Individually Owned: 150,657
Corporate Owned: 137,281
Chicago O'hare International Airport
Aircraft Accident/Incident Report
Chicago, Illinois 60018
Monday, December 15, 2008 22:39 CST
NTSB Narrative Summary Released at Completion of Accident
During the landing approach, the landing gear "Gear Disagree" warning message appeared. The flight crew performed the appropriate emergency checklists without success. An emergency landing was conducted with a fully extended nose and right main landing gear, but the left main landing gear was not extended. The pilot reported that he was able to keep the left wing up for only a few seconds before it contacted the runway. The airplane skidded to a stop with the left wing supported by the wing flaps and the outboard leading edge slats. The inspection of the airplane revealed that the landing gear belly fairing was fractured. The inspection further indicated that the left main landing gear door had intruded over the belly fairing and weather seal at the fracture area, and had become "hung up" and was not able to extend to the down position. The clearance between the left landing gear door and the belly fairing was measured while the landing gear was in the stowed position. The investigation revealed that the manufacturer’s Aircraft Maintenance Manual (AMM) did not specify the clearance measurement for zone “E”, which was the zone that corresponded to the fractured belly fairing. A review of the airplane’s maintenance records indicated that the left main landing gear door had been replaced at the manufacturer's heavy maintenance facility in September 2007. A maintenance review revealed that the door was rigged and checked with the use of the aircraft hydraulic pumps instead of the external hydraulic power unit as required by the AMM.
As a result of the investigation findings, the following safety actions were taken:
1. On December 23, 2008, Bombardier issued Service Letter CRJ700/900-SL-32-039, “Body Fairing Seal Inspection Common to MLG Inboard Door” to provide operators with guidelines for inspecting the body fairing seal common to the main landing gear inboard doors at the next convenient maintenance opportunity (i.e., 72 hour or 100 flight hours).
2. On December 24, 2008, Bombardier issued Reference Instruction Letter (RIL) No. 1583, "Clarification of clearance for MLG door installation." It stated that it was permissable to use the clearances shown in AMM 32-12-01-220-801-A02 Fig 502 during utilization of AMM 32-12-01-220-801-A01 Figure 501.
3. On January 28, 2009, the Federal Aviation Administration (FAA) issued a Special Airworthiness Information Bulletin (SAIB) No. NM-09-06. The SAIB stated that the FAA “strongly recommends that the affected operators comply with Bombardier Service Letter CRJ700/900-SL-32-039 at the earliest opportunity.”
4. Mesa Airlines conducted a fleetwide inspection of their aircraft and found no other door seal anomalies. Bombardier plans to issue a revised AMM procedure to indicate the proper clearances for zone E. The FAA plans to issue an AD once Bombardier makes the revision to the AMM.
NTSB Probable Cause Narrative
The failure of the left landing gear to extend due to improper maintenance when the landing gear door was replaced. Contributing to the incident was the manufacturer's inadequate maintenance manual instructions.
Event Information
| Type of Event | Incident |
| Event Date | 12/15/2008 |
| Event Day of the Week | Monday |
| Time of Event | 2239 |
| Event Time Zone | Central Standard Time |
| Event City | Chicago |
| Event State | ILLINOIS |
| Event Country | -- |
| Zipcode of the event site | 60018 |
| Event Date Year | 2008 |
| Event Date Month | 12 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 415851N |
| Event Location Longitude | 0875423W |
| Event Location Airport | Chicago O'Hare International |
| Event Location Nearest Airport ID | ORD |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 672 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 2253 Central Standard Time |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | ORD |
| Elevation of weather observation facility | 672 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | CST |
| Lighting Conditions | Night |
| Lowest Ceiling Height | 20000 |
| Lowest Non-Ceiling Height | 2100 |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | -12 |
| Dew Point at event time (in degress fahrenheit) | -17 |
| Wind Direction (degrees magnetic) | 360 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.59 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | KDFW 160453Z 36010KT 8SM BKN010 OVC014 M03/M07 A30 |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 32 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 25748 |
| NTSB Notification Source | FAA-AGL-ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Sep 30 2009 10:03AM |
| User who most recently changed record | lema |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N511MJ |
| NTSB Number | CEN09FA094 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | Yes |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOMBARDIER |
| Aircraft Model | CL-600-2C10 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 10104 |
| Certified Max Gross Weight | 75250 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | 2 |
| Passenger Seats | 64 |
| Total number of seats on the aircraft | 64 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Dec 13 2008 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 14596 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | First Union National Bank Trustee |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Charlotte |
| Aircraft Owner State | NC |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 28288 |
| Operator is an individual? | No |
| Operator Name | Mesa Airlines, Inc |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 410 North 44th Street, Suite 700 |
| Operator City | Phoenix |
| Operator State | AZ |
| Operator Country | USA |
| Operator Zip code | 85008 |
| Operator Code | MESA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| 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) | -- |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | ORD |
| Departure City | Chicago |
| Departure State | IL |
| Departure Country | USA |
| Departure Time | 2100 |
| Departure Time Zone | CST |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | ORD |
| Destination City | Chicago |
| Destination State | IL |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jun 23 2009 6:14PM |
| User who most recently changed record | silj |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 28 |
| Runway Length | 13000 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |