B757 flight crew reports being dispatched with flight deck temp control system inoperative and havin...

Narrative:

Dispatched with flight deck temp control system inoperative MEL. Shortly after takeoff; flight deck temperature uncontrollable in auto. Trim air switch to off per MEL. Flight deck and forward cabin temperature stabilized at approximately 75 degrees fahrenheit; but aft cabin temperature decreased to approximately 68 degrees fahrenheit. A call from flight attendant in the aft cabin confirmed the cold temperature reading. Trim air switch to on and flight deck temperature again uncontrollable. Trim air switch back to off and flight deck temperature stabilized but aft cabin again too cold. Trim air switch to on and flight deck temperature once again uncontrollable. After two unsuccessful attempts using trim air switch per MEL; we decided to control all compartments using the air conditioning standby mode. With left pack selector in both auto position and standby 'n' position; flight deck temperature fluctuated between 78 degrees fahrenheit (and continued increasing in auto) to 72 degrees fahrenheit (and continued decreasing in standby 'n'). Numerous adjustments between left pack selector auto and standby n were accomplished to maintain flight deck temperature. Right pack selector to standby w position stabilized aft cabin temperature to approximately 74 degrees fahrenheit. Left pack off ecias message and associated overhead light illuminated after approximately two hours of flight. Right pack switched automatically to high flow and right pack selector positioned back to auto to maintain aft cabin temperature. Right pack off ecias message and associated overhead light illuminated. Cabin altitude began to steadily increase and emergency descent from FL360 to 10;000 feet accomplished per checklist. Cabin altitude reached approximately 11;500 feet. Unable to restore left or right pack with pack off checklist. Once stabilized at 10;000 feet; we decided to turn both pack selectors to off and then auto to attempt reset. Both packs returned to normal operation. Uneventful divert and landing.

Original NASA ASRS Text

Title: B757 flight crew reports being dispatched with Flight Deck Temp Control System inoperative and having great difficulty controlling temperatures in the cabin and on the flight deck. Eventually one pack fails and the second follows one minute later; requiring an emergency descent and a diversion.

Narrative: Dispatched with Flight Deck Temp Control System inoperative MEL. Shortly after takeoff; flight deck temperature uncontrollable in auto. Trim Air Switch to off per MEL. Flight deck and forward cabin temperature stabilized at approximately 75 degrees Fahrenheit; but aft cabin temperature decreased to approximately 68 degrees Fahrenheit. A call from Flight Attendant in the aft cabin confirmed the cold temperature reading. Trim Air Switch to on and flight deck temperature again uncontrollable. Trim Air Switch back to off and flight deck temperature stabilized but aft cabin again too cold. Trim Air Switch to on and flight deck temperature once again uncontrollable. After two unsuccessful attempts using Trim Air Switch per MEL; we decided to control all compartments using the Air Conditioning Standby Mode. With Left Pack Selector in both auto position and standby 'n' position; flight deck temperature fluctuated between 78 degrees Fahrenheit (and continued increasing in auto) to 72 degrees Fahrenheit (and continued decreasing in standby 'n'). Numerous adjustments between left pack selector auto and standby n were accomplished to maintain flight deck temperature. Right Pack Selector to standby w position stabilized aft cabin temperature to approximately 74 degrees Fahrenheit. LEFT PACK OFF ECIAS message and associated overhead light illuminated after approximately two hours of flight. Right pack switched automatically to High Flow and Right Pack Selector positioned back to auto to maintain aft cabin temperature. RIGHT PACK OFF ECIAS message and associated overhead light illuminated. Cabin altitude began to steadily increase and emergency descent from FL360 to 10;000 feet accomplished per checklist. Cabin altitude reached approximately 11;500 feet. Unable to restore LEFT or RIGHT pack with PACK OFF checklist. Once stabilized at 10;000 feet; we decided to turn both pack selectors to off and then auto to attempt reset. Both packs returned to normal operation. Uneventful divert and landing.

Data retrieved from NASA's ASRS site as of July 2013 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	1015034
Time
Date	201206
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Aircraft Auto Temperature System
Person 1
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 250 Flight Crew Total 15000 Flight Crew Type 12000
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 80 Flight Crew Total 21000 Flight Crew Type 10000
Events
Anomaly	Aircraft Equipment Problem Critical

B757 flight crew reports being dispatched with flight deck temp control system inoperative and having great difficulty controlling temperatures in the cabin and on the flight deck. Eventually one pack fails and the second follows one minute later; requiring an emergency descent and a diversion.