76-13-05 BEECH: Amendment 39-2653. Applies to Models E55 and E55A (Serial Numbers TE-969 thru TE-1009, TE-1011 thru TE-1021, TE-1023 thru TE-1029 and TE-1032 thru TE-1034 airplanes; Models 58 and 58A (Serial Numbers TH-441 thru TH-482, TH-484 thru TH-541, TH-543 thru TH-547, TH-549 thru TH-555, TH-557 thru TH-595, TH-597 thru TH-602, TH-604, TH-605, TH-607 and TH-609) airplanes; Model B60 (Serial Numbers P-272 thru P-307, P-309 thru P-326, P-328 thru P-330), and Model BH125-600A (Serial Numbers 256001, 256002, 256004, 256007, 256009, 256010, 256011, 256013, 256014, 256016, 256018, 256020, 256022, 256023, 256032, and 256034) airplanes.
Compliance: Required as indicated, unless already accomplished.
To prevent complete loss of electrical power or damage to the engine firewall, either within the next 100 hours' time in service after the effective date of this AD, or at the next 100 hour, annual or progressive inspection after the effective date of this AD, whichever alternative occurs first, accomplish the following:
A) Inspect the terminal block assemblies and rework or replace where necessary in accordance with the following procedures:
1. Locate the terminal block assemblies mounted on:
(a) The aft right side of the forward cabin bulkhead on Models E55, E55A, 58 and 58A.
(b) The inboard side of the left nacelle firewall and the outboard side of the right nacelle firewall on Model B60. Both are on the forward side of the firewall.
(c) The APU relay panel assembly and the right hand side of the horizontal cross member at frame 24 on Model BH125-600A.
2. Disconnect the battery and remove structure as necessary to gain access to the terminal block assemblies.
3. Remove the current limiters from the terminal block assemblies and then remove the terminal block assemblies.
4. Visually inspect the terminal block assemblies to determine if the bolt heads are properly recessed. A properly recessed bolt should be mounted from .010 inches to .070 inches below flush within the terminal block base.
5. If the bolt heads are not properly recessed, either remove the bolts and rework the holes to accept the bolt heads at the correct depth or discard the terminal block assembly and install a Beech P/N 103-27 terminal block assembly.
6. Inspect the insulator strips. If they are cracked or broken, either fabricate new strips from equivalent phenolic material or obtain new strips, Beech P/N 103-26.
7. Reinstall the terminal block assemblies, current limiters and all removed structure. Reconnect the battery.
B) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.
Beechcraft Service Instructions Nos. 0754-350 for models E55, E55A, 58, 58A and B60 and No. 125-018, Rev. 1 for model BH125-600A or later FAA-approved revisions cover the subject matter of this AD.This amendment becomes effective July 6, 1976.