AD 49-09-02

49-09-02 NAVION: Applies to Airplanes Equipped With Adel Electric Booster Pumps. The Following Adel Pumps Do Not Require Modification in Accordance With This Directive: (1) Pumps With Serial Numbers above 2451, (2) Pumps Having a Red Painted Band on the Pump Housing, (3) Pumps Having the Letters "G" or "S" Suffixed to the Pump Serial Number.

To be accomplished as soon as possible but not later than April 1, 1949.

Several instances of air leakage into the fuel system have been reported on Navions equipped with Adel electric booster pumps. It has been determined that air can enter the fuel system through the 0.062-inch diameter hole in the plate at the rear of the Adel pump inlet chamber. This hole was originally provided to prevent overboard drainage of fuel through a faulty pump shaft seal while the pump was running.

All of the pumps affected require blocking of the hole at the rear of the pump inlet chamber. This is accomplished in the field by means of an Adel manufactured wire plug which is inserted into the hole through the pump inlet port. Pumps with Serial Numbers below 1600 which do not have the letter "R" suffixed to the serial number also require replacement of the pumpshaft running seal spring.

Adel Accessories Service Bulletin No. 147-49 describes these changes. The required plug and spring and copies of the Adel Bulletin and Ryan's covering Service Letter No. 57, may be obtained from the Ryan Aeronautical Co., San Diego, California.