PAFI-RTP-001 Cold Flow Rev A.pdf

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Revision A Date: May 29, 2025

Low Temperature Flowability Test Plan

PAFI-RTP-001

PAFI Rig #1 Cold Flow Test

PAFI-RTP-001, Low Temperature Flowability Test Plan Rev A

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Revision Log:

Rev No.

Rev Date

Affected Page(s) Descript ion of Revision

New 10/1/20

Al l In i t ia l Release

A 5/29/25 General updates

PREFACE

This test plan specif ies the requirements for conducting comparative materials compatibi l i ty screening tests under the FAA’s piston aviation fuels init iat ive (PAFI). This document is derived from extensive FAA and industry experience and best pract ices for evaluat ing the suitabi l i ty of aviat ion fuels for use in the piston powered general aviat ion f leet. This document is used by the FAA to compare and evaluate new aviat ion fuels relat ive to the performance of 100LL aviation gasoline that meets ASTM D910.

In addit ion to the candidate unleaded fuel, an ASTM D910 fuel formulat ion is required for the screening tests under this plan.

This document is not intended to provide a method to obtain data to serve as a showing of compliance to regulatory requirements for the cert i f ication of aircraft or aircraft engines.

Furthermore, the material in this document does not change or permit deviations from exist ing regulatory requirements. This material is neither mandatory nor regulatory in nature. Use of this document or any derivative, in an attempt to obtain an FAA authorization of an al ternat ive aviation fuel, should be pre-coordinated and approved by the appropriate FAA off ice(s) as part of an approved qual i f icat ion program.

Successful completion of this test plan provides data that may support both FAA Fleet authorizat ion and development of an ASTM product ion specif ication for PAFI Fuels. I t also al lows the col lection of data to be used to generate performance and detonation performance values in support of other candidate fuel types being investigated under various FAA Research & Development projects.

References made to the Alternat ive Fuels Program Off ice or AFPO, refer to the group within the FAA that is responsible for the PAFI program. At the t ime of this revision, that group is the AIR-650 organization. Please see https:/ /www.faa.gov/about/ ini t iat ives/avgas/org_info .

https://www.faa.gov/about/initiatives/avgas/org_info

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TABLE OF CONTENTS

1. Scope

1.1. Provisos

2. Objectives

3. Background

4. PAFI Rig Screening Test Plans

5. Applicable FAA & ASTM Requirements

5.1. FAA Regulations

5.2. SAE Standards

5.3. ASTM Guidance & Practices

6. Applicable OEM Documents

7. Description of Test Articles

7.1. Flow Monitoring (all loops)

7.1.1. Flowmeter

7.1.2. Flow Display

7.2. RSA Loop

7.2.1. Diaphragm Fuel Pump

7.2.2. Idler Gear with Pump Cam

7.2.3. RSA Injection Servo

7.2.4. RSA Flow Divider

7.2.5. Air Bleed Fuel Nozzle

7.3. Continental Loop

7.3.1. High Pressure Fuel Pump Assembly

7.3.2. Throttle Body

7.3.3. Manifold and Injectors (Flow Divider)

7.4. Textron Loop

7.4.1. Electronic Fuel Pump

7.4.2. Fuel Selector Valve

7.5. Piper/Light GA Loop

7.5.1. Interrupter Fuel Pump with Integral Filer and Check Valve

7.5.2. Fuel Check Valve

7.5.3. Fuel Check Valve (#2)

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7.5.4. Shut Off / Selector Valve

7.5.5. Pressure Switch

7.6. Enstrom Loop

7.6.1. Shut Off / Selector Valve

7.6.2. Boost Pump

7.6.3. Fuel Strainer

7.7. Cirrus Loop

7.7.1. Fuel Selector Valve

7.7.2. Fuel Pump

7.7.3. Fuel Strainer

7.7.4. Flowmeter

7.7.5. Check Valve

8. Dukes P/N 366-00Definitions & Terminology

8.1. Calibration

8.2. Sample

8.3. Sample Set

8.4. Specimen

8.5. Validation

9. Conformity

9.1. Hardware

9.2. Test Fuels

9.3. Samples

10. Safety Procedures

10.1. Static Charge

10.1.1. Grounding (D4057, Section 5.4.1)

10.1.2. Personal Attire (D4057, Section 5.4.2)

10.2. Vapor Hazards

10.3. Ice Burns/Frostbite

10.4. Personal Protective Equipment

10.5. Low Temperature Exposure PPE –

11. Pre-Test Requirements

11.1. Test Stand Installation

11.1.1. Test Rig Construction

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11.1.2. Components

11.1.3. Fuel Lines

11.1.4. Air Lines

11.1.5. Fuel Tanks

11.1.6. Fuel Pump and Motor

11.1.7. Fuel Filters

11.2. Pre-Test Validation

11.2.1. Alternative Test Flow Rig Set Up

11.3. Pre-Test Inspections

11.4. Specimen Identification

11.5. Pre-Test Baseline Fuel Data

11.6. Laboratory Notebook

12. Test Facility & equipment

12.1. Temperature Controlled Environmental Chamber

12.2. Fuel Tanks and Fuel Conditioning

12.2.1. Fuel Tanks

12.2.2. Fuel Conditioning

12.3. Electronically Controlled and Monitored Component Control

12.4. Karl Fischer Moisture Meter – Coulometric

12.5. Instrument Calibration

13. Test Witnessing

14. Test Procedure

14.1. Materials

14.2. Test Preparation

14.2.1. Transfer Fuel

14.2.2. Ambient Water Content

14.2.3. Fuel Pressure and Flows

14.2.4. System Temperatures

14.2.5. Pump Speed, Voltage and Amperage

14.2.6. Air Pressure

14.2.7. RSA Injection Cycle Set-Up

14.2.8. Continental Injection Cycle Set-Up

14.2.9. Airframe Cycle Set-Up

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14.2.10. 140-micron finger screens

