MD80 crew found the right pack mixing valve was stuck in the cold position.

Attributes
ACN	556386
Time
Date	200208
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : lgb.airport
State Reference	CA
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	556386
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : pack mixing valve position indicator. pack temp. other flight crewa other flight crewb
Resolutory Action	aircraft : equipment problem dissipated other
Consequence	other other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

After departure from lgb, we discovered that the right temperature controller was stuck in the full cold position and would not work in either automatic or manual. After looking in both books and finding no procedure, we called maintenance to troubleshoot. They recommended pulling and resetting 3 circuit breakers. We tried this to no avail, and found with our heavy passenger load and keeping the left controller hotter than normal, it was bearable in the aft part of the jet. After leveling at cruise, I decided to turn on all the wing and engine anti-ice to see if this would do any good. Almost as soon as the wing anti-ice came on, the valve started working, leading me to believe that the pressure change unstuck the control valve. I think it would be a good idea to incorporate this procedure with the circuit breakers and anti-ice into our QRH book. Since it was a balmy morning in lgb, the valve, being in the full cold, worked for our cooling needs on the ground, so we never knew it wasn't working properly. Had it been a cold/frosty morning in winter with a valve stuck in the 1/2 - 3/4 position, we may have had to divert shortly after takeoff for an uncontrollable cabin temperature.

Original NASA ASRS Text

Title: MD80 CREW FOUND THE R PACK MIXING VALVE WAS STUCK IN THE COLD POS.

Narrative: AFTER DEP FROM LGB, WE DISCOVERED THAT THE R TEMP CONTROLLER WAS STUCK IN THE FULL COLD POS AND WOULD NOT WORK IN EITHER AUTO OR MANUAL. AFTER LOOKING IN BOTH BOOKS AND FINDING NO PROC, WE CALLED MAINT TO TROUBLESHOOT. THEY RECOMMENDED PULLING AND RESETTING 3 CIRCUIT BREAKERS. WE TRIED THIS TO NO AVAIL, AND FOUND WITH OUR HVY PAX LOAD AND KEEPING THE L CONTROLLER HOTTER THAN NORMAL, IT WAS BEARABLE IN THE AFT PART OF THE JET. AFTER LEVELING AT CRUISE, I DECIDED TO TURN ON ALL THE WING AND ENG ANTI-ICE TO SEE IF THIS WOULD DO ANY GOOD. ALMOST AS SOON AS THE WING ANTI-ICE CAME ON, THE VALVE STARTED WORKING, LEADING ME TO BELIEVE THAT THE PRESSURE CHANGE UNSTUCK THE CTL VALVE. I THINK IT WOULD BE A GOOD IDEA TO INCORPORATE THIS PROC WITH THE CIRCUIT BREAKERS AND ANTI-ICE INTO OUR QRH BOOK. SINCE IT WAS A BALMY MORNING IN LGB, THE VALVE, BEING IN THE FULL COLD, WORKED FOR OUR COOLING NEEDS ON THE GND, SO WE NEVER KNEW IT WASN'T WORKING PROPERLY. HAD IT BEEN A COLD/FROSTY MORNING IN WINTER WITH A VALVE STUCK IN THE 1/2 - 3/4 POS, WE MAY HAVE HAD TO DIVERT SHORTLY AFTER TKOF FOR AN UNCTLABLE CABIN TEMP.

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.