From: Wayne Sprigg <wsprigg@fieldav.com>

To: Victor Wicklund/ANM/FAA@FAA

Date: 09/27/2012 02:03 PM

Subject: RE: Petition for Exemption, Auxiliary Fuel Tanks for DHC-8 (Docket FAA-2012-0585)

Mr. Wicklund

The interpretation of the standard is what I believe is causing the problem.

It is our belief that the desire of the FAA within a fuel system design is to achieve 3 levels of

safety mitigation for the potential effects of HIRF, Indirect Effects of Lightning and Single Point 

Ignition for those fuel system components/elements that are powered.

The text that follows lists the components where full compliance may not be demonstrated.

(Ref. Appendix A Safety Assessment Document 25370105, previously supplied )

Appendix A - Items 3 and 4 – (Magna stick)

Non Compliance Design Element

HIRF – only 2 Levels of safety Mitigation achieved.

Indirect Effects of Lightning – only 1 level of mitigation achieved.

Requirements for Compliance

Due to the design of this type of vendor item full compliance is not achievable.

Practicality

Compliant components of this type are not available.

Appendix A - Items 5 and 6 – (Valve – Aux Tank Drain)

Non Compliance Design Element

HIRF – only 2 Levels of safety Mitigation achieved.

Indirect Effects of Lightning – only 1 level of mitigation achieved.

Requirements for Compliance

Due to the design of this type of vendor item full compliance is not achievable.

Practicality

Compliant components of this type are not available.

Appendix A - Items 7 and 8 – (Upper Fuel Float Switch – Transfer System)

Non Compliance Design Element
Component cannot be electrically bonded to structure.

Indirect Effects of Lightning – only 2 levels of mitigation achieved.

Requirements for Compliance

Due to design of component outer casing (anodized surface) direct component bonding not achievable.

Practicality

Compliant components of this type are not available.

Anodized casing surface required to prevent corrosion effects when immersed in fuel.

Appendix A - Items 9 ,10, 11 , 12 – (Fuel Probe)

Non Compliance Design Element

Component cannot be electrically bonded to structure.

Indirect Effects of Lightning – only 2 levels of mitigation achieved.

Single Point Ignition – only 2 levels of mitigation achieved.

Requirements for Compliance

Due to design of component (Capacitive Sensor) the probe must be isolated from aircraft structure.

Therefore electrical bonding of the casing is not possible.

Practicality

Compliant components of this type are not available.

Operationally the casing of the probe must be isolated from aircraft structure.

Appendix A - Items 20, 21, 22, 23 – (Check Valve)

Non Compliance Design Element

Component cannot be electrically bonded to structure.

Note 

Fuel lines connecting to this component have 3 independent electrical bonding paths.

Requirements for Compliance

Due to design of component outer casing (anodized surface) direct component bonding not achievable

Practicality

Compliant components of this type are not available

Anodized casing surface required to prevent corrosion effects when immersed in fuel

Appendix A - Items 30 and 31 – (Solenoid Valve – pre-check Valve)

Non Compliance Design Element

Component cannot be electrically bonded to structure.
Note 

Fuel lines connecting to this component have 3 independent electrical bonding paths.

Requirements for Compliance

Due to design of component outer casing (anodized surface) direct component bonding not achievable.

Practicality

Compliant components of this type are not available.

Anodized casing surface required to prevent corrosion effects when immersed in fuel.

Appendix A - Items 34, 35, 36, 37 – (Pressure Switch – Transfer System)

Non Compliance Design Element

Component cannot be electrically bonded to structure.

Note 

Fuel lines connecting to this component have 3 independent electrical bonding paths.

Requirements for Compliance

Due to design of component outer casing (anodized surface) direct component bonding not achievable.

Practicality

Compliant components of this type are not available.

Anodized casing surface required to prevent corrosion effects when immersed in fuel.

Appendix A - Items 38 and 39 – (Fuel Float Switch – Refuel/Defuel)

Non Compliance Design Element

Component cannot be electrically bonded to structure.

Indirect Effects of Lightning – only 2 levels of mitigation achieved.

Requirements for Compliance

Due to design of component outer casing (anodized surface) direct component bonding not achievable.

Practicality

Compliant components of this type are not available

Anodized casing surface required to prevent corrosion effects when immersed in fuel.

Regards

Wayne

From: Victor.Wicklund@faa.gov [mailto:Victor.Wicklund@faa.gov] 

Sent: Tuesday, September 18, 2012 4:27 PM

To: Wayne Sprigg
Cc: Michael.Collins@faa.gov

Subject: RE: Petition for Exemption, Auxiliary Fuel Tanks for DHC-8 (Docket FAA-2012-0585)

Mr. Sprigg,

Thanks for your note. We are reviewing the latest information you've provided and will provide a formal 

response in October. Based on a cursory review of your data and your request, I'm having trouble 

determining (1) what specific aspects of your design do not comply with § 25.981, (2) specifically what 

you have determined it would take to comply for those aspects, and (3) why it is not practical to 

incorporate those specific features. This is the level of detail you must provide and we must assess as 

we determine whether to grant the exemption you seek as explained in FAA Policy Memorandum 

ANM-112-08-002. 

I'm providing a link to the public docket associated with the exemption we granted to Boeing on the 

subject, so that you can see the specific questions we are likely to provide to you and the level of detail 

you will need to provide in response.

http://www.regulations.gov/#!documentDetail;D=FAA-2009-1058-0005

If you believe I've overlooked something, and that you've provided this information, please let me know.

Best regards, 

Victor Wicklund

Manager, Propulsion & Mechanical Systems, ANM-112

FAA Transport Airplane Directorate Standards Staff

Phone 425-227-2192

We value your feedback. Click here to send us your feedback.

From: Wayne Sprigg <wsprigg@fieldav.com>

To: Victor Wicklund/ANM/FAA@FAA

Cc: "'mike.collins@faa.gov'" <mike.collins@faa.gov>

Date: 09/18/2012 06:21 AM

Subject: RE: AUTO: Victor Wicklund/ANM/FAA is out of the office (returning 08/20/2012)

Mr. Wicklund

I would like to inquire of the status of the petition for exemption for the

Auxiliary Fuel Tank Installation DHC-8 Series Aircraft, FAA Docket 

Reference FAA-2012-0585.

The original petition was submitted May 29th, which resulted in an FAA letter of 

clarification request which was received by me on or about July 24th, 2012. 

This in turn resulted in Field Aviation providing a revised submission which 

included the requested additional information. This was sent by E-Mail 

attachment to your attention August 08th, 2012.
Would you please indicate what the current status of the petition is?

Our U.S. customer for this system is Sierra Nevada Corporation.

Regards

Wayne

Wayne T. Sprigg

Director DAO and Flight Test 

Field Aviation 

2450 Derry Rd. E., Hangar 2

Mississauga, Ontario, Canada L5S 1B2 

Phone: +1 905 676 1540 Ext. # 264

Fax: +1 905 676 1143

Mobile: +

Email: wsprigg@fieldav.com

www.fieldav.com

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