Emb-145XR first officer reported after departure cabin began to depressurize at FL240. Crew ran the ...

Narrative:

We departed uneventfully and leveled off at FL240. We heard the master warning and saw the cabin altitude in the red box showing 10;000 feet and climbing. We ran the automatic prsn QRH and noticed the cabin altitude still rising. The captain declared an emergency and after notifying ATC we descended down to 10;000 feet. As the cabin altitude was increasing [I] and the captain donned our oxygen masks. The cabin oxygen masks deployed for the passengers. We were eventually via manual control (pressurization) able to bring down the cabin altitude. We returned to [departure airport] and landed uneventfully. We were however 400 lbs over our structural landing weight. After landing we were met by the arff and we let them know we were okay to taxi to the gate. Take time when running the QRH. Be methodical and efficient.

Original NASA ASRS Text

Title: EMB-145XR F/O reported after departure cabin began to depressurize at FL240. Crew ran the QRH; declared an emergency; and returned to departure airport.

Narrative: We departed uneventfully and leveled off at FL240. We heard the master warning and saw the cabin altitude in the red box showing 10;000 feet and climbing. We ran the AUTO PRSN QRH and noticed the Cabin Altitude still rising. The Captain declared an emergency and after notifying ATC we descended down to 10;000 feet. As the Cabin Altitude was increasing [I] and the Captain donned our oxygen masks. The cabin oxygen masks deployed for the passengers. We were eventually via manual control (pressurization) able to bring down the Cabin Altitude. We returned to [departure airport] and landed uneventfully. We were however 400 lbs over our structural landing weight. After landing we were met by the ARFF and we let them know we were okay to taxi to the gate. Take time when running the QRH. Be methodical and efficient.

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	1057411
Time
Date	201212
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Component
Aircraft Component	Pressurization System
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

Emb-145XR first officer reported after departure cabin began to depressurize at FL240. Crew ran the QRH; declared an emergency; and returned to departure airport.