B737-700 flight crew on approach to sna encounters autoplt pitch malfunction.

Attributes
ACN	739208
Time
Date	200705
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : sna.airport
State Reference	CA
Altitude	msl single value : 2200
Environment
Weather Elements	other
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sna.tower tower : teb.tower
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 19r
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	739208
Events
Anomaly	aircraft equipment problem : less severe other anomaly
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : overrode automation flight crew : regained aircraft control
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

For some unknown reason the aircraft pitched up after GS capture into sna. We were given a heading to intercept the runway 19R ILS about 1 mi outside of the OM (lemon). The GS was 'alive' so the first officer flying called for gear down and flaps 15 degrees; which I did. The aircraft began a descent and captured the localizer. Moments later the aircraft pitched up to 13 degrees nose up and did not increase the engine thrust. I immediately added power as the airspeed rapidly decreased and the first officer disconnected the autoplt. We returned to glide path and flew the remainder of the approach manually.

Original NASA ASRS Text

Title: B737-700 FLT CREW ON APCH TO SNA ENCOUNTERS AUTOPLT PITCH MALFUNCTION.

Narrative: FOR SOME UNKNOWN REASON THE ACFT PITCHED UP AFTER GS CAPTURE INTO SNA. WE WERE GIVEN A HDG TO INTERCEPT THE RWY 19R ILS ABOUT 1 MI OUTSIDE OF THE OM (LEMON). THE GS WAS 'ALIVE' SO THE FO FLYING CALLED FOR GEAR DOWN AND FLAPS 15 DEGS; WHICH I DID. THE ACFT BEGAN A DSCNT AND CAPTURED THE LOC. MOMENTS LATER THE ACFT PITCHED UP TO 13 DEGS NOSE UP AND DID NOT INCREASE THE ENG THRUST. I IMMEDIATELY ADDED PWR AS THE AIRSPD RAPIDLY DECREASED AND THE FO DISCONNECTED THE AUTOPLT. WE RETURNED TO GLIDE PATH AND FLEW THE REMAINDER OF THE APCH MANUALLY.

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.