Advisory Circular (AC) No. 500-005 Issue 1

Fire Protection - Ignition Sources

File No. 5009-6-500 AC No. 500-005
RDIMS No. 528233-V2 Issue No. 01
Issuing Branch Aircraft Certification Effective Date 2004-12-01

1.0 Introduction

1.1 Purpose
1.2 Guidance Applicability
1.3 Description of Changes
1.4 Termination

2.0 References

2.1 Reference Documents
2.2 Cancelled Document

3.0 Background

4.0 Acceptable Means of Compliance

5.0 Headquarters Contact

1.0 Introduction

1.1 Purpose

The purpose of this Advisory Circular (AC) is to provide guidance material for acceptable means, but not the only means, of demonstrating compliance with the requirements of sections 523.863(a), 525.863(a), 527.863(a) and 529.863(a) of the Airworthiness Manual (AWM) dealing with electrical and electronic equipment and hot surfaces as ignition sources.

1.2 Guidance Applicability

This document is applicable to all Transport Canada personnel, delegates and industry.

1.3 Description of Changes

This document, formerly AMA No. 500C/3, is reissued as an AC. The reference documents and the content have been reviewed and updated.

1.4 Termination

This document does not have a terminating action. It will however, be reviewed periodically for suitability of content.

2.0 References

2.1 Reference Documents

It is intended that the following reference materials be used in conjunction with this document:

(a) Chapter 523 of the Airworthiness Manual (AWM) - Normal, Utility, Aerobatic and Commuter Category Aeroplanes;
 
(b) Chapter 525 of the AWM - Transport Category Aeroplanes;
 
(c) Chapter 527 of the AWM - Normal Category Rotorcraft;

(d) Chapter 529 of the AWM - Transport Category Rotorcraft;
 
(e) Federal Aviation Administration Advisory Circular (FAA AC) 25-10 - Guidance for Installation of Miscellaneous Non-required Electrical Equipment; and
 
(f) FAA AC 25-16 - Electrical Fault and Fire Prevention and Protection.

2.2 Cancelled Document

As of the effective date of this document, AMA No. 500C/3 dated 1 May 1996 is cancelled.

3.0 Background

The possibility exists whereby the failure of electrical/electronic equipment (e.g. generator bearing failure or winding burnout), may cause excessive overheating of the cooling air and possibly molten metal to be ejected into the areas where flammable fluids or vapour might be present. A hot surface (e.g. a cooling duct or an exhaust duct) can also be a source of ignition.

4.0 Acceptable Means Of Compliance

The cooling air for any electrical/electronic equipment should be supplied and discharged so as not to create a hazard following failure of the equipment. Where necessary the cooling air ducting should meet the flammability standards that are part of the basis of certification for the type certified aeronautical product. FAA AC 25-10 provides some guidance for installation of miscellaneous, non-required electrical equipment while FAA AC 25-16 provides guidance on electrical fault and fire prevention and protection.

If the temperature of a surface, which may be exposed to flammable fluids or vapours, can exceed (under normal or failure conditions) a dangerous value with regard to these materials, then:

(a) the surface should be protected against the impingement of flammable fluids; and
 
(b) the zone containing the surface should be ventilated and drained so as to preclude ignition of flammable vapours.

Unless a higher value can be substantiated, a surface temperature in excess of 200°C is considered hazardous.

5.0 Headquarters Contact

For more information please contact:

Policy Standards Coordinator (AARDH/P)
Phone: (613) 990-3923
Facsimile: (613) 996-9178
E-mail: AARDH-P@tc.gc.ca

Original signed by Maher Khouzam

Maher Khouzam
Chief, Regulatory Standards
Aircraft Certification Branch

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