14.3. Data Collection

14.3.1. Fuel Pressure and Flows

14.3.2. System Temperatures

14.3.3. Pump Voltage, Amperage and Speed

14.3.4. Pneumatic System Pressure (RSA)

14.4. Cold Flow Test Preparation

14.4.1. Engine Loop Settings (Loops #1 (RSA) and #2 (Continental))

14.4.2. Airframe Loop Settings (Loops #3, #4, #5 and #6)

14.5. Cold Flow Test Execution for Injector Systems (Loops 1, and 2) – Baseline 100LL

14.5.1. Cycle 1

14.5.2. Cycle 2

14.5.3. Cycle 3

14.6. Candidate Fuel Preparation

14.6.1. Drain and Purge

14.6.2. Test Preparation

14.7. Cold Flow Test Execution – Candidate Fuel

14.8. Cold Flow Test Execution for Airframes (Loops 3, 4, 5, and 6) – Baseline 100LL

14.8.1. Cycle 1

14.8.2. Cycle 2

14.8.3. Cycle 3

14.9. Candidate Fuel Preparation

14.9.1. Drain and Purge

14.9.2. Test Preparation

14.10. Cold Flow Test Execution – Candidate Fuel

14.11. Test Conclusion

14.12. Data Collection

14.13. Post Test Measurements

14.14. Calculations

15. Pass/Fail Criteria

16. Test Personnel

17. Test Results Report

18. References

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TABLE OF APPENDICES

APPENDIX A – TEST FUEL COA REQUIREMENTS………..…....………………….. 46

APPENDIX B – INDIVIDUAL LOOP SCHEMATICS …………………………….…… 48

APPENDIX C – EXAMPLE DATA RECORD ………………………………………..… 57

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Rig Test Plan

PAFI-RTP-001

Low Temperature Flowability Test

1. SCOPE

This test plan specif ies the requirements and procedures for conducting comparative cold f low operabil i ty testing of an unleaded fuel to generate data required for part ic ipat ing in the FAA Piston Aviat ion Fuels Ini t iat ive (PAFI) test program.

This data wi l l be used for the evaluation of an unleaded fuel being tested in the PAFI test program.

Specif ic objectives of this comparative plan are def ined as fol lows:

1) Determine the acceptable performance of aircraft hardware when f lowed with an unleaded test fuel as compared to the performance when f lowed with an ASTM D910 compliant 100LL aviat ion gasol ine.

Specif ic performances to be evaluated include; deviation in f lows or pressure across def ined aircraft hardware, fai lure to actuate, plugging or other observed operation deviations.

The test plan includes the requirements for conf irming basel ine condit ion, test set-up, instrumentat ion, specimen col lection, and support ing documentat ion such as fuel cert i f icat ion documents as prerequisi tes to the test ing identi f ied.

Comparat ive low temperature f lowabil i ty tests between 100LL aviat ion gasoline (AvGas) and an unleaded test fuel are specif ied for hardware at cold soaked fuel temperatures of -20, -40, and -58 °C (-4, -40, -72 °F). During the testing, the hardware temperature may f luctuate with operations but the fuel shal l remain cooled to the target temperature for the durat ion of the test.

Specif ied aircraft hardware is representat ive of six typical aircraft design phi losophies, representing:

1) An RSA fuel injection system,

2) A Continental fuel injection system,

3) A Textron airframe system,

4) A Light General Aviat ion (GA) air frame system,

5) A Rotorcraft (hel icopter) airframe system, and

6) A Cirrus air frame system

Each test is performed by providing operation inputs of fuel f low and pressures representat ive of those experienced during a ful l f l ight prof i le. These six systems are designated as loops for convenience.

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Comparat ive cold f low testing consists of documenting the observed fuel f lows, pressures, and fuel pump speed, voltage, and amperage across representat ive hardware as the system is exercised over three- to four-hour f l ight profi les. Data col lected includes fuel pressure and fuel f lows at designated locat ions, and the speed, voltage, and amperage of fuel pumps, at specif ied t ime intervals.

Monitoring of the fuel temperatures at the fuel tank wi l l be performed for temperature control . Fuel samples are to be col lected and tested for water content by Karl Fischer per ASTM D6304 at specif ied temperatures, and base fuel surface tension at 25 °C, density, and viscosity at 0 and 25 °C and wi l l be reported. One way to measure the surface tension is per ASTM D1331, Method A. The kinematic viscosity may be measured by any ASTM standard including but not l imited to;

D445 Kinematic Viscosity, D7945 Derived Kinematic Viscosity, or D8092 Kinematic Viscosity Using a Microchannel Viscometer. The method used for determining surface tension and viscosity shal l be reported.

Requirements for conf irming hardware conf iguration, component health, test equipment, test instrumentat ion, and support ing documentat ion such as component and fuel cert i f icat ion are prerequisites to the testing ident i f ied.

1.1. PROVISOS

The fol lowing ident i f ies signif icant assumptions, requirements, and provisions associated with the testing prescribed within this test plan. Test ing performed pursuant to this test plan provides data support ing 1) FAA f leet authorization for PAFI unleaded fuels, and 2) the development of an ASTM Internat ional aviat ion gasoline production specif ication.

Al l the results of the testing performed and the associated data col lected under the fol lowing test plan are considered competit ion sensit ive and proprietary by the fuel offeror and are subject to NDA between the FAA and the Fuel Offeror.

Unlike a typical engine test and cert i f icat ion project, this test is using the engine and aircraft accessories as the test equipment; the fuel becomes the test art ic le.

I t is specif ied that the same physical r igs are used for both the D910 compliant 100LL AvGas and the unleaded test fuel. Al l components shall be purchased new and shall have al l necessary accompanying FAA compliant paperwork as part of the cert i f ication documentation.

NOTE : In the event test ing is conducted outside the FAA’s Wil l iam J. Hughes Technical Center, testing performed to this test plan may be witnessed by an identi f ied designated representat ive of the FAA. This may be achieved through the use of a Designated Engineering Representat ive (DER), or other representat ive approved by the AFPO or PAFI Advisory Committee prior to executing test ing.

