How Boeing converts airplanes for cargo use

Once an airline customer decides it's more profitable for one of its passenger airplanes to carry cargo rather than people, it often turns to Boeing for a conversion. The process gives the airplane a new lease on life while creating an additional revenue stream for the carrier.

Last year, Boeing Commercial Aviation Services, which oversees a range of passenger-to-freighter and combi-to-freighter conversions for Boeing and Douglas airplane models, managed this process for 36 airplanes. CAS bases its conversion forecasts on the Current Market Outlook (CMO), evaluating the current needs of the air cargo industry and the residual value of the airplanes currently in the global fleet.

According to the Air Cargo Management Group, an aviation consulting and market research firm, freighter conversions typically take place on airplanes that are 15 to 20 years old. But ACMG said the industry-changing events of Sept. 11, 2001, led to a faster-than-normal decline in aircraft values, boosting conversion programs for relatively modern airplane types.

"In general, customers bring their airplanes to us to be converted," said Mike Stewart, Boeing vice president of Freighter Conversions for CAS, "rather than us going out and saying we want to sell them a 767 conversion." As customers are identifying their needs, he said, CAS makes determination as to whether—based on the customer input and the CMO data—it makes sense to introduce a certain model into the marketplace.

From there, Boeing works with highly experienced Maintenance, Repair & Overhaul facilities (MROs) worldwide to perform the conversions, taking advantage of their skilled workers and cost-effective labor rates. While doing the passenger-to-freighter work, these MROs also can perform heavy maintenance checks on the aircraft. On average, conversions take about two months to complete on a 737 and around four months for 747 jumbo jets.

Taking advantage of its expertise in engineering and certification, Boeing designs "low-risk" conversions using proprietary data and the latest advances in airplane technology. To do the conversions, Boeing teams with various aviation firms, including Israel Aircraft Industries. Boeing worked on DHL Worldwide Express's 34 757-200SF conversions at the Singapore Technologies Aerospace facility in Mobile, Ala. Italy-based Aeronavali has worked on DC-10s, MD-10s and MD-11s in its Venice and Naples facilities, while Taikoo (Xiamen) Aircraft Engineering (TAECO) in Xiamen, China, has modified 747-200 and -300 models. Before licensing TAECO to do this work, Boeing had performed more than 90 747 Classic conversions at its modification facilities in Wichita, Kan., and Everett, Wash.

"In the last five years or so," said Jim Edgar, Boeing Commercial Airplanes regional marketing director for cargo, "there's been a real concern among regulatory agencies for the underlying credibility and the engineering expertise that went into the modifications." Because CAS works with the airplane's original design, these conversions are "way less subject to recall down the road if problems arise. Who better to start cutting it up than the people who made the airplane?"

Here's how a Boeing passenger airplane becomes a shipper of freight:

• Most significant is the installation of a side cargo door, as well as reinforcement and/or replacement of the main deck floor beams to accommodate higher running loads. While cargo door sizes vary, all are sized to accommodate industry standard pallets and containers on both narrowbody and widebody freighters.

• After floor beams are reinforced or replaced as necessary, the former seat tracks are modified to accept a cargo-handling system.

• A restraint (which could be a net or a rigid barrier) and a smoke barrier are installed at the front of the airplane to protect the flight crew.

• The smoke detection and fire suppression systems are modified to the latest certification requirements.

• The environmental control system is modified in order to maintain a constant—and sometimes controllable—temperature in the main-deck cargo compartment.

• Flight deck systems are modified, and changes also are made to the flight deck windows of some models to provide the flight crew an alternate emergency exit path.

• Electrical, hydraulic and flight control systems also may require modification because of the major structural changes a conversion requires. In some cases, landing gear reinforcements also are performed.

Freighter conversions comprise about two thirds of the world's current cargo fleet, Stewart said, and forecasts predict that this number will rise. This gives Boeing a chance to support its customers further with packages including avionics and flight deck upgrades, and integration of technical manuals.

Since "that airplane is going into a new fleet, that customer wants to standardize things on that aircraft," Stewart said. "A lot of the value in working with Boeing is the ability for customers to package a lot of other work together.

"And the customer knows, if it's a Boeing upgrade performed by Boeing engineers, it's the same quality they can expect in a new airplane."

—Maureen Jenkins