London City Has a Magnetic Personality

 - January 17, 2008, 10:13 AM

A UK Air Accidents Investigation Branch report issued this month indicates that magnetic interference at London City Airport (LCY) was responsible for “significant navigation problems” a Hawker 800XP experienced after takeoff. The incident occurred on Oct. 31, 2006, and prevented the crew from complying with the standard instrument departure while on a flight to Brussels. Fortunately, the crew was able to recover heading information 10 minutes after departure and land safely back at LCY. While stopped at holding point M at LCY, the pilots observed AHRS and HDG red flags on both primary flight displays, which the pilots described as a “known fault” at LCY due to “metal in the taxiway pilings.” When the airplane was lined up on Runway 28, the flags disappeared. However, after departure the pilots were unable to control the aircraft’s heading using the autopilot because neither of the heading selector bugs would move in response to rotation of the heading selector. The red flags reappeared, and the twinjet was subsequently radar vectored back to LCY. Investigators found that other aircraft using the airport have experienced the same phenomenon, which has been traced to magnetic interference due to the large number of steel structures underneath the airport dating back to the land’s previous use as a boat dock.