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2. OBJECTIVES

The object ives of the PAFI comparative cold f lowabi l i ty tests are defined as fol lows .

1) Validate r ig performance with respect to fuel f lows and pressures using ASTM D910 compliant aviat ion gasoline at room temperature.

2) Flow each of the six individual loops on the baseline D910 100LL aviat ion gasoline at each of the three test temperatures per the provided test protocol. Repeat the f low testing on each loop using the unleaded test fuel at each of the three temperatures.

3) Measure and record the fuel pressure and f low, and any changes across the components at designated locat ions throughout the test cycles for each of the three temperature runs, on the baseline and proposed test fuel(s).

4) Collect and measure the moisture content of the fuel prior to the test start and after each of the three temperature runs, on al l fuels. For each fuel report the viscosity at a minimum of three temperatures, the density, and the surface tension.

5) Document and compare changes in fuel f lows and pressures across components.

3. BACKGROUND

Historical ly aviat ion gasoline has displayed a resistance to freezing and an observable stabi l i ty when cold soaked to temperatures as low as -58 °C (-72 °F).

This is pr imari ly due to the chemical composit ion of the fuel when produced in compliance with ASTM D910, a result of the original mil i tary requirements for the fuel to have a freezing point no higher than -60 °C (-76 °F). High al t i tude and arct ic condit ions can st i l l cold soak aircraft and ground fuel storage to these extreme low temperatures.

In order to blend fuels with the necessary detonation resistance without using lead (Pb), blending materials having dif ferent physical propert ies with respect to temperature could potential ly result in dif ferent operational performance when f lowed through aircraft hardware. Therefore, i t is desirable to conf irm the performance of hardware in the engine and airframe fuel systems at the lowest operating temperatures. This data is used in concert with the cold storage information developed in RTP-005 Freezer Testing to evaluate comparative cold temperature performance of the test fuel.

Because the chemical composit ion of the al ternative chemicals used to blend unleaded fuels may have dif ferent water saturation propert ies, di f ferent viscosity profi les, or di f ferent density profi les, i t is desirous to conf irm the performance of

11 | P a g e PAFI-RTP-001 the aircraft hardware at low temperatures. Impacts of concern include changes in fuel f lows, changes in fuel operating pressures, changes in pressure drops across f i l ters and valves, and degradation of the hardware components’ abi l i ty to operate.

These behaviors are the operational counterparts to viscosity, surface tension, freeze point and density. Addit ional ly, i t is necessary to confirm that fuel blend components do not separate at low temperatures.

During the original FAA PAFI test development, a ful l design activ i ty was undertaken to identi fy the representat ive components to be tested. The test developers began with aircraft l ikely to require greater octane fuel, represented by larger aircraft with high compression, large displacement engines, and continued through a design spiral to balance the desired aircraft/engine combinat ions, component avai labi l i ty, and cr i t ical data col lection requirements.

This resulted in the development of six representat ive r igs, referred to as ‘ loops’ and identi f ied for convenience by the representat ive manufacturer of each design phi losophy.

The FAA’s “ ideal” for a fuel component loop representing general aviat ion airframes was to mimic an aircraft such as the Piper Navajo or the Cessna 421 aircraft series. Ult imately, the procurement of new components for these aircraft was deemed problematic.

While developing the cold f low evaluation program, one of the challenges identi f ied as cr i t ical to the testing was access to new aircraft components. The use of remanufactured or overhauled components was init ial ly considered in order to improve component avai labi l i ty. The use of remanufactured or overhauled hardware was rejected based on concerns regarding potent ial variabi l i ty in condit ion between l ike part numbers. Furthermore, the exist ing supply chain requirement for submitt ing used parts (cores) in order to purchase new parts further prevented access to these remanufactured and overhauled components.

The di ff icul t ies in procuring suff icient components resulted in both the presented test loops, as wel l as the test protocol which runs both the baseline 100LL and the unleaded test fuel in the same hardware. The six loops developed during PAFI Phase 1 were:

1) RSA Loop

a. Components representat ive of the Lycoming RSA fuel injection system

2) Continental Loop

a. Components representative of the Continental Motors fuel injection system

3) Textron Loop

a. Components representat ive of the Textron airframe fuel system, single engine

4) Piper/Light GA Loop

a. Components representat ive of the Piper and other similar single engine, l ight general aviat ion air frame fuel systems

5) Enstrom Loop

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a. Components representative of the Enstrom and other piston powered rotorcraft airframe fuel systems

6) A Cirrus air frame system

a. Components representative of the Cirrus airframe fuel systems

4. PAFI RIG SCREENING TEST PLANS

The matrix of r ig screening test plans support ing the test protocols ident i f ied in TAC-PRJ-008 latest revision is presented as fol lows. The test plans fol low a common format with general procedures, processes, and test instrumentation being common to al l . The current plan is highl ighted in the l ist below:

RIG SCREENING TEST PLANS

PAFI-RTP-001, Cold Flow Hardware Test PAFI-RTP-002, Carburetor Ic ing Test (Incorporated into Engine Test Plan(s)) PAFI-RTP-003, Dynamic/Operat ional Hardware Test (Removed) PAFI-RTP-004, Long Term Storage Test, Ambient and Elevated PAFI-RTP-005, Cold Storage Stabi l i ty Test PAFI-RTP-006, Hot Surface Ignit ion Temperature Test, (Removed) PAFI-RTP-007, Ful l Scale Engine Emissions Test (Not Released) PAFI-RTP-008, Comingling Evaluation with 100LL (Not Released) PAFI-RTP-009, Dynamic Diaphragm Test PAFI-RTP-010, Fuel Sump Valve Test PAFI-RTP-011, Vented Drum Storage Test

Test plans prepared in support of the FAA PAFI test program for unleaded fuels are subject to the fol lowing review and approval protocol.

1) PAFI r ig test plans fol low a format and content consistent with establ ished practice for FAA compliance projects.

2) Draft test plans are furnished to the FAA AFPO off ice for review and approval pr ior to release to the TAC.

