AD 68-25-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Vickers-Armstrongs (Aircraft Limited) | Viscount 744 | Airworthiness Directives; VICKERS Models 744, 745D and 810 Series Airplane |
| aircraft | Vickers-Armstrongs (Aircraft Limited) | Viscount 745D | Airworthiness Directives; VICKERS Models 744, 745D and 810 Series Airplane |
| aircraft | Vickers-Armstrongs (Aircraft Limited) | Viscount 810 | Airworthiness Directives; VICKERS Models 744, 745D and 810 Series Airplane |
Unsafe Condition
Fatigue failure of the nose wheel steering twin relief valve, P/N 70026 Sh. 35 at the valve body halves P/N 70026, Part 251 and Part 253.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect valve body halves for cracks at the fluid transfer holes using dye penetrant method per specified technical leaflets. Replace valve body halves if cracks are found before further flight or according to time-in-service thresholds. Replace with inspected/crack-free or new P/N 70026-637-639 parts.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Compliance required as indicated unless already accomplished. Specific timelines depend on valve's time-in-service hours as of AD effective date: inspections and replacements must be done within specified intervals (e.g., prior to 15,000 hours, within next 350 hours, etc.) based on existing time-in-service.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Vickers-Armstrongs (Aircraft Limited) Viscount Models 744, 745D, and 810 Series airplanes.
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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