Federal Aviation 

Administration 

Memorandum 

Date: 

To: 

From: 

Subject: 

October 20, 2015 

FAA-2015-1621 

Part 23 Reorganization Rulemaking Project 

Lirio Liu, Director, Office of Rulemaking, ARM-Ic&-

Ex Parte meeting with EASA on the Airworthiness Standards for Normal, 

Utility, Acrobatic, and Commuter Category Airplanes (Part 23) rulemaking 

project 

On June I 0, 2015, a meeting was held between representatives of the European Aviation Safety 

Agency (EASA) and the Federal Aviation Administration (FAA) on the harmonization efforts of 

the reorganization of the FAA's Title 14 ofthe United States Code (14 CFR) Part 23 Notice of 

Proposed Rulemaking (NPRM) and EASA's Certification Specification (CS)- 23 Advance 

Notice ofProposed Amendment (A-NPA). 

Attending the meeting for EASA were Patrick Ky, Executive Director, and Lu Tygat, Director of 

Strategy and Safety Management. Attending the meeting for the FAA were Peggy Gilligan, 

Associate Administrator for Aviation Safety, Dorenda Baker, Director of the Aircraft 

Certification Service and Lirio Liu, Director of the Office ofRulemaking. 

On March 27,2015, EASA released the Advance Notice of Proposed Amendment (A-NPA) 

2015-06, titled "Reorganisation of Part 23 and CS-23". On May 27, 2015, the FAA submitted 

comments on the A-NPA. At the June meeting, the FAA made a general reference to those 

comments and a copy of those comments is attached. The FAA stated that there was general 

alignment with the philosophy expressed in the A-NPA and the FAA NPRM being drafted. 

The FAA stated that the anticipated publication date for the NPRM was in December 2015, and a 

Final Rule to be published in December 2017. These dates are consistent with the schedule 

posted on the U.S. Department ofTransportation's (DOT) Report on DOT Significant 

Rulemakings: http://www.transportation.gov/regul ations/report-on-signiticant-rul emakings. 

The FAA conveyed that the NPRM regulatory text contained in Subparts D and E was edited 

from the last version of the proposed regulations reviewed by EASA in November 2014, 

however the intent of the rule was not changed. The FAA and EASA agreed to discuss the 

changes proposed to the text to assure harmonization when the NPRM publishes for comment. 
2 

ATTACHMENT: FAA Comments to EASA A-NPA 

The FAA has some concerns with adding former guidance into the rule language specifically that 

is proposed CS 23.605 System and Equipment failure specifications. The goal of the FAA 

rewrite is "to streamline and simplify the approval process as well as provide for future 

flexibi lity" due to nevv technology and societies acceptable risk. Adding the minor, major, 

hazardous, and catastrophic table as well as codifYing the definitions of probability terms may be 

detrimental over the long term. 

The FAA suggested rewriting CS 23.605 as: 

CS 23.605 System and Equipment failure specifications 

(a) Each equipment and system identified in 23.600(b), considered separately and in relation 

to other aeroplane systems, is designed and installed so that there is a logical and 

acceptable inverse relationship between the average probability and the severity of fai lure 

condition effects. 

(b) Design each item of equipment, system, and installation, examined separately and 

in relation to other airplane systems such that-

( 1) The occurrence of any failure condition that would prevent the continued safe 

flight and landing of the airplane is extremely improbable; 

(2) The occunence of any failure condition that would significantly reduce the 

capability of the airplane or the ability of the crew to cope with adverse operating 

conditions is extremely remote; and 

(3) The occunence of any failure condition that would reduce the capability of the 

airplane or the ability of the crewmember to cope with the adverse operating 

conditions to the extent there would be a significant reduction in safety margin or 

functional capability is remote. 

(c) The severity of a failure condition is determined by the highest effect on aeroplane, 

occupants or crew