3) Upon concurrence from AFPO, the test plan is to be formally furnished to the PAFI TAC for review and concurrence preceded by FAA Contracts review and authorizat ion for release to the TAC.

4) A f inal test plan is to then be released, incorporating changes result ing from the TAC review.

5) Al l changes and referrals to this test plan should reference the latest revision level and date.

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5. APPLICABLE FAA & ASTM REQUIREMENTS

The fol lowing is a l ist ing of the applicable FAA and ASTM documents which contain information relevant to the test ing specif ied by this test plan.

5.1. FAA REGULATIONS

1) FAA Advisory Circular 33.19-1, “Guidance Material for 14 CFR §33.19 Durabil i ty for Reciprocat ing Engine Redesigned Parts”

2) FAA Advisory Circular AC33.4-1, “ Instructions for Continued Airworthiness”

3) FAA Order 8110.4C, “Type Cert i f icat ion Process”

5.2. SAE STANDARDS

There are no SAE standards applicable to the testing.

5.3. ASTM GUIDANCE & PRACTICES

ASTM guidance and standards applicable to the testing identi f ied are l isted as fol lows. Data provided by this test plan wi l l support development of an ASTM product ion specif ication for the unleaded fuel.

1) ASTM D6304 “Standard Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Addit ives by Coulometric Karl Fischer Titrat ion”

2) ASTM D7826-19a “Standard Guide for Evaluation of New Aviation Gasolines and New Aviation Gasoline Addit ives”

6. APPLICABLE OEM DOCUMENTS

No applicable OEM documents.

7. DESCRIPTION OF TEST ARTICLES

All of the fol lowing aircraft parts shal l be purchased new with al l appropriate FAA Form 8130-3 Airworthiness Approval tags. To faci l i tate procurement, each loop is presented below as i ts own subsection. None of the loops uti l ize an “in tank” boost pump per the FAA’s instruct ion.

Note: there are components with long lead-t imes and del ivery schedules of potential ly mult iple months. Purchase of new parts, as is required for this testing, is typical ly achieved through the use of distr ibutors. The abi l i ty to purchase parts from some industr ial faci l i t ies requires an industr ial account not typical ly avai lable

14 | P a g e PAFI-RTP-001 to individuals. Private access to parts through aftermarket distr ibutors supplying parts for amateur bui l t aircraft typical ly do not provide components with an FAA form 8130-3 tag. Components not having an 8130-3 tag, even where a vendor has described the part as new, are not permitted for this test. Overhauled or remanufactured parts are not acceptable.

The fol lowing l ist of recommended parts is comprised of hardware specif ical ly identi f ied and used during the original FAA PAFI testing. Any deviat ions from the fol lowing component l ist must be approved by the FAA AFPO representat ive prior to testing. Actual sourcing is at the discretion of the testing organization.

Note: Given the logist ics of parts procurement and the schedul ing of the cryogenic test chamber, i t is prudent to procure mult iples of components such as check valves and pumps. I f an issue arises during test ing, such as a leak, crack, part fai lure through no fault of the fuel, or other operat ional issue, parts may need to be swapped quickly to provide continuity of the test ing. In the event of a component change, enter a notation in the test logs regarding which part was swapped, when and why, and record this information in the f inal report. I f the fai lure occurs during a test cycle, the part is replaced and the ent ire cycle ( idle, 80%, and max f lows) must be repeated, from the start, for that fuel candidate on that loop. In most cases, i f fuel resources permit, the matching 100LL basel ine fuel test cycle should also be repeated to remove any question of cause of changes in performance after part replacement.

7.1. FLOW MONITORING (ALL LOOPS)

Determinat ion of the target “power”; idle, 80%, 100%, is determined by fuel f low, Wf. Fuel f low within the r ig is measured by the f low meter and monitored by the matching f low display. The f lowmeter given in 7.1.1 is a test component where an aircraft fuel f lowmeter is to be operated in the candidate fuel at the target temperatures. This f lowmeter may be used as the primary f low measuring device, or a separate industr ial or other redundant f low meter may be added to the loop i f greater accuracy or rel iabi l i ty is desired. Fuel f low is a cr i t ical component of this test so redundancy of fuel f low measurement is encouraged.

7.1.1. FLOWMETER

A turbine f lowmeter that is representat ive of a f lowmeter used on the aircraft to monitor fuel f low to the engine is required. The purpose of this f lowmeter is to monitor the fuel f low and is not a part of the compatibi l i ty evaluation.

The specif ied f lowmeter is the FLoScan 201A-6. The FLoScan 201A-6 f lowmeter used during the original PAFI testing has the fol lowing performance propert ies with gasoline.

• Flow range 0.3 to 30 gph

• K factor (pulses/gal lon @ 16 gph) -32,000

• Pressure drop 0.6 psi @ 15 gph

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2.4 psi @ 30 gph

• Working pressure 200 psi

• Temperature range -65/100 °C

• Bearing l i fe expectancy 10,000 hrs

• Electr ical Specif icat ions 12-15 VDC between + and – wires

30 – 50 mA @ 12 VDC This f low meter has since been superseded by an improved model, and specif ic FAA approval for the most recent type of turbine f lowmeter may need to be obtained as part of the test plan approval. A matching f low display is also required.

7.1.2. FLOW DISPLAY

The f low display used during the original test ing was matched to the turbine f low meter FLoScan 201A-6 referenced in Section 7.1.1. A f low display matched to the selected turbine f lowmeter is required and should be approved by the FAA with the f lowmeter.

7.2. RSA LOOP

The RSA loop includes the components used in an RSA fuel injection system.

7.2.1. DIAPHRAGM FUEL PUMP

Lycoming P/N 62B26931

7.2.2. IDLER GEAR WITH PUMP CAM

Lycoming P/N SL75072

Note that this component requires the entire idler gear assembly including pump cam, not just the idler gear.

