Unable to pressurize their B757 after takeoff from ord, flight crew declares emergency and returns t...

Attributes
ACN	622146
Time
Date	200406
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 23000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
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
ASRS Report	622146
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : diff. pressure indicator other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : landed as precaution flight crew : diverted to another airport flight crew : landed in emergency condition other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance Environmental Factor
Primary Problem	Aircraft

Narrative:

On climb out, we noticed no airflow into the cockpit (gaspers or overhead). All indications were normal. Loud rumble was heard below captain's kit bag area for a few mins on climb out. Looking into the problem (cockpit getting warmer, cabin normal), we noticed that air was being sucked into the gaspers. Around 21000 ft, we noticed that the cabin was climbing at a higher than normal rate and leveled at 23000 ft. We realized that the cabin was not going to stop the climb as it neared 10000 ft. We elected to descend. I decided to declare an emergency and start the descent immediately. Masks in the cabin did not deploy. We leveled out at 10000 ft and looked at our options. We turned back to ord and entered holding south of cgt to make sure we had not missed anything. Also, we knew we would be making an overweight landing and wanted to be sure we had covered the checklist for that. The reason we did not burn down to 198000 pounds is that it was 87 degrees in the cockpit and we felt it was best to get on the ground. Landed on runway 32L (longest runway and into the wind) with the trucks standing by just in case. On gate arrival, one of the external air doors was noticed missing.

Original NASA ASRS Text

Title: UNABLE TO PRESSURIZE THEIR B757 AFTER TKOF FROM ORD, FLT CREW DECLARES EMER AND RETURNS TO DEP STATION. EXTERNAL AIR CONDITIONING DOOR FOUND MISSING.

Narrative: ON CLBOUT, WE NOTICED NO AIRFLOW INTO THE COCKPIT (GASPERS OR OVERHEAD). ALL INDICATIONS WERE NORMAL. LOUD RUMBLE WAS HEARD BELOW CAPT'S KIT BAG AREA FOR A FEW MINS ON CLBOUT. LOOKING INTO THE PROB (COCKPIT GETTING WARMER, CABIN NORMAL), WE NOTICED THAT AIR WAS BEING SUCKED INTO THE GASPERS. AROUND 21000 FT, WE NOTICED THAT THE CABIN WAS CLBING AT A HIGHER THAN NORMAL RATE AND LEVELED AT 23000 FT. WE REALIZED THAT THE CABIN WAS NOT GOING TO STOP THE CLB AS IT NEARED 10000 FT. WE ELECTED TO DSND. I DECIDED TO DECLARE AN EMER AND START THE DSCNT IMMEDIATELY. MASKS IN THE CABIN DID NOT DEPLOY. WE LEVELED OUT AT 10000 FT AND LOOKED AT OUR OPTIONS. WE TURNED BACK TO ORD AND ENTERED HOLDING S OF CGT TO MAKE SURE WE HAD NOT MISSED ANYTHING. ALSO, WE KNEW WE WOULD BE MAKING AN OVERWT LNDG AND WANTED TO BE SURE WE HAD COVERED THE CHKLIST FOR THAT. THE REASON WE DID NOT BURN DOWN TO 198000 LBS IS THAT IT WAS 87 DEGS IN THE COCKPIT AND WE FELT IT WAS BEST TO GET ON THE GND. LANDED ON RWY 32L (LONGEST RWY AND INTO THE WIND) WITH THE TRUCKS STANDING BY JUST IN CASE. ON GATE ARR, ONE OF THE EXTERNAL AIR DOORS WAS NOTICED MISSING.

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.

Unable to pressurize their B757 after takeoff from ord, flight crew declares emergency and returns to departure station. External air conditioning door found missing.