u.s. Department of Transportation 

### Federal Aviation Administration


# JUN 1 4 10Gl

Mr. Craig Bolt AssistantChair TransportAirplane and Engine Issues Group Aviation RulemakingAdvisory Committee Pratt & 

## Whitney 400 Main St. E. Hartford, CT06108

DearMr. Bolt:

This letteris a follow-up to myletterto you ofJanuary 26, 2005. 

## In that letter we promised to identify the alternative actionsto the Aviation Rulemaking Advisory Committee CARAe) recommendationsthatwere notlisted in our Regulatory Program Review. Those alternative actionsare onthe attached list. If

## youhave any question on the actions on this list please contactMr. BrianA. 

## Yanez at 202-267-5864.

Once again we value yourcomments on howwe address ARAC recommendations. We appreciate your supportin developingtheserecommendations.

Sincerely,

John 1. 

## Hickey Director, Aircraft Certification Service

# AVS "Do 

# ByOther Means" Projects Follow-Up

ProjectTitle "Other Means"

Certification of New Propulsion Technologies Currently, FAA is able to offerairworthiness requirements forthese technologies via Special Conditions. Industry is in agreementwith this 

### on Part 23 Airplanes 

### aoproach. We have linked this rulemaking effortwith the Part 135Aviation
Jetand High Performance Part23 Airplanes Rulemaking Committee (ARC). Until thiswork is completed, FAA will continue the use of Special Conditions to establish airworthiness 

### renuirements for the lanes. Standardization of Improved Small Airplane This rule ties In with the spin resistance ofairplanes_ This rule would not Normal Category Stall Characteristics be relieving in nature. This rulemaking will proceed when rulemaking Requirements (23.777, 23.781, 23.1141, 23.1309,23.1337,23.1305\ resources become available. (Beta) Reverse Thrust and Propeller Pitch The JAA and EASA have adopted this rule into change 16 of the JAR and Settings Below the Flight Regime (NPRM), CS-25, respectively. The FAAwill recategorize this project as enveloping 25.1155 rulemakinq. Since the ARAC HWG was unable to reach agreement on an acceptable Bird Strike rule revision, the FAA does not plan to implement this project through "other means". ThisARAC recommendation may be voluntarily used as a basis for an Casting Factors, 25.621 equivalent level ofsafetyfinding**reql~~.st** (per Transport Airplane Directorate nolicv memo dated 1/4/01

. ThisARAC recommendation will continue to be applied to new certification Fast Track Harmonization Project: Engine and projects as a Special Condition (the size, configuration and failure modes APU Loads Conditions, 

### 25.3611.362 (ARAC) ofjet engines has changed considerablyfrom those envisioned when the oriainal enoine seizure rule was first adootedl.
Fire Protection of Engine Cowling, ThisARAC recommendation may be voluntarily used as a basis foran equivalent level ofsafetyfinding request (perTransportAirplane 25.1193(e)(3) (NPRM) Directorate oolicv memo dated 114/01 

### I. ThisARAC recommendation will be removedfrom the Do By Other Means Flight Loads Validation (ARAC), 25.301 category because the recommendation onlycontained a draft AC (no rulemakino\. There IS no ARAC recommendation associated with this projectas the Fuel Vent System Fire Protection tasking waswithdrawn bythe FAAon 

### 6/15/04. Since the FAA will not be

- Retrofit Rule for Part 121, 125, and 135 Only pursuing an operational rule, asoriginally planned, we will continue to (Final) issue ADs, as appropriate, to address existing fleet issues. The FAAwill

- Part 25 Rule also prevent**certificatio~~~** an unsafe design feature/characteristic using the p'rovisions of21.21(b (21- The JAAand EASA have adopted this rule into change 16ofthe JAR and Ground Gust Conditions (RPR), 25.415 CS-25, respectively. The FAA will recategorize this project as enveloping rulemakino. Harmonization ofAirworthiness Standards The JAAand EASA have adopted this rule into change 16ofthe JAR and Flight Rules, Static Lateral-Directional CS-25, respectively. The FAAwill recategorlze this project as enveloping Stability, and Speed Increase and Recovery Characteristics'(NPRM\,25.177 rulemaking.