7.2.3. RSA INJECTION SERVO

Precision Airmotive P/N 2549038-4-F (Note: the “F” indicates new unit)

7.2.4. RSA FLOW DIVIDER

Precision Airmotive P/N 2524232-2-F

7.2.5. AIR BLEED FUEL NOZZLE

Precision Airmotive P/N 2524846-2

7.3. CONTINENTAL LOOP

The Continental loop includes the components used in representative Continental Motors fuel injection systems.

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7.3.1. HIGH PRESSURE FUEL PUMP ASSEMBLY

Continental P/N 649368-60A4

7.3.2. THROTTLE BODY

Continental P/N 656785-1

7.3.3. MANIFOLD AND INJECTORS (FLOW DIVIDER)

Continental P/N 646433-12A4

7.4. TEXTRON LOOP

The Textron loop includes the components used in representat ive Textron airframe fuel systems.

7.4.1. ELECTRONIC FUEL PUMP

Cessna P/N 5100-00-4

7.4.2. FUEL SELECTOR VALVE

Cessna P/N 9851096-5

7.5. PIPER/LIGHT GA LOOP

The Piper / Light GA loop includes components used in representative Piper aircraft as well as high-use general aviat ion interrupter style pumps.

7.5.1. INTERRUPTER FUEL PUMP WITH INTEGRAL FILER AND CHECK VALVE

PMA Products Inc. P/N CA 35328-800

7.5.2. FUEL CHECK VALVE

The Andair Check valve specif ied is produced in the United Kingdom and is a complete closure check valve. This valve does not have a bleed hole. The cracking pressure is between 0.4 and 0.7 P.S.I .

Andair P/N CK375

7.5.3. FUEL CHECK VALVE (#2)

Beechcraft P/N 50-380170-11 (Used on the King Air)

7.5.4. SHUT OFF / SELECTOR VALVE

Allan P/N 6S122

Piper P/N 491-947

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7.5.5. PRESSURE SWITCH

Piper P/N 688-192

7.6. ENSTROM LOOP

The Enstrom loop includes components representat ive of the components used on piston powered rotorcraft .

7.6.1. SHUT OFF / SELECTOR VALVE

Enstrom P/N 280-12400-1

7.6.2. BOOST PUMP

Weldon P/N A10019-E; 28 Volt Fuel Pump

7.6.3. FUEL STRAINER

SigmaTek P/N G199-105-4; 40 µm part icle size with bypass valve and 30 P.S.I.

pressure test

7.7. CIRRUS LOOP

The Cirrus loop includes the components used in representat ive Cirrus airframe fuel systems. Cirrus parts are only avai lable from Cirrus.

7.7.1. FUEL SELECTOR VALVE

Cirrus P/N FS2520 – D204B

7.7.2. FUEL PUMP

Dukes P/N 5217-00-3

7.7.3. FUEL STRAINER

Cirrus P/N 14069-002

7.7.4. FLOWMETER

Cirrus uses an integral fuel f lowmeter. This f lowmeter is tested as a component but for commonali ty in the RTP-001 test data, this f lowmeter is not used to monitor the loop fuel f low.

Cirrus P/N 15415-002

7.7.5. CHECK VALVE

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8. DUKES P/N 366-00DEFINITIONS & TERMINOLOGY

Definit ions, terminology and abbreviations specif ic to this document and to FAA nomenclature are summarized in the fol lowing sect ion.

8.1. CALIBRATION

Calibration is a set of actions that establ ishes that the instrument which is being cal ibrated is equal to or reports values equal to a standard. The unknown, the instrument being cal ibrated, wi l l be checked against a known, the standard, at several dif ferent points, and adjustments made to the unknown to br ing i t into al ignment with the standard.

8.2. SAMPLE

Within this document the fol lowing concept is meant by the term “sample.” A sample is the specif ic material to be prepared as specimens and exposed to test f luids. For example, 100LL AvGas is a sample, and UL100 test fuel is a second sample.

8.3. SAMPLE SET

A sample set is al l of the individual specimens and al l of the test f luids comprising a set of samples to generate a set of data. For example, the pretest and posttest specimens from the 100LL and the pretest and posttest specimens from the UL100 experimental test fuel at -40 °F comprise the “-40 °F Sample Set.”

8.4. SPECIMEN

Within this document the fol lowing concept is meant by the term “specimen”.

Specimens are the individual pieces/al iquots col lected from the sample materials.

For example, the two individual fuel volumes col lected from the test sample (the fuel) are the test specimens for a single temperature test of the test fuel.

8.5. VALIDATION

As opposed to cal ibrat ion, val idation is the act of documenting that an instrument wi l l actual ly and consistently give expected results. This may be done by measuring a specimen with a known value and conf irming the instrument reports that value within the repeatabi l i ty of the instrument. I f the expected value does not result , val idat ion has fai led and some addit ional act ion must be taken to repair or adjust (cal ibrate) the instrument.

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9. CONFORMITY

9.1. HARDWARE

Confirmation that the hardware component test art icles conf iguration complies with the respect ive design data, bi l l of materials, and associated specif icat ions is a fundamental requirement. Hardware shall be establ ished as prescribed in the fol lowing sections on the basis of cert i f icates of compliance and cert i f icates of analysis.

Verif icat ion of test art icle conformance with specif icat ion shall be establ ished through the rel iance on FAA Form 8130-3, Cert i f icates of Conformance (CoC), and/or Cert i f icates of Analysis (CoA) which document that the hardware meets the intent of 14 CFR Part 21.33 Inspections and Tests, which states the fol lowing:

“(b) Each appl icant must make al l inspect ions and tests necessary to determine--

(1) Compliance wi th the appl icable ai rworth iness, a ircraf t noise, fuel vent ing, and exhaust emission requirements;

(2) That mater ia ls and products conform to the speci f icat ions in the type design;

(3) That parts of the products conform to the drawings in the type design; and

(4) That the manufactur ing processes, construct ion and assembly conform to those speci f ied in the type design”

The PAFI procedure for documenting the test hardware conform to specif ication is NOT a tradit ional FAA conformity process, but rather is a process that meets the intent “That materials and products conform to the specif icat ions….” through the use of CoC and CoA documentat ion.

