Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes equipped with analog transient suppression devices (ATSDs) installed in accordance with Supplemental Type Certificate number ST00146BO. This proposed AD was prompted by multiple reports of corrosion on ATSDs. This proposed AD would require revising the maintenance program to incorporate certain limitations. We are proposing this AD to detect and correct corrosion on ATSDs, which could result in the loss of high voltage transient protection (e.g., lightning protection) in the fuel tanks and consequent fuel tank explosion and loss of the airplane.