REPORT #:

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This document is the property of Field Aviation Company Inc., an Alberta corporation. By accepting this document for

reference, the recipient agrees to hold Field Aviation Company Inc. harmless from any liabilities arising from the use or

misuse of this document or the information contained therein. Duplication, disclosure to others or use for manufacturing

purposes is not authorized without the prior written consent of Field Aviation Company Inc. 

# DESIGN COMPLIANCE IT EMS

FAA SUPPLEMENT

AUXILIARY F UEL SYSTEM

BOMBARDIER DHC

- 8 100/200/300 SERIESREPORT #:

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- MAY

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## LOG OF REVISIONS

Rev. Date Description of Revision Prepared Checked Approved

IR 0 1

- May

- 1 2 Initial Release M. Hales C. Marsetti W. SpriggREPORT #:

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## TABLE OF CONTENTS

1.0 INTRODUCTION

................................ ................................ ................................ ............................ 4

1.1 PURPOSE

................................ ................................ ................................ ............................... 4

1.2 SCOPE

................................ ................................ ................................ ................................ .... 4

1.3 APPLICABLE REQUIREME NTS

................................ ................................ ............................ 4

1.4 DESCRIPTION

................................ ................................ ................................ ........................ 4

1.5 ABBREVIATI ONS

................................ ................................ ................................ ................... 4

2.0 COMPLIANCE STATEMENT MATRIX

................................ ................................ .......................... 5

APPENDIX A

APPENDIX B

APPENDIX CREPORT #:

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### 1.0 INTRODUCTION

1.1 PURPOSE

Field Aviation is seeking regulatory approval in the form of a Supplementary Type Certificate

(STC) for the auxiliary fuel system for the DHC

- 8 Series 100, 200 & 300 aircraft.

1.2 SCOPE

This report provides statements of compliance against regulatory requirements.

Th e scope of this rep ort includes structural, mechanical, electrical, and systems drawings and

reports that are relevant to the compliance with FAA paragraphs listed below

. For clarification of the regulatory requirements and associated means of compliance, review the

Complian ce Program, Field Aviation Report 2537010 1

.

1.3 APPLICABLE REQUIREME NTS

The applicable basis of certification, aircraft type approval and regulatory requirements are

detailed in Field Aviation Report 25370100.

1.4 DESCRIPTION

For a detail description of the auxili ary fuel tank system refer to Field Aviation Engineering

Report 20133

.

1.5 ABBREVIATIONS

N/A Not Applicable

OEM Original Equipment Manufacturer

STC Supplementary Type CertificateREPORT #:

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### 2.0 COMPLIANCE STATEMENT MATRIX

AIRWORTHINESS

REQUIREMENTS SUBJECT Compliance

Statement Reference

FAA PARAGRAPH CERTIFICATION SPECIFICATION

SUBPART E

- POWERPLANT

25.981 (a) Fuel Tank Ignition Prevention

Compliant. Refer to Safety Assessment Table and Fault

Tree Diagram Refer to

2537010 5

, Appendix A &

C

25.981 (a)(1) Compliant. The minimum auto

- ignition temperature for the

fuels listed on the aircraft’s Type Certificate (Jet A, A

- 1, JP

4, JP

- 5, JP

- 8 & Jet B) is 410oF. Refer to Safety

Assessment Table

. Refer to

2537010 5

, Appendix A

25.981 (a)(2)

Compliant. Refer to Safety Assessment Table and Fault

Tree Diagram Refer to

2537010 5

, Appendix A &

C

25.981 (a)(3)

Compliant to maximum extent possible. Refer to Safety

Assessment Table and Fault Tree Diagram. Refer to

2537010 5

, Appendix A &

C

2 5.981 (b)( 1 ) Compliant.

The DHC

- 8

- 200 is a high wing, subsonic aircraft primarily

constructed of aluminum. The conventional, all aluminum

and uninsulated wings contain integral fuel tanks and can

carry Jet A, Jet A

- 1 , JP

- 4, JP

- 5, JP

- 8 or Jet B fuel. The

tanks are equa lized with the external environment pressure

via venting. Appendix A of this report contains a list of all

internal and external heat sources. Being part of the wing,

the tank is part of a large aerodynamic surface that is

exposed to outside air. The Auxil iary tank ratio of surface

area to fuel volume is 1.26 which exceeds the ratio of 1.0

as specified in FAA Advisory Circular AC 25.981

- 2A

(Section 10). By Design Auxiliary Fuel System bottom

feeds both the Auxiliary and Main tanks and all tanks are

vented t o atmosphere

.