9.2. TEST FUELS

Each PAFI test fuel shal l be shown to conform to the complete specif ication approved by the AFPO, as documented by a CoA furnished with each fuel batch or bulk volume del ivered by the fuel supplier to the test faci l i ty. In addit ion, representat ive data must be generated by an independent 3rd party laboratory for specif ic pre- and post-test cri ter ia. Pre-test samples should be from fuel col lected from the original shipping containers ‘as received’ by the Test Faci l i ty. Analysis must be performed on the fuel samples in accordance with Appendix A. Deviations from the fuel specif ication shal l require approval of AFPO. The ful l Test Fuel CoA as well as the pre and post-test analysis specif ied in Appendix A must be included in the test results report.

NOTE: A five-gal lon retained sample of the test fuel ‘as received’ at the test faci l i ty must be col lected and stored unt i l complet ion of the PAFI test program.

See PAFI-FHP-001.

NOTE: The impact of di f ferences in a fuel ’s propensity to draw water ( i ts hydrophil ic nature) and the potential for this water to freeze in the carburetor, is considered during Carburetor Icing testing and PAFI-RTP-005 Cold Storage test ing.

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9.3. SAMPLES

Each sample material shal l be shown to conform to i ts respective specif icat ion or qual i f icat ion as documented by a cert i f icate of qual i ty, cert i f icate of conformance, FAA form 8130, or other provided documentat ion. Samples comprised of mult iple pieces, sheets, or other units shal l be purchased from single lots. Where practical, samples shall be purchased in single units, i .e., a single length of hose, for preparat ion into specimens. Lot information, cert i f icates of qual i ty, cert i f icates of conformances, or other ident i fying documentation shall be included in the test results reports.

10. SAFETY PROCEDURES

This document does not purport to address al l safety considerat ions. This document does not replace or supersede individual instrument documentat ion, Federal, State, and local regulat ions, si te procedures, or general industry practices. Appropriate safety precautions are the responsibi l i ty of the Test Faci l i ty conducting the test. The Test Faci l i ty shal l establ ish and ensure compliance with al l appl icable safety and health standards. Prior to ini t iat ion of test, each test set-up shal l be inspected for safe practices. Consideration for personal protect ive gear (PPE) is the responsibi l i ty of the Test Faci l i ty.

10.1. STATIC CHARGE

10.1.1. GROUNDING (D4057, SECTION 5.4.1)

Fires and explosions have occurred as a result of hydrocarbon vapors being ignited by stat ic electr ici ty. I f electr ical charges are not grounded, they are unable to dissipate and become “stat ic.” This stat ic electr ic charge can accumulate and freely migrate to a single point on the sample container by a di fference in electr ical potential , then jump off as a high-energy spark discharge to a nearby less charged surface. The spark may be hot and prolonged enough to ignite nearby hydrocarbon vapors present above the lower explosive l imit (LEL). This potential shal l be managed by safely dissipating static charges, and through proper grounding, when handling f lammable products.

10.1.2. PERSONAL ATTIRE (D4057, SECTION 5.4.2)

Footwear or clothing, capable of causing sparks, for example, clothing made of synthetic materials, should not to be worn during fuel handling act ivi t ies in which f lammable vapors are l ikely to be present. Sampling should not be carr ied out during periods of atmospheric electr ic disturbance or hai l storms. To ground any stat ic charge on their body, the individual performing the handling should touch a grounded structure pr ior to handling fuel.

10.2. VAPOR HAZARDS

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All test ing must be done in compliance with Federal, State, and local s ite-specif ic f i re safety protocols as wel l as appl icable NFPA codes and standards.

10.3. ICE BURNS/FROSTBITE

This document does not replace or supersede any local or site requirements related to ul tra-low temperature exposure. Frostbi te or the formation of ice crystals in human t issues occurs at -4 °C (25 °F) or lower. This test requires cold soaking test art icles at temperatures from -10 to -58 °C (14 to -72 °F). The testing requires handl ing these chi l led samples at temperature and exposure to a chi l led environment (test chamber). Unprotected contact with i tems chi l led to less than -4 °C (25 °F) for periods of t ime longer than a few minutes can cause frostbi te and ice burns.

10.4. PERSONAL PROTECTIVE EQUIPMENT

This document does not replace or supersede any Federal, State, local or si te-specif ic requirements related to personal protect ive equipment. Proposed test fuels may be substantial ly dif ferent than tradit ional petroleum-based aviat ion gasoline. These test fuels should not be assumed to be equivalent in hazards to “gasol ine”.

1) Standard PPE – Technicians and test engineers are advised to famil iar ize themselves with the safety data sheets (SDS) for al l of the f luids under test.

Individuals are recommended to use at a minimum safety glasses or goggles, chemical resistant gloves as suited to the fuel chemistry, and lab coats or aprons. Note that f i re rated lab coats MAY NOT also be chemical resistant. Note that chemical laboratory coats may be a synthet ic material and may create stat ic electr ic sparks. Closed toed, non-charge isolat ing footwear is also recommended. The chemical propert ies of the test fuels may require gloves of dif fer ing levels of protect ion. For example, while ni tr i le gloves may suff ice for 100LL aviation gasoline, ni tr i le may not be suff icient for protect ion against other chemicals that may be in the test fuels. The test fuels may not yet have undergone hazard and toxicity testing in humans.

2) Component Run PPE – Technicians and test engineers must use appropriate hearing protection during test loop runs.

10.5. LOW TEMPERATURE EXPOSURE PPE –

Respect ive to the cold exposure, technicians and test engineers are advised to consider the necessary personal protect ive equipment specif ic to ultra-low temperature exposure. Examples of recommended PPE include but are not l imited to gloves with suff icient conductive protection to permit handling samples of -58 °C (-72 °F) for at least 30 minutes, a laboratory apron with insulative propert ies, and a face shield. These should be worn over standard laboratory PPE or i f

22 | P a g e PAFI-RTP-001 necessary, in a place of, recognizing the chemical resistance may be less than that of standard PPE.Liquid Nitrogen

This document does not replace or supersede local health and safety requirements for the handling and use of l iquid ni trogen (LN2). In l ieu of other requirements, safe handling of LN2 requires at a minimum the fol lowing.

