59-16-01 AERO COMMANDER: Applies to All Models 500, 520, 560, 560A, 560E, 680, 680E, 720 Aircraft, Serial Numbers 231 Through 690.
Compliance required not later than September 15, 1959.
To improve fuel line routing and to eliminate the possibility of a sump being formed between the fuel shut-off valve and the booster pump, the following inspection and/or rework is necessary.
(a) If inspection reveals excessive line lengths are creating water traps or low spots in the fuel line between the fuel shut-off valve and the fuel booster pumps, clamp the lines up to existing structure until a uniform slope is obtained.
(b) If a uniform slope cannot be obtained by clamping up the line, remove the existing 45 degrees elbow at the shut-off valve and replace it with an AN 822-8D 90 degrees elbow.
(c) If a uniform slope cannot be obtained after completing items (a) and (b), shorten fuel line until no low spots will exist upon reassembling and installation.
(d) If existing hoses cannot be shortened, new hoses may be obtained from the manufacturer or Aero Commander distributor.
See Aero Design Service Bulletin Number 54 for hose assembly part numbers and hose lengths.