Incident at FORT MCMURRAY AB (CYMM) (Weather - precipitation, Weather - icing, ATM - NAVAIDS/radar, ATM - ILS irregularity)


2005-02-08: While conducting instrument approaches to Runway 25 at Fort McMurray, 3 aircraft reported the glide path signal in error, too high. The glide path was shut off and NOTAM action taken.
2005-03-22: UPDATE ANS and Airspace reported that warm weather with rain and then a severe drop in temperature caused approximately 10 centimeters of ice to build up in the glide path critical area. The ice build up in front of the glide path caused a shift in the glide angle. There were multiple reports to YMM FSS of the steep glide angle. Although the equipment had not failed, it was decided that the equipment should be removed from service until it could be verified. A technologist was dispatched from Edmonton to verify the condition of the ILS. When the technologist arrived on site, the ice with a layer of snow on top was discovered. The equipment monitor reflected the increase in the glide angle but was not enough to cause an alarm condition. The accumulated snow was cleared but this had negligible effect on the monitor meter readings. It was then decided to leave the equipment off until a flight check could confirm the equipment is operating within tolerance. Corrective Action: A Cat has been used to breakup the ice on the surface and clear it out of the critical area. After this work was completed the monitor readings moved closer to their nominal readings but the ground is still frozen with ice. Planned/Possible Corrective Action: A routine flight inspection was scheduled for February 14th. During the flight inspection the glide path was to be confirmed before returning the equipment to service. Interim Contingencies: The glide path was removed from service.


CADORS Number 2005C0287
Occurrence Type Incident
Reported By NAV CANADA
Occurred At 2005-02-05 - 01:27
Day or Night? Day-time
Fatalities 0
Injuries 0
Aerodrome ID CYMM
Geographic Location Alberta, Canada, North America, Prairie and Northern Region, Fort McMurray
TSB Occurrence Number
TSB Class of Investigation
AOR Number 53369-V1
Reported By NAV CANADA
Categories Wind shear or thunderstorm,Icing,ATM/CNS
Events Weather - precipitation,Weather - icing,ATM - NAVAIDS/radar,ATM - ILS irregularity

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