Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Indianapolis, Indiana 46241
Sunday, May 12, 1996 20:25 CDT
NTSB Narrative Summary Released at Completion of Accident
Upon reaching a cruise altitude of 33,000 feet, the cabin altitude warning horn sounded. The captain noticed the right air conditioning pack was off and he, along with the flight engineer, attempted to reinstate the pack without using a checklist. The cabin altitude continued to climb to 14,000 feet at which time the warning lights illuminated and the oxygen masks deployed in the cabin. While attempting to correct the cabin altitude, the flight engineer inadvertently opened the outflow valve resulting in a rapid loss of cabin pressure. The captain, the flight engineer, and the lead flight attendant all subsequently became unconscious due to hypoxia. The captain had delayed donning his oxygen mask. The flight engineer became unconscious after reviving the flight attendant. The first officer, who had only 10 hours of flight time in the airplane, had donned his oxygen mask when the warning horn first sounded, maintained consciousness, and was able to initiate an emergency descent. During the emergency descent the captain, the flight engineer, and the attendant regained consciousness, and an emergency landing was made at Indianapolis, Indiana. The airplane was inspected and flight tested the next day. The airplane's pressurization system functioned with no anomalies.
NTSB Probable Cause Narrative
the failure of the captain and flight engineer to utilize a checklist to troubleshoot a pressurization system problem, and the flight engineer's improper control of the pressurization system which resulted in an inadvertent opening of the outflow valve and subsequent airplane decompression.
Event Information
| Type of Event | Incident |
| Event Date | 5/12/1996 |
| Event Day of the Week | Sunday |
| Time of Event | 2025 |
| Event Time Zone | Central Daylight Time |
| Event City | INDIANAPOLIS |
| Event State | INDIANA |
| Event Country | -- |
| Zipcode of the event site | 46241 |
| Event Date Year | 1996 |
| Event Date Month | 5 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | |
| Event Location Nearest Airport ID | |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | Unknown |
| Investigator's weather source | Pilot |
| Time of the weather observation | 0 |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | |
| Elevation of weather observation facility | 0 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | |
| Lighting Conditions | Night/Dark |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 0 |
| Air Temperature at event time (in degrees celsius) | -- |
| Dew Point at event time (in degress fahrenheit) | 3 |
| Wind Direction (degrees magnetic) | 320 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | 11 |
| Injury Total None | 101 |
| Injury Total Serious | -- |
| Injury Total All | 11 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 5015 |
| NTSB Notification Source | -- |
| NTSB Notification Date | May 13 1996 12:00AM |
| NTSB Notification Time | 730 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Dec 8 2000 9:59AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N775AT |
| NTSB Number | CHI96IA157 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Boeing |
| Aircraft Model | 727-290 |
| Aircraft Series Identifier | 727-290 |
| Aircraft Serial Number | 21511 |
| Certified Max Gross Weight | 197700 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 181 |
| Number of Engines | 3 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Dec 5 1995 12:00AM |
| Airframe hours since last inspection | 1261 |
| Airframe Hours | 47305 |
| ELT Installed | No |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | GATX THIRD AIRCRAFT CORP. |
| Aircraft Owner Street Address | FOUR EMBARCADERO STR. STE 200 |
| Aircraft Owner City | SAN FRANCISCO |
| Aircraft Owner State | CA |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 94111 |
| Operator is an individual? | -- |
| Operator Name | AMERICAN TRANS AIR |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 7337 W. WASHINGTON ST. |
| Operator City | INDIANAPOLIS |
| Operator State | IN |
| Operator Country | |
| Operator Zip code | 46231 |
| Operator Code | AMTA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | MDW |
| Departure City | CHICAGO |
| Departure State | IL |
| Departure Country | |
| Departure Time | 2000 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | PIE |
| Destination City | ST. PETERSBURG |
| Destination State | FL |
| Destination Country | |
| Specific Phase of Flight | Cruise |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 20 2002 12:42PM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |