AD 74-22-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | DC-9-11 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-12 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-13 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-14 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-15 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-15F | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-21 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-31 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-32 | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
| aircraft | The Boeing Company | DC-9-32 (VC-9C) | Airworthiness Directives; MCDONNELL DOUGLAS DC-9 -10, -20, -30, -40, C-9A and C-9B Series Airplanes |
Unsafe Condition
Cracks in the welded aft engine isolator mounts (P/N K2219-6SA3) could result in engine separation.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the aft engine mounts per McDonnell Douglas AOL 9-786 series or equivalent. Replace cracked parts with forged P/N K2219-6SA5/K2219-7SA3 or uncracked welded P/N K2219-6SA3 before further flight. After installing forged parts, AD requirements terminate.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within next 300 hours time-in-service if mounts have over 4,000 hours at AD effective date (June 12, 1979), unless previously inspected within last 450 hours. Subsequent inspections every ≤850 hours time-in-service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
McDonnell Douglas DC-9-10, -20, -30, -40, C-9A, C-9B series with welded aft engine mounts P/N K2219-6SA3.
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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