AD 99-05-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | MD Helicopters, Inc. | MD900 | Airworthiness Directives; McDonnell Douglas Helicopter Systems Model MD-900 Helicopters |
Unsafe Condition
Fatigue failure of main rotor drive shafts, NOTAR pitch plate assemblies, and spherical/slider main rotor bearings due to exceeding established life limits.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Establish life limits for main rotor drive shafts (1,450 hours TIS), reduce life limit for NOTAR pitch plate assemblies to 3,527 hours TIS, and establish life limit for spherical/slider main rotor bearings at 12,807 hours TIS. Apply serial numbers to pitch plate assemblies on helicopters S/N 900-00002 through 900-00057. Determine time-in-service and create component history records for specified parts. Comply with Service Bulletin SB 900-058R1.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Compliance required on or before attaining specified hours TIS. Actions under paragraph (b) must be done by June 30, 1999 or 600 hours TIS after the AD's effective date, whichever comes first.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
McDonnell Douglas Helicopter Systems Model MD-900 helicopters, serial numbers 900-00002 through 900-00057 for pitch plate assembly serial numbering requirement.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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