A B737-800 crew detected a 2-3 degree difference in the trailing edge flap positions indicated on th...

Narrative:

Flap symmetry - on approach to just prior to FAF with gear down and flaps selected to 10 degrees; noticed a te split flap indication. Returned flap handle to the 5 degree position. Indications showed 7 to 8 degrees left and 10 degrees right side. No le flap transit light illuminated and no indication of asymmetry in the le devices annunciator panel. No rolling indications noticed. First officer executed the go around while I communicated with ATC initially. Once gear up and climbing out first officer handled the aircraft and ATC. I ran the checklist and made the PA's with passengers and flight attendants. Following the QRH procedures for te flap asymmetry with flaps between 1 and 15. Declared and emergency and landed on the longest runway. Airfield rescue and fire fighters called as a precaution. Landing was uneventful; taxied to the gate.

Original NASA ASRS Text

Title: A B737-800 crew detected a 2-3 degree difference in the Trailing Edge Flap positions indicated on the flap guage. No rolling was noted and no flap asymmetry warning was given. An emergency was declared and the Flap Asymmetry Checklist complied with.

Narrative: Flap symmetry - On approach to just prior to FAF with gear down and flaps selected to 10 degrees; noticed a TE split flap indication. Returned flap handle to the 5 degree position. Indications showed 7 to 8 degrees left and 10 degrees right side. No LE flap transit light illuminated and no indication of asymmetry in the LE devices annunciator panel. No rolling indications noticed. First Officer executed the go around while I communicated with ATC initially. Once gear up and climbing out First Officer handled the aircraft and ATC. I ran the checklist and made the PA's with passengers and flight attendants. Following the QRH procedures for TE flap asymmetry with flaps between 1 and 15. Declared and emergency and landed on the longest Runway. Airfield Rescue and Fire Fighters called as a precaution. Landing was uneventful; taxied to the gate.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	862872
Time
Date	200911
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Component
Aircraft Component	Trailing Edge Flap
Person 1
Function	Pilot Not Flying Captain
Person 2
Function	Pilot Flying First Officer
Events
Anomaly	Aircraft Equipment Problem Critical

A B737-800 crew detected a 2-3 degree difference in the trailing edge flap positions indicated on the flap guage. No rolling was noted and no flap asymmetry warning was given. An emergency was declared and the flap asymmetry checklist complied with.