Individually Owned: 150,657
Corporate Owned: 137,281
Long Beach Airport
Aircraft Accident/Incident Report
Long Beach, California 90808
Monday, October 22, 2001 17:00 PDT
NTSB Narrative Summary Released at Completion of Accident
A MDHI 600N helicopter, operated by the Los Angeles County Sheriff's Department, was found to have a fractured tail boom attach bolt during a routine ground examination of the helicopter for evening ground standby duty. The pilot stated that as he pushed sideways on the tail boom it seemed loose. Subsequent examination by maintenance personnel found that the head half of the upper right 5/16-inch tail boom attach bolt was hanging loose by the safety wire. Examination of the bolt revealed that it had failed about three threads from the bolt shank. The remainder of the threaded portion of the bolt remained in the plate nut affixed to the fuselage. Fretting was observed on the fuselage and tail boom mating points in proximity to the fractured bolt. Areas of the bolt shank exhibited polishing. Subsequent examination for collateral damage revealed cracks were present at the aluminum attach fitting and associated angles. The operator examined two of their other 600N helicopters and found those with cracks at the same location. Two other local area law enforcement operators also found cracks in the same location. The tail boom is attached to the fuselage with four special OEM produced bolts. The helicopter tail boom is required to be removed every 300 flight hours for inspection, and, in addition is occasionally removed for other servicing procedures. Examination of the maintenance records disclosed that the bolts may have been through about 10 torque cycles. The bolts have no life limit. The failed 5/16-inch bolt, p/n HS5482-5-18, is torqued to 150-inch/pounds during installation. On November 2, 2001, MDHI issued service bulletin SB600N-036, which prescribes procedures for inspecting the upper right tail boom, attach bolt, and attach fitting assembly. "The Part 1 inspection requirements of this bulletin shall be accomplished within the next five (5) hours of helicopter operation after the receipt of this bulletin or within thirty (30) days of the issue date of this bulletin, whichever occurs first." "The Part 2 inspection and repair requirements of this bulletin shall be accomplished within the next twenty-five (25) hours of helicopter operation after the receipt of this bulletin or within ninety (90) days of the issue date of this bulletin, whichever occurs first." On November 28, 2001, the FAA issued Priority Letter Airworthiness Directive (Emergency AD) 2001-24-51, mandating compliance with the service bulletin 600N-036.
NTSB Probable Cause Narrative
The fatigue failure of a 5/16-inch boom attach bolt was most probably caused by the angular misalignment between the tail boom bolt hole and the fuselage mounted nutplate.
Event Information
| Type of Event | Incident |
| Event Date | 10/22/2001 |
| Event Day of the Week | Monday |
| Time of Event | 1700 |
| Event Time Zone | Pacific Daylight Time |
| Event City | Long Beach |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 90808 |
| Event Date Year | 2001 |
| Event Date Month | 10 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | Long Beach |
| Event Location Nearest Airport ID | LGB |
| 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 | Not pertinent |
| 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 | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 17 |
| Dew Point at event time (in degress fahrenheit) | -- |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| 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 | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 13190 |
| NTSB Notification Source | Sheriff's Office |
| NTSB Notification Date | Oct 22 2001 12:00AM |
| NTSB Notification Time | 1700 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Apr 18 2003 4:34PM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Long Beach, CA |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N959SD |
| NTSB Number | LAX02IA013 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Public Use |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | No |
| Damage | None |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | McDonnell Douglas |
| Aircraft Model | 600N |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | RN-019 |
| Certified Max Gross Weight | 4100 |
| Aircraft Category | Helicopter |
| 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 | 5 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | -- |
| 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 | -- |
| Aircraft Owner Name | Los Angeles County Sheriff's Dept. |
| Aircraft Owner Street Address | 4700 W. Ramona Blvd |
| Aircraft Owner City | Monterey Park |
| Aircraft Owner State | CA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 91754 |
| Operator is an individual? | No |
| Operator Name | -- |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | -- |
| Operator State | -- |
| Operator Country | -- |
| Operator Zip code | -- |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Public Use |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | LGB |
| Departure City | Long Beach |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1700 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | LGB |
| Destination City | -- |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | Other |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Jan 30 2003 4:55PM |
| User who most recently changed record | COOS |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | -- |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |