Boeing Cone Wars: Another one bites the dust

The US FAA is reporting that Boeing's fourth Boeing 787 Dreamliner prototype, dubbed ZA003, lost its fibreglass static pressure measuring device, aka "trailing cone" as it landed at Boeing Field (BFI) Friday afternoon (7 May) after a 2.5h test flight.

The device is made up of high-strength pressure tube that extends out as much as 1.5 wingspan lengths from the top trailing edge of the vertical stabilizer and is connected to a fibreglass cone at its end. The cone is there to the of the tubing to help stabilize the line, which has static ports drilled at its radius just ahead of the cone.

The unobstructed measurements of static air pressure are being used in part for reduced-vertical separation minima (RVSM) testing. ZA003, Boeing's systems test aircraft for the 787 flight test program. The aircraft is being used for noise performance, flight-deck operations, avionics, electromagnetic effects, high-intensity radio frequency response and extended twin-engine operations tests and other certification work.

"High strength" is a relative term when a device is being dragged along at airline-type takeoff and landing speeds.

BFI had cleared the pilots for a "long landing" on Runway 31L Friday afternoon at approximately 3:47pm Seattle time. Here's the audio from LiveATC.net KBFI-May-07-2010-2230Z.mp3 (scroll about halfway through to hear the action).

After landing, the pilots called the tower and reported that their "trailing cone fell off just inside the [airport] boundary". BFI then closed the runway for about 5 minutes to perform an inspection, finding the emancipated hardware located between turnoffs B5 and B7 "on the centreline".

This isn't the first time the 787 program has lost a cone. During the certification of the 747-400 Dreamlifter large cargo freighter, the aircraft that delivers 787 components to final assembly locations, the prototype aircraft (N747BC) lost is trailing cone in-flight. That time, the cone hit a car in the parking lot of a shopping centre. Damage to the car was minor; the hit to Boeing's ego, possibly, just a bit larger.