B737-200 crew had elevator control problems in ZJX class a airspace.

Attributes
ACN	508391
Time
Date	200103
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : diw.ndb
State Reference	NC
Altitude	msl single value : 33000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : cfi pilot : atp
Experience	flight time last 90 days : 110 flight time total : 6400 flight time type : 240
ASRS Report	508391
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical altitude deviation : overshoot altitude deviation : undershoot altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	controller : provided flight assist controller : issued new clearance flight crew : landed in emergency condition flight crew : declared emergency flight crew : diverted to another airport other
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

30 mins into cruise flight, aircraft started an uncommanded 300 FPM climb with 'a' autoplt on. We disconnected the autoplt and leveled back off. Once level again we reconnected autoplt 'B.' 20 mins later, aircraft began to climb and descend in 100-300 oscillations. We disconnected the autoplt and found the aircraft's elevator control sticking. It took a lot of pressure to lower the nose, then would unstick causing the nose to 'pop' over, then a lot of force to raise the nose, causing the same reaction in the opposite direction. Once the oscillations were under control, we found small pitch movements by hand would allow a relatively smooth flight while in a block altitude. An emergency was declared and since the aircraft was ctlable and not getting worse we diverted to atl, where we could have all the resources necessary to deliver our passenger safely to their destinations and have maintenance support to help us with our problem.

Original NASA ASRS Text

Title: B737-200 CREW HAD ELEVATOR CTL PROBS IN ZJX CLASS A AIRSPACE.

Narrative: 30 MINS INTO CRUISE FLT, ACFT STARTED AN UNCOMMANDED 300 FPM CLB WITH 'A' AUTOPLT ON. WE DISCONNECTED THE AUTOPLT AND LEVELED BACK OFF. ONCE LEVEL AGAIN WE RECONNECTED AUTOPLT 'B.' 20 MINS LATER, ACFT BEGAN TO CLB AND DSND IN 100-300 OSCILLATIONS. WE DISCONNECTED THE AUTOPLT AND FOUND THE ACFT'S ELEVATOR CTL STICKING. IT TOOK A LOT OF PRESSURE TO LOWER THE NOSE, THEN WOULD UNSTICK CAUSING THE NOSE TO 'POP' OVER, THEN A LOT OF FORCE TO RAISE THE NOSE, CAUSING THE SAME REACTION IN THE OPPOSITE DIRECTION. ONCE THE OSCILLATIONS WERE UNDER CTL, WE FOUND SMALL PITCH MOVEMENTS BY HAND WOULD ALLOW A RELATIVELY SMOOTH FLT WHILE IN A BLOCK ALT. AN EMER WAS DECLARED AND SINCE THE ACFT WAS CTLABLE AND NOT GETTING WORSE WE DIVERTED TO ATL, WHERE WE COULD HAVE ALL THE RESOURCES NECESSARY TO DELIVER OUR PAX SAFELY TO THEIR DESTS AND HAVE MAINT SUPPORT TO HELP US WITH OUR PROB.

Data retrieved from NASA's ASRS site as of July 2007 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.