Individually Owned: 150,657
Corporate Owned: 137,281
Douglas International Airport
Aircraft Accident/Incident Report
Charlotte (Clt), North Carolina 28208
Wednesday, July 15, 2009 8:30 EST
NTSB Narrative Summary Released at Completion of Accident
On July 15th, 2009, US Airways reported that the Left Hand (LH) Main Landing Gear (MLG) from the incident airplane was found to have a hydraulic fluid leak through a pin hole on the forward side of the outer cylinder. The leaking gear was sent to AAR Landing Gear Services (LGS) where ultrasonic inspection found crack indications approximately 31 inches from the open end of the outer cylinder. The main landing gear was disassembled and subsequent magnetic particle inspection found a long, sharp indication through the chrome plating in the working inner diameter (ID) section of the outer cylinder. The subject outer cylinder was sent to Boeing Material and Process Technology in Seattle Washington for fracture analysis.
It was reported that the subject outer cylinder had been through three overhauls, the first two being performed by US Airways. It was further reported that during the first two overhauls, US Airways did not perform any rework on the working ID of the cylinder. AAR performed the
last overhaul and it was reported that at that time, corrosion was found and removed from the working ID section of the cylinder in accordance with the component maintenance manual (CMM). The oversized ID surface was then chrome plated and ground to the design diameter.
AAR overhauled the LH MLG in December 2008, and it was installed in the incident airplane in April 2009. The subject gear accumulated a total cycles of 40,639 (379 since last overhaul) and a total hours of 59,837 (606 since last overhaul).
A crack measuring 1.95” was present on the working ID on the forward side of the outer cylinder. Several microcracks of varying lengths were also found present on this region. The primary crack was made up of three cracks that had linked together. The cracks originated from heat induced cracks that were present on the ID surface and propagated primarily by fatigue towards the outer diameter (OD) surface of the cylinder. The microcracks that were present on the region originated and propagated in a similar manner. The heat induced cracks were the result of abusive grinding/polishing of the chrome plate that was applied during the last overhaul.
NTSB Probable Cause Narrative
The failure of the left hand main landing gear was caused by heat induced cracks resulting from abusive grinding/polishing of the chrome plate that was applied during the last overhaul.
Event Information
| Type of Event | Incident |
| Event Date | 7/15/2009 |
| Event Day of the Week | Wednesday |
| Time of Event | 830 |
| Event Time Zone | Eastern Standard Time |
| Event City | Charlotte (CLT) |
| Event State | NORTH CAROLINA |
| Event Country | -- |
| Zipcode of the event site | 28208 |
| Event Date Year | 2009 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | Douglas International |
| Event Location Nearest Airport ID | CLT |
| 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 | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Unknown |
| Time of the weather observation | |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | -- |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | -- |
| Lighting Conditions | -- |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | -- |
| Sky Condition for Lowest Ceiling | -- |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | -- |
| Air Temperature at event time (in degrees celsius) | -- |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | -- |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | -- |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 28209 |
| NTSB Notification Source | Federal Aviation Aministration |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Mar 31 2011 11:37AM |
| User who most recently changed record | murb |
| Basic weather conditions | -- |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N506AU |
| NTSB Number | ENG09IA009 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | Unknown |
| Flight plan Was Activated? | No |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BOEING |
| Aircraft Model | 737-3B7 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 23381 |
| Certified Max Gross Weight | 135000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | -- |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Unknown |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | -- |
| ELT Installed | No |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | AIRCRAFT STATUTORY TRUST N506AU |
| Aircraft Owner Street Address | C/O US BANK TRUST NA TR |
| Aircraft Owner City | BOSTON |
| Aircraft Owner State | MA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 02110 |
| Operator is an individual? | No |
| Operator Name | US AIRWAYS INC |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 4000 Sky Harbor |
| Operator City | Phoenix |
| Operator State | AZ |
| Operator Country | USA |
| Operator Zip code | 85034 |
| Operator Code | USAA |
| 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 | USAA105A |
| 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 | -- |
| Departure City | -- |
| Departure State | -- |
| Departure Country | USA |
| Departure Time | -- |
| Departure Time Zone | -- |
| Destination Same as Local Flt | -- |
| Destination Airport Code | -- |
| Destination City | -- |
| Destination State | -- |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Nov 17 2010 2:11PM |
| User who most recently changed record | murb |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |