Ground Bond Testing for Production and Maintenance

Summary

Why measure bonding resistance ? RCP2A Presentation RCP2APro software RCP2A advantages Customer targets

The effects of lightning strikes ?

Lightning : a danger for planes! On average every civil transport aircraft is struck by

lightning in flight once a year The risk of strikes by lightning is increased in rainy

zones, at approximately 4000 meters and between -5°C and +5°C

During a strike by lightning, the lightning does not stop on the plane but sweeps it to continue its way in the atmosphere with a point of initial entrance and a point of final exit

Direct effects of lightningStrikes

They are caused by the effect of the discharge or by the conduction of the lightening strike current (up to 200 kA!)

Types of the damage: Thermic with perforation of walls by fusion Dynamic with rise of pressure which generates a

destructive shock wave for the cabling and the dissimilar and composite materials.

Electromagnetic which perturbs the on board equipment

Direct effects of lightning Strikes

Why measure the bonding resistance ?

A plane with a structure and a metal envelope (aluminium) constitutes an excellent protection against lightning strikes provided electric continuity is insured

Connection of dissimilar materials can cause a weakness in the electric conductivity and prevent the effective discharge of electric loads received by the plane

The bonding of these surfaces becomes indispensable and thus the control of this bonding and the continuity

RCP2A > The right solution for bonding resistance measurement

according to all current aircraft specifications

Bonding resistance measurement with new Sefelec Milliohmmeter RCP2A

RCP2AThe milliohm meter RCP2A is a measuring device

of resistances from 100 µ to 6 with currents of 0.1 A, 1 A or 10 A.

Presented in a fibreglass and resin polyester box of small dimensions (340x120x220 mm) with a weight of 4 kg, its ergonomics allows the user to use it either placed on the ground or across one’s shoulder or chest.

A wide back-lit LCD display combined with an intuitive keyboard ensure simple and easy operation.

Specifications

Range Current Resolution Precision

6 m 1A / 10A 1µ (0,1% lect+0,1% PE)

60 m 1A / 10A 10µ (0,1% lect+0,1% PE)

600 m 1A / 10A 100µ (0,1% lect+0,1% PE)

6000 m 0,1A / 1A 1m (0,1% lect+0,1% PE)

RS232 interface 1000 measures with 10A Removable battery pack Remote control at distance Suite case A wide range of accessories

Front panel

Measure terminalsMeasureEnter key

Red/Green light LCD sreen Joystick Batteries

Start/Stop Function keys

Removable battery module Extraction handle RS232 socket

Charger socket

Locking screw

Measurement press button

Locking screw

Measurement method In order to make low resistance measurement with a high precision, the RCP2A uses the 4 wire Kelvin method.

2 wires are used to connect a constant current source to the resistance to be measured

2 additional wires are used to measure the difference of potential directly to the terminals of the device under test.

With this method, the resistance of the measuring leads does not introduce any error.

Kelvin Method

-I

RLead

RLead

RLead

RxIc

+I

+U

-U

RLead

Ux

Rx = Ux / Ic

RCP2A Accessories (leads etc.)

Bonding resistance

RLead = Lead resistance

RCP2APro software

RCP2A Software / Sequence mode

RCP2APro is a powerfull, easy-to-use and user-friendly software that creates the interface between RCP2A and PC

It allows to program test sequences using EXCEL™, according to Ground Test Instructions. A sequence describes the points of bonding to be tested, along with test parameters (current and maximum resistance)

RCP2A Software / Sequence mode

• In this modele example, Mr DUPONT has been programing 15 points for 4 different sections of an A380, with the below specifications

RCP2A Software / Sequence mode

Through RS232 or USB interfaces, the EXCEL™ sequence is loaded into the RCP2A with the RCP2APro graphic interface

RCP2A Software / Sequence mode

The user clearly sees on the LCD Display the loaded sequence and the list of points he has to measure

RANGES: NOZE LEFT WING RIGHT WING TAIL

END

RCP2A

MANUEL SEQU TEST CONF

LEFT WING S : 150.0 mΩ I : 10A BAT. : 80%

020: - - - - m

POINT ABSENT VALID CONF END

Once the points have been measured and stored in the RPC2A, the PC can upload all the measurements, for direct saving, and results traceability

032: 98.3 POINT ABSENT VALID CONF END

m

LEFT WING S : 150.0 mΩ I : 10A BAT. : 80%

RCP2A Software / Sequence mode

• In this result example, Mr DUPONT has been testing 15 points from 4 different sections of an A380, with the below results

RCP2A Software / Sequence mode

RCP2A advantages

Measurement specifications Ergonomics > small weight and volume User friendly interfaces Replaceable batteries of big capacity Measurement traceability through the SEQUENCE mode Remote control with LCD display RS232 interface with PC download/upload facility Wide accessory range Measurement up to 100 meters Approval of the equipment by Airbus Partial testing (possibility to upload started results to the PC, and

then download them again to the RCP2A to finish the tests)

RCP2A typical customers

AIRBUS BOEING DASSAULT EUROCOPTER EMBRAER FOKKER X.A.C., …

Manufacturers of civil and military aircrafts

RCP2A typical customers

SOGERMA TURBOMECA HISPANO SUISA INTERTECHNIQUE, BF GOODRICH, …

The subcontractors

RCP2A typical customers

AIR FRANCE, LUFTHANSA TECHNIK AIA LABINAL JAL, AIR CHINA, KOREAN, INDIAN airlines,

ALITALIA, AUSTRIAN, THAI, TAP, SR TECHNICS, …

Airlines & maintenance companies