs, which are controlled by a microprocessor system developed by Able, are installed side by side in the rear cargo hold. The B kit can be transferred between aircraft within 2h, claims Omega.

Kevin O'Neill, Omega's quality manager, explains that the dual centreline HRU design provides single-point hose-and-drogue refuelling. "Only one HRU will be deployed at a time, and the second HRU provides immediate redundancy should the first system fail," he says. The system is operated by the flight engineer from a control panel at the side of his systems station, although most of the operation is controlled automatically.

 

Fuel-flow rates

"The system will normally provide a fuel-flow rate of 350USgal [1,330litres]/min using a single pump, with flow automatically regulated to match the receiver aircraft's ability to accept the fuel," explains O'Neill. "For larger aircraft, we can use two pumps, which enables flow rates of 520US gal/min," he adds. Although O'Neill considers that the 707-320's standard fuel capacity (90,650litres) is adequate, he confirms that Omega is looking at auxiliary-fuel options.

Modification of the first aircraft, a 707-320B, is complete, and this aircraft was displayed at the Paris air show in June. O'Neill says that flight testing will begin by August. "Actual refuelling testing will be undertaken from Mojave, using Tracor's own McDonnell Douglas F-4s, and later with the US Navy at Patuxent River," he says. He adds that Omega expects to receive its US Federal Aviation Administration supplemental type certificate (STC) by September. "Omega will hold the STC, and has exclusive marketing rights for the first ten years," he says.

O'Neill says that Omega will offer the tanker on "power-by-the-hour"-type lease contracts to air forces requiring additional tanking capacity. "We expect to have signed up the Canadians by the end of the year, which has a requirement for two aircraft," he says, adding that interest has also been shown by the US Navy (for six aircraft) and Brazil.

Meanwhile, Omega has developed a Pratt & Whitney JT8D-200 re-engineing programme for the 707, which it is to begin test-flying in August 1998. The company has signed an agreement with P&W for the re-engineing and has formed a US-based partnership, "7Q7", which plans to certificate the JT8D-powered version in April 1999.

According to Ulick McEvaddy, a director of Omega and a vice-president at 7Q7, the company plans to retrofit its 707 fleet over the next ten years, and is in discussion with other 707 operators. McEvaddy says that the conversion will cost around $15-16 million per aircraft.

The 707-320's four noisy and inefficient 80kN (18,000lb)-thrust P&W JT3Ds will be replaced by 97kN JT8D-219s, which power the McDonnell Douglas MD-80. The new powerplant offers a 45kg weight saving per engine and will provide a 20% reduction in fuel consumption and Stage 3 noise compliance, with a considerable margin at the 707's maximum take-off weight of 152,500kg. The modified 707 should offer up to 30% more range, and be some 50% faster in time to climb to 37,000ft (11,300m).

Source: Flight International