B737NG suffers pitch anomaly on GS to runway 16R at sea. Reporter suspects GS transmitter problem.

Attributes
ACN	814988
Time
Date	200812
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	msl single value : 2700
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 16r
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 180 flight time type : 4000
ASRS Report	814988
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : overcame equipment problem flight crew : overrode automation
Supplementary
Problem Areas	ATC Facility Aircraft
Primary Problem	ATC Facility

Narrative:

Flying approach from glasr arrival on vectors to final. Descended on GS to about 2800 ft. Just broke out below the ceiling and airplane autopilot pitched from around 5 degrees nose up to 2 degrees nose down. I disconnected the autopilot; corrected pitch and continued flying. GS transmitter for sea runway 16R is suspect.

Original NASA ASRS Text

Title: B737NG suffers pitch anomaly on GS to Runway 16R at SEA. Reporter suspects GS transmitter problem.

Narrative: Flying approach from GLASR arrival on vectors to final. Descended on GS to about 2800 ft. Just broke out below the ceiling and airplane autopilot pitched from around 5 degrees nose up to 2 degrees nose down. I disconnected the autopilot; corrected pitch and continued flying. GS transmitter for SEA Runway 16R is suspect.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.