Check of the Electrical Bonding of the Different Components (but not the Fluid Systems and Components Installed on Composite materials)

TASK 20-28-00-720-005-A
Check of the Electrical Bonding of the Different Components (but not the Fluid Systems and Components Installed on Composite materials)

WARNING: BEFORE YOU DO WORK IN OR NEAR A FUEL TANK, MAKE SURE THAT YOU OBEY ALL THE SAFETY PROCEDURES. THIS WILL PREVENT INJURY TO PERSONS AND/OR DAMAGE TO THE AIRCRAFT.

WARNING: FOR TESTS OF COMPONENTS IN THE FUEL OR FUEL VAPOR AREAS, USE ONLY THE SAFETY MILLIOHMMETER SPECIFIED IN THIS PROCEDURE. IF YOU DO NOT OBEY THIS INSTRUCTION, THE HIGH TEST CURRENTS (MORE THAN 0.1 AMPERE) CAN CAUSE YOU INJURY.

1. Reason for the Job
This test is to measure the electrical resistance with a milliohmmeter with an output test current of approximately 10 amperes for components that are not installed:

In an explosive atmosphere and
At the boundary of an explosive atmosphere.

This test also measures the electrical resistance with an ATEX milliohmmeter for components that are installed:

In an explosive atmosphere, or
At the boundary of an explosive atmosphere.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ATEX MILLIOHMMETER
No specific	1	MILLIOHMMETER MULTIRANGE

B. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-720-001-A	Check of the Electrical Bonding of the Different Components (but not Fluid Systems and Components Installed on Composite Materials) with a Millivoltmeter
TASK 20-28-00-720-006-A	Check of the Electrical Bonding of the Fluid Systems
TASK 20-28-00-869-002-A	Table of the Maximum Permitted Resistance-Values
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 28-10-00-910-001-A	Safety Procedures When You Do Work in a Fuel Tank

3. Job Set-up
Subtask 20-28-00-869-060-A

A. General
(1) This is the recommended procedure for the check of the electrical bonding of the different components (but not the fluid systems and components installed on composite materials).
For the check of the electrical bonding of the fluid systems (Ref. AMM TASK 20-28-00-720-006).
(2) As an alternative procedure (for a test with an output test current of 10 amperes), you can do the check of the electrical bonding of the components (but not the fluid systems and components installed on composite materials) with a millivoltmeter (Ref. AMM TASK 20-28-00-720-001).

Subtask 20-28-00-869-110-A

B. Preparation
(1) For test on components:

Not in an explosive atmosphere and
That do not touch an explosive atmosphere boundary.

(a) Equipment
1 Use a MILLIOHMMETER MULTIRANGE which:

Has an output test current of 10 amperes
Is set to a milliohmmeter range value higher than the maximum permitted value of the measured assembly (Ref. AMM TASK 20-28-00-869-002)
Has a precision better than +/- 10% of the measured value.

(2) For test on components that are installed:

In an explosive atmosphere, or
At the boundary of an explosive atmosphere.

NOTE: Fuel tanks and vent surge tanks are explosive atmospheres.
Fuel access panels, fuel tank walls and the walls of vent surge tanks are explosive atmosphere boundaries.

(a) Safety precautions
1 Obey the safety procedures (Ref. AMM TASK 28-00-00-910-001) and (Ref. AMM TASK 28-10-00-910-001) when you do work in a fuel tank.
(b) Equipment
1 Use an ATEX MILLIOHMMETER which:

Has an output current of maximum 0.1 A
Agrees with European Directive 2014/34/EC (ATEX European Standard)
Has a precision of 0.01 milliohms.

4. Procedure
Subtask 20-28-00-869-061-A

A. Measurement of the Electrical Resistance

CAUTION: MAKE SURE THAT YOU DO NOT CAUSE DAMAGE TO THE EQUIPMENT OR THE STRUCTURE WHEN YOU USE SHARP-POINT PRODS.

CAUTION: MAKE SURE THAT THE TEST EQUIPMENT IS CORRECTLY INSTALLED BEFORE YOU MEASURE THE BONDING VALUES.

(1) Connect the test equipment at the applicable locations (Ref. AMM TASK 20-28-00-869-002).
(2) Measure the electrical resistance.
(3) Make sure that the measured values are not higher than the maximum permitted values (Ref. AMM TASK 20-28-00-869-002).

5. Close-up
Subtask 20-28-00-942-094-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.

[Rev.10 from 2021] 2026.04.01 04:50:57 UTC