AD 77-02-08

77-02-08 NARCO: Amendment 39-2818. Applies to all Narco Model ELT-10 77 Emergency Locator Transmitter batteries, with a battery replacement date prior to November 1977.

Compliance required as indicated.

As a result of battery corrosion which results in battery lead breakage and the resulting failure of the ELT to operate, accomplish the following:

(a) Within the next 90 days and thereafter, at each additional 90-day interval after the effective date of this Airworthiness Directive, accomplish the following:

1. Remove the control head from battery pack by removing four screws.

2. Check for battery leakage, which will appear as a white residue which normally occurs first around battery leads.

3. Check for corrosion at the battery terminals, printed circuit board and components.

4. Check for secure battery leads.

5. If no corrosion is found, determine ELT transmits properly in accordance with FAA Advisory Circular 91-44 or 20-81, and reinstall in accordance with paragraph 8 of the Narco Owner's Manual or approved alternate installation procedures.

6. If corrosion is found, replace battery (Narco P/N 57674-0001) with one which has a replacement date of November 1977, or later.

7. The checks required by this Airworthiness Directive may be conducted by the pilot or aircraft owner.

(Narco Service Bulletin ELT-10 No. 6, dated August 2, 1976, covers this same subject.)

This amendment is effective February 1, 1977.