B737-300 flight crew has a GS deviation during CAT 3 approach; executes a go around and returns for ...

Attributes
ACN	726220
Time
Date	200702
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : geg.airport
State Reference	WA
Altitude	agl single value : 1500
Environment
Flight Conditions	IMC
Aircraft 1
Controlling Facilities	tracon : geg.tracon tracon : mmex.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 3
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 240 flight time total : 15600 flight time type : 1500
ASRS Report	726220
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 240 flight time total : 5500 flight time type : 1600
ASRS Report	726224
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : published procedure other spatial deviation
Independent Detector	aircraft equipment other aircraft equipment : glideslope indicator other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated flight crew : executed go around
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

During CAT 3 approach into geg runway 3 our aircraft experienced a GS deviation greater than 2 dots which resulted in a manual hand flown go around and a terrain advisory by ATC tower controller. During inbound flight; conditions were normal with CAT 3 approach required by RVR 1200/1400/1400. Aircraft was configured for approach normally with exception that approach requested we fly 170 KTS to olake OM due inbound flight behind us. Prior to olake; aircraft was fully configured with both autoplts hooked up and good ILS identify. At GS intercept (approximately over olake); the captain's flight director pitch bar commanded an extreme pitch down (while first officer pitch bar remained normal) and the autoplt attempted to follow the captain's; resulting in a loss of 700 ft; GPWS pull-up advisory and controller advisory; before captain regained a positive climb and a manual go around was initiated. After go around; captain cycled frequency and automatic/manual tuner and crew decided to attempt approach again prior to divert. Second approach accomplished normally with a GS intercept speed of 133 KTS. Rollout uneventful.

Original NASA ASRS Text

Title: B737-300 FLT CREW HAS A GS DEV DURING CAT 3 APCH; EXECUTES A GAR AND RETURNS FOR LNDG.

Narrative: DURING CAT 3 APCH INTO GEG RWY 3 OUR ACFT EXPERIENCED A GS DEV GREATER THAN 2 DOTS WHICH RESULTED IN A MANUAL HAND FLOWN GAR AND A TERRAIN ADVISORY BY ATC TWR CTLR. DURING INBOUND FLT; CONDITIONS WERE NORMAL WITH CAT 3 APCH REQUIRED BY RVR 1200/1400/1400. ACFT WAS CONFIGURED FOR APCH NORMALLY WITH EXCEPTION THAT APCH REQUESTED WE FLY 170 KTS TO OLAKE OM DUE INBOUND FLT BEHIND US. PRIOR TO OLAKE; ACFT WAS FULLY CONFIGURED WITH BOTH AUTOPLTS HOOKED UP AND GOOD ILS IDENT. AT GS INTERCEPT (APPROX OVER OLAKE); THE CAPT'S FLT DIRECTOR PITCH BAR COMMANDED AN EXTREME PITCH DOWN (WHILE FO PITCH BAR REMAINED NORMAL) AND THE AUTOPLT ATTEMPTED TO FOLLOW THE CAPT'S; RESULTING IN A LOSS OF 700 FT; GPWS PULL-UP ADVISORY AND CTLR ADVISORY; BEFORE CAPT REGAINED A POSITIVE CLB AND A MANUAL GAR WAS INITIATED. AFTER GAR; CAPT CYCLED FREQ AND AUTO/MANUAL TUNER AND CREW DECIDED TO ATTEMPT APCH AGAIN PRIOR TO DIVERT. SECOND APCH ACCOMPLISHED NORMALLY WITH A GS INTERCEPT SPD OF 133 KTS. ROLLOUT UNEVENTFUL.

Data retrieved from NASA's ASRS site as of January 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.

B737-300 flight crew has a GS deviation during CAT 3 approach; executes a go around and returns for landing.