1) Hand protection and goggles (not safety glasses) are to be worn when dispensing and handling l iquid nitrogen. When handling large quanti t ies, a ful l - length apron minimizes the chance of a spi l l going into shoes.

2) LN2 becomes gaseous nitrogen, and the nitrogen gas displaces oxygen in closed areas to the point where there is not suff icient oxygen to support l i fe. Ensure proper vent i lat ion is used in areas where LN2 can escape into the air . Cold ni trogen gas is heavier than air, so the r isk is greatest near the ground.

3) Do not store container(s) of LN2 in a cold room or any other locat ion where a person could physical ly enter an anoxic atmosphere. Cold rooms have no air changes and a person entering a room with elevated nitrogen in the air can quickly pass out and then die within several minutes of entering.

11. PRE-TEST REQUIREMENTS

This test plan has been developed based on the representat ive hardware of the six types of engines and airframes, and are designated as loops. These six loops;

1) RSA, 2) Continental , 3) Textron, 4) Piper / Light GA, 5) Rotorcraft, and 6) Cirrus; were used successful ly in previous low temperature f lowabil i ty tests and have been vetted by part icipating industry representat ives. This is one means of compliance to this test plan.

A test ing organizat ion may elect to use al ternative hardware or test cel l conf igurations. In the case al ternative means of compliance are selected, addit ional approval from the AFPO and potential ly aviat ion industry manufacturer representat ives wil l be required. Addit ional pre-test requirements are provided to val idate al ternative test cel l configurations are suff ic ient. This addit ional val idation:

1) Demonstrates the configurat ion can reach and maintain the test temperature with minimal temperature r ise from fuel tank inlet to test exi t . Fuel temperatures may r ise through a cycle but shal l return to the test temperature at the fuel tank.

2) Demonstrates the abi l i ty to rel iably provide fuel to the r ig at specif ied pressures and f lows, and to provide fuel f low and pressure measurements at specif ied locat ions during the test.

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3) Demonstrates that al l components actuate and operate as required throughout the ent ire test.

11.1. TEST STAND INSTALLATION

I t is permissible to construct test stands with the hardware from mult iple loops on a single physical stand to faci l i tate testing mult iple loops simultaneously. The instal lat ion of mult iple loops must be such that each test loop is ful ly self-contained including the fuel supply and fuel pumps.

While no attempt is made to control the component temperatures as the fuel f lows from the tank, through the components, and back to the tank during the testing, the temperature of the reservoir tank is to be control led. The temperature of the fuel leaving the reservoir tank and into the test loop must be maintained to the target temperature +/- 1 °C. Natural fuel heating may occur as the fuel passes through pumps and components, and while methods should be used to minimize this heat r ise, for example the use of an environmental chamber, the increasing fuel temperature is acceptable as the fuel passes through the component loop.

Once the fuel is returned to the reservoir, an LN2 heat exchanger is used to return the reservoir fuel to the target temperature. The ent ire stand shall be instal led in the environmental chamber to minimize temperature increases during testing. The actual fuel pumps and motors may be instal led such that they are located outside of the environmental chamber to minimize the pumps’ and motors’ contr ibutions to heat loads within the chamber.

11.1.1. TEST RIG CONSTRUCTION

Each of the six loop layouts are shown schematical ly in Appendix B. Rig construction shall comply with the individual schematics with respect to or ientation and directional f lows.

Figure 1 shows an example f low rig with two separate loops instal led on one cart.

Individual gauges are for pressure monitoring. Each of the two loops has a dedicated fuel tank in the rear. When the environmental chamber is closed, the fuel pumps and motors are outside of the chamber. (Note for purposes of clari ty in Figure 1, when instal led in this part icular chamber, the top shelf of the cart shown is sealed in the cryogenic chamber, and the bottom shelf with the motor and pumps is below and external to the cryogenic chamber.)

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Figure 1 - Example Rig Cart with Two Loops; Continental (left) and RSA (Right)

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Figure 2 - Example Rig Supply Fuel Tank

Figure 3 - Example Fuel Nozzle Installation

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Figure 4 - Example Fuel Pump Motor and Fuel Pump (Note: pressure gauges ahead and after pump)

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11.1.2. COMPONENTS

All components shal l be mounted in accordance with general ly accepted industry practices. Whi le not specif ical ly required, al l components should be mounted in a similar manner and orientat ion to those typical ly encountered in use. Mounting posit ions other than those encountered on the aircraft may introduce operational instabi l i t ies unrelated to the fuel under test.

Al l components shal l be instal led in compliance with the schematics provided in Appendix B. These schematics mimic the f low path of the represented loop and have the components in the order typical ly encountered in the aircraft . Caution is recommended with respect to the use of steel f i t t ings into aluminum components. Thermal expansion may cause cracking of the aluminum components even on tests as brief as the ones in this procedure.

Prior to the ini t ial test ing, the designated FAA representat ive shal l inspect the instal lat ion of the components in the test faci l i ty for conformance with the requirements and specif ications of this test plan. Conformance of faci l i ty instrumentat ion with cal ibration requirements may also be reviewed by the designated FAA representative.

11.1.3. FUEL LINES

Fuel l ines shall be standard aircraft r igid and f lexible fuel l ines. Rigid l ines for pr imary fuel f low are typical ly aluminum or stainless steel. Copper is not recommended for this test. Flexible l ines of aviat ion and aerospace qual i ty, should be verif ied to be cert i f ied to the temperatures of the tests, and l ike al l the components, should have FAA 8130-3 cert i f icat ion. Lines shall be f i t ted with appropriate AN f i t t ings for connect ion to the hardware components. Components shall be connected together by these fuel l ines in compliance with specif ied instal lat ion requirements, or with standard industry practices where no requirements are provided. Note, not al l of the ports on a component may be used. These ports may be capped/plugged.