25.981 ( b )(2) N/A. Auxiliary tanks are not located within the fuselage

contour.

25.981 (b)(3)(i) Compliant.

The DHC

- 8

- 200 is a high wing, subsonic aircraft primarily

constructed of aluminum. The conventional, all aluminum

and uninsulated wings contain integral fuel tanks and can

carry Jet A, Jet A

- 1 or Jet B fuel. The tanks are equalized

with the external environment pressure via venting.

25.981 b(3)(ii) Compliant

Appendix A of this report contains a list of all internal and

external heat sources. Being part of the wing, the tank is

part of a large aerodynamic surface that is exposed to

outside air. The Auxiliary tank ratio of surface area to fuel

volume is 1.26 which exceeds the ratio of 1.0 as specified

in FAA Advisory Circ ular AC 25.981

- 2A (Section 10). By

Design Auxiliary Fuel System bottom feeds both the

Auxiliary and Main tanks and all tanks are vented to

atmosphere Refer to

2537010 5

, Appendix A

25.981 b(3)(iii) N/A.

Auxiliary Tank system does not feed fuel directly into the

engines

2 5.981 (c) Paragraph (b) appliesREPORT #:

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AIRWORTHINESS

REQUIREMENTS SUBJECT Compliance

Statement Reference

25.981(d) Compliant. Inspection Procedures defined in Maintenance

Manual Supplements MMS20452 &

25370111

SPECIAL CONDITION

26.11 Enhanced Airworthiness Program for Airplane

Systems

- ICA on EWIS Compliant. EWIS Analysis and Task Reports 25370110 &

25370111 are provided as the method of compliance with

this paragraph 25370110/

25370111REPORT #:

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### A PPENDIX A

- SAFETY ASSESSMENT OF AUXILIARY FUEL TANK



## 1. Compliance Statements regarding HIRF, Indirect Effects of Lightning &

Single Point Ignition ( Ref, Advisory Circular 25.981

- 1C )

1) Fu el System Wiring Harness Protection External to the Tank

– HIRF

Metho d A

- One Level of Safety Mitigation

 Wire Harness Routing Drawings

 Drawing note stipulating the requirement for separate routing.

Method B

- Two Levels of Safety Mitigation

 Double Shielding of Fuel Tank Wiring harnesses

Method C

- One Level of Safety Mitigation

 Transient Protection

– Solid State devices, example

– Transorb

Method D

- One Level of Safety Mitigation

 Airframe Electrical Field Attenuation

– (

- 20 db) protection afforded to areas

completely enclosed within metallic structure.

Note:

ICA must include periodic shield continuity testing as part of interval inspection

criteria

.



## 2) Powered Components Within a Tank

- HIRF

Method A

- Two Levels of Safety Mitigation

 Component Bonding

– Redundant Paths

Method B

- One Level of Safety Mitigation

 Wire Conductor Shielding

Method C

- One Level of Safety Mitigation

 Component internal construction

– Electrical/ Fuel/ Vapo r isolation example

Explosion proofing, Vacuum isolation.

Method D

- One Level of Safety Mitigation

 Airframe Electrical Field Attenuation

– (

- 20 db) protection afforded to areas

completely enclosed within metallic structure.

Method E

- One Level of Safety Mitigation

 Transient Protection

– Solid State devices, example

- TransorbREPORT #:

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## 3) Non

- Powered Components within a Tank

- HIRF

Method A

– 2 levels of Safety Mitigation

 Component Bonding

– Redundant Paths, example, bonding jumpers

connected to adjacent structure

Method B

– One Level of Safety Mitigation

 Direct Component Bonding

– Structural Contact

Method C

- One Level of Safety Mitigation

 Airframe Electrical Field Attenuation

– (

- 20 db) protection afforded to areas

completely enclosed within metallic structure.



## 4) Fu el System Wiring Harness Protection External to the Tank

– Indirect

Effects of Lightning

Method A

- One Level of Safety Mitigation

 Wire Harness Routing Drawings

 Drawing note stipulating the requirement for separate routing.

