A B737-700's cabin altitude warning horn sounded while the aircraft was level at FL400. The memory i...

Attributes
ACN	909262
Time
Date	201009
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Pressurization Control System
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 195
Person 2
Function	First Officer Pilot Flying
Experience	Flight Crew Last 90 Days 94
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

We briefed the procedure for the cabin warning horn/abnormal pressurization prior to our first leg. Just after level off at FL400; we heard the pressurization horn sound. We immediately performed the memory items and donned our O2 masks. We then started the abnormal pressurization checklist. We requested a turn toward the nearest suitable airport. We declared an emergency and requested an emergency descent. The cabin continued to climb to approximately 13;500 ft cabin altitude. The passenger O2 masks did not deploy. The first officer was the pilot flying and I was the pilot monitoring. I ran the checklist and communicated with the passengers and the flight attendants. The landing was uneventful. We had the fire department do a cursory drive around. We then taxied to gate. Paramedics met the aircraft and two people were transported to the hospital complaining of ear pain.

Original NASA ASRS Text

Title: A B737-700's Cabin Altitude Warning Horn sounded while the aircraft was level at FL400. The memory items were completed; an emergency declared and the aircraft diverted to a nearby airport where two passengers were given medical attention for ear problems.

Narrative: We briefed the procedure for the cabin warning horn/abnormal pressurization prior to our first leg. Just after level off at FL400; we heard the pressurization horn sound. We immediately performed the memory items and donned our O2 masks. We then started the Abnormal Pressurization Checklist. We requested a turn toward the nearest suitable airport. We declared an emergency and requested an emergency descent. The cabin continued to climb to approximately 13;500 FT cabin altitude. The passenger O2 masks did not deploy. The First Officer was the Pilot Flying and I was the Pilot Monitoring. I ran the checklist and communicated with the passengers and the Flight Attendants. The landing was uneventful. We had the fire department do a cursory drive around. We then taxied to Gate. Paramedics met the aircraft and two people were transported to the hospital complaining of ear pain.

Data retrieved from NASA's ASRS site as of April 2012 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.

A B737-700's cabin altitude warning horn sounded while the aircraft was level at FL400. The memory items were completed; an emergency declared and the aircraft diverted to a nearby airport where two passengers were given medical attention for ear problems.