Use ofAC 20-135 to demonstratefireproof and fire resistant Harmonization of Part 1 Definitions Firep"oof characteristics results in an adequate level of safety. Forcases whereAC and Fire Resistant (RPR) 20-135 is used as a method ofcompliance, the FAAwould not need to use the provisions of21.21(b)(2).
Loads and Dynamics

- Continuous This ARAC recommendation may be voluntarily used as a basisforan equivalent level of safetyfinding request (perTransportAirplane Turbulence Loads, 25.341(b) Directorate DOlicv memo dated 1141011.For future certification projects, the FAA plans to revise the eXisting Issue
Restart Capability (ARAC) Paper, based on the ARAC recommendation, to prevent certification ofan unsafe feature/characteristiC under the provisions of section 21.21(b)(2).

The portion ofthe ARAC recommendation related to a lack ofATTCS onoffswitch and performance credit with reduced take-off thrust, may be voluntarily used as a basis for an equivalent level of salety finding request
Automatic Takeoff Thrust Control System (per Transport Airplane Directorate policy memo dated 

### 114/01), The portion ofthe ARAC recommendation concerning <lddltionai (ATTCS), 25.904, App I certification requirements for go-arounds may be applied to new projects
as a SpeCial Condition (Hle onginal rules related to ATTCS did not consider performance creditforgo-around conditions).

The references to 25,855 and 25 857 should not be associated with this project and will be removed. The FAA does have a rulemaklng project associated with the ARAC recommendation for 25.855 and 25,857 (Class Cargo Compartment Fire Exlingulshlflg or B and Class F cargo compartments). The ARAC recommendation associated with 25.851 (b) may be voluntarily used Suppression Systems, 25,851 (b), 25.855, as a basis for an equivalent level of safetyfinding request (perTransport 25.857 Airplane Directorate poliCy memo dated 1/4/01). The AC material associated with thatARAC recommendation would also be considered a method of direct compliance with the existing 25.851(b},

ThiS ARAC recommendation may be voluntarily used as a basis for an Proofof Structure, 25,307 equivalent level of safetyfinding request (per Transport Airptane Directorate poliCY memo dated 1/4/011. Since the ARAC HWGwas unable to reach agreement on an acceptable rule rev'lsion, the FAA does not plan to implement this projectthrough High Altitude Flight 25.365(d) "other means". However, the FAA Interim policy proVides gUidance for requesting an exemption until a final rule IS adopted.

Damage-Tolerance and Fatigue Evaluation of This ARAC recommendation may be voluntarily used as a basis for an equivalent level ofsafetyfinding mquest (perTra'lsportAirplane Structure, 25.571 Directorate policv memo dated 114/011. This ARAC recommendation will be removed from the Do By Other Means Material Properties, 25.603 category because the recommendation only contained a draft AC (no rulemakinq1. Fire Protection 33,17 See Note 1Below Rotor Integrit Overs eed 33.27 See Note 1 Below Safet Anal SIS 33,75 See Note 1 Below Rotor Integrity

- Over-torque 33.84 See Note 1 Below 2**Minute/3~** Second One Engine Inoperative See Note 1 Below OEI) (33XX)

- Electrical and Electronic Engine Control See Note 1 Below S stems (33.28)

Note 1: EASA CS-E certification specification can be vuluntarily used as an alternate to the corresponding 14 CFR Part 33 requirements under a 14 CFR 

### § 21.29(a){1)(Ii) eqUivalent levet of safety frndlng However, it will be necessaryforthe E&PD to review each projecton a case-by-case basis to
ensure that there are no unique Circumstances thatwoutd invalidate the acceptabilityofthis approach. If this approach IS accepted by the E&PD, the corresponding CS-E specification must be used in it's entirety.