11.1.4. AIR LINES

The use of Teflon™ (PTFE) tubing is recommended. Route l ines from a warm regulator to the RSA ram air pressure sensing port. Dry air or ni trogen gas must be used. Any moisture in the air sensing system causes ice blockages. Any air l ines or nitrogen l ines for the RSA ram air sensing should be purged with dry air or dry nitrogen for 5 minutes prior to the cold test. The RSA static air sensing port shal l be left open to the environment.

11.1.5. FUEL TANKS

Individual fuel tanks shall be used for each loop and for each fuel tested. Mult iple loops run simultaneously shall not use the same reservoir. In the event of a

28 | P a g e PAFI-RTP-001 problem with the fuel, a component, or the test apparatus, commingl ing of the fuels makes ident i f ication of the problem diff icul t or impossible.

Each tank must be capable of holding suff icient fuel to f i l l and run a test, typical ly eight (8) gal lons, and shall be instal led in a manner to permit cool ing of the fuel.

Too l i t t le fuel results in either the inabi l i ty of the LN2 heat exchanger to keep the fuel at the target temperature, or results in a stressing of the fuel as the fuel is re-cooled upon return to the reservoir. Repeated stressing of the fuel as i t is re-cooled can cause shock cool ing and cause some fuels to break down in a manner not typical of aircraft use. Cooling of the fuel should be accomplished by using a stainless-steel heat exchanger charged with LN2.

Al l fuel tanks are to be “gravity fed” from the reservoir and into the respect ive aircraft boost pumps or engine fuel pumps in the test loops. The fuel tank shal l maintain a head rise over the pump inlets of at least -0.75 to +1.0 psi regardless of the fuel f low. Higher gravi ty feed head pressures are permitted. To enhance pump priming, ensure the fuel level is at least 12 inches above the fuel pump inlet f i t t ing.

11.1.6. FUEL PUMP AND MOTOR

The aircraft boost pumps and the engine fuel pumps are used to provide fuel f low and pressure to the test loops. The aircraft boost pumps typical ly have an integral electr ic motor or drive; however, the engine pumps require an external mechanical or motor dr ive to actuate the pumps. These mechanical drives must mimic the engine accessory dr ive case in order to provide the proper pump RPM or pump actuat ion.

For both the RSA and the Continental loops, a separate f ixture to actuate the pumps in a manner repl icat ing the engine accessory case drive is required. Any number of drive f ixture designs is possible as long as the speed and range of motion of the pumps can be maintained. I t is recommended the pumps and the motors be located external to the environmental chamber to minimize heating the test components within the chamber. See paragraph 11.1.1 and Figure 1.

11.1.7. FUEL FILTERS

Because the test r ig is not equipped with fuel f i l ters, i t may be desirous to instal l standard 140 micron f inger f i l ters just in front of the fuel pump to protect the fuel pump from catastrophic part fai lure and concomitant debris. During original FAA test ing such a f i l ter could experience plugging due to ice formation unrelated to the test. I t can also be advantageous i f there is a quest ion regarding the test fuel, and troubleshooting of the fuel is required. In such a case, the f inger f i l ter should be removed, the removal for cause documented, and test ing resumed. While not required to run the test, the addit ion of these f inger screens can be invaluable i f anomalies occur during the cold test ing.

11.2. PRE-TEST VALIDATION

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Prior to data col lect ion test ing, each test f low r ig shal l be operated on a D910 compliant aviat ion gasoline to confirm operation, control , and data col lect ion.

This test is used to ident i fy any issues with the set-up prior to actual testing.

11.2.1. ALTERNATIVE TEST FLOW RIG SET UP

The fol lowing information is one means of compliance with the intent of the test ing.

I t is possible that other test layouts or individual components dif ferent from those presented here may be acceptable. Prior to the purchase of, instal lat ion, or r ig bui ld-up of al ternat ive means of compliance, the tester is required to procure approval from AFPO. Alternative instal lat ions or r ig bui ld-up requires val idation of correct operation of the instal led components on a D910 compliant 100LL. This val idation does not contr ibute to the test data. This val idat ion may be accomplished by demonstrat ing acceptable performance through an entire test cycle at each of -20, -40 and -58 °C.

11.3. PRE-TEST INSPECTIONS

Ensure al l components are new and where available have an appropriate FAA Form 8130-3 Cert i f icates of Conformance or other appropriate FAA documentat ion.

A logbook shall be maintained for the test with al l starts, stops, test t ime, total t ime, al l loop pressures, al l loop f lows, engine power sett ing being simulated (idle, 80%, or ful l power), system maintenance, and other notes logged as appropriate.

Anomalies, replacement parts, troubleshooting, and other unplanned events shal l be recorded in the log.

11.4. SPECIMEN IDENTIFICATION

I t is recommended that any vials/containers to be used to col lect specimens be marked with unique specimen identi f iers which are permanently aff ixed to the specimen vials. The selected means of marking must not interfere with the closure of the specimen vial , and must not be removed by accidental contact with the sample material . Marking that has proven problematic in previous test ing includes labeling the glass surface of the vial with permanent marker ( i .e. Sharpies™), as the test f luids including aviation gasoline removes the markings. The use of taped labels has been successful as long as the marks were made prior to sampling and the tape was placed on the vial prior to use. Other successful methods include the attachment of a pre-marked metal tag wired to the vial as long as the attaching wire is of a gage that does not interfere with the threaded cap.

11.5. PRE-TEST BASELINE FUEL DATA

Specimens in this test plan are comprised of l iquid fuels col lected from the unleaded test and the D910 100LL fuel tanks immediately before condit ioning the fuel and after a test run. A minimum of 50 ml shall be col lected into glass jars

30 | P a g e PAFI-RTP-001 with ei ther Tef lon l ined l ids or with a layer of foi l over the mouth. The specimen is col lected from fuel at the test temperature.