Method B

- Two Levels of Safety Mitigation

 Double Shielding of Fuel Tank Wiring harnesses

Method C

- One Level of Safety Mitigation

 Transient Protection

– Solid State devices, example

– Transorb

Note:

ICA must include periodic shield continuity testing as part of int erval inspection

criteria

.



## 5) Powered Components Within a Tank

– Indirect Effects of Lightning

Method A

- Two Levels of Safety Mitigation

 Component Bonding

– Redundant Paths

Method B

- One Level of Safety Mitigation

 Wire Conductor Shielding

Method C

- One Level of Safety Mitigation

 Component internal construction

– Electrical/ Fuel/ Vapo r isolation example

Explosion proofing, Vacuum isolation.

Method D

- One Level of Safety Mitigation

 Transient Protection

– Solid State devices, example

- TransorbREPORT #:

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## 6) Non

- Powered Components within a Tank Tank

– Indirect Effects of

Lightning

Method A

– Two levels of Safety Mitigation

 Component Bonding

– Redundant Paths, example, bonding jumpers

connected to adjacent structure

Method B

– One Level of Safety Mitigation

 Direct Component Bonding

– Structural Contact



## 7) Powered Fuel System Components within a T ank

- Single Point Ignition

Failure Protection

Method A

- One Level of Safety Mitigation

 Internal wire element conductors

– insulation jacket

Method B

- One 1 Level of Safety Mitigation

 Non conductive flexible outer cable sheath

Method C

- One Level of Safety Mitigation

 Component internal construction

– Electrical/ Fuel/ Vapor isolation

Method D

- One Level of Safety Mitigation

 Wire Conductor Shielding

Method E

- One Level of Safety Mitigation

 Transient Protection

– Solid State devices, example

- TransorbREPORT #:

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### APPENDIX B

Heat Transfer Analysis

– Impact of ACM Bleed Air Pipe on Auxiliary Fuel Tank

The following diagram represents the situation being analyzed:

The situation can be analyzed as a composite wall and represented as follows:

R 1

Δ T 1 R 2

Δ T 2 R 3

Δ T 3 R 4

Δ T 4 R 5

Δ T 5REPORT #:

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It is necessary t determine T6 to evaluate the potential inner surface temperature on the front spar.

Doing so will allow a fuel ignition risk assessment to be made as a result of the heat generated by the

ACM bleed air duct on the proximity of the fuel tank.

The analysis was conducted using the following assumptions:

1. An over

- temperature switch will stop the supply of bleed air should it exceed 560 ° F (567K)

therefore this is the maximum temperature that the volume will be subjected to. T ACM = 567K

2. The fuel will be in a heated state equal to the maximum temperature of the aircraft of 54 ° C

(317K) , T FUEL =317K

3. The local cross section (A) of 1m 2

4. k for air is 0.025 W/mK

∑ where

L is the local width of the section

k is the conduction coefficient of the material

R 1 = 1.847x10 - 5 K/W

R 2 = 0.305 K/W

R 3 = 3.814x10 - 6 K/W

R 4 = 0.864 K/W

R 5 = 1.375x10 - 5 K/W

R = 1.205 K/W

It is then required to determine the total energy transferred as heat (Q) through the section:

where = 259K

⁄

Therefore:

Since R 1 , R 3 and R 5 are very small, it is assumed that T 2 =T 1 , T 4 =T 3 & T 6 =T 5 and Δ T 1 = Δ T 3 = Δ T 5 = 0.

Δ T 2 = 215 W x 0.305 K/W = 66K

Δ T 4 = 215 W x 0.864 K/W = 186K

Therefore, T 6 = T ACM - Δ T 2 - Δ T 4 = 567 K

– 66K

– 186 K = 315 K or 126 ° F.REPORT #:

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Repeating this analysis for the scenario in which the over

- temperature switch should fail, it is assumed

that the maximum temperature that the duct could possibly see within normal operating conditions is

equal to the ITT MAX of 775 ° C(1427 ° F). Substituting T ACM with ITT MAX , results in a Q of 607 W.

ΔT2 = 606 W x 0.305 K/W = 185K

ΔT4 = 606 W x 0. 864 K/W = 5 2 4K

Therefore, T 6 = ITT MAX - Δ T 2 - Δ T 4 = 1048 K

– 185K

– 5 2 4 K = 33 9 K or 1 51 ° F.REPORT #:

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### APPENDIX C

Fault Tree Diagram for Auxiliary Fuel Tank