NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Magnetic anomaly incident at London City Airport
From: Paul Hirose
Date: 2008 Jan 25, 20:23 -0800
From: Paul Hirose
Date: 2008 Jan 25, 20:23 -0800
The UK Air Accidents Investigation Branch recently released a bulletin on the airplane that returned to London City Airport shortly after takeoff due to large discrepancies on its heading displays. There's a history of heading system troubles observed by crews after takeoff here. In addition, planes often wander off the correct departure course for no apparent reason. Investigators found a powerful magnetic anomaly on a taxiway. It's supported on pilings made from sections of a former oil pipeline. In addition, the area used to be a dock. Massive bases for the old cast iron bollards are still under the ground. All this underground metal generates a disturbance powerful enough to drive a gyro stabilized magnetic compass system tens of degrees from the correct heading, if a plane waits there for a few minutes. The AAIB report mentions similar troubles at other airports. For example, at Houston, Texas, a runway became magnetized by a cleaning process which blasted the pavement with steel shot. Planes experienced heading anomalies of 40 to 90 degrees. With a combination of degaussing (not completely successful), pilot awareness, and the passage of time, the problem faded away. http://www.aaib.gov.uk/publications/bulletins/january_2008/raytheon_hawker_800xp__cs_drq.cfm -- I block messages that contain attachments or HTML. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---