AD 59-16-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Twin Commander Aircraft LLC | 500 | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 520 | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 560 | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 560-A | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 560-E | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 680 | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 680-E | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
| aircraft | Twin Commander Aircraft LLC | 720 | Airworthiness Directives; Aero Commander Model 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft |
Unsafe Condition
The possibility of a sump being formed between the fuel shut-off valve and the booster pump due to excessive line lengths creating water traps or low spots in the fuel line.
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Required Actions
Inspect fuel lines between the fuel shut-off valve and booster pumps. Clamp lines to existing structure for uniform slope. Replace 45-degree elbow with AN 822-8D 90-degree elbow if slope cannot be achieved. Shorten fuel lines or replace with new hoses if necessary.
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Compliance Time
September 15, 1959
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Affected Aircraft
Twin Commander Aircraft LLC models 500, 520, 560, 560A, 560E, 680, 680E, 720, serial numbers 231 through 690.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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