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FAA Mr Tom Rodriguez

EASA Mr Florentino Bascunana

0/REF: D0/TC 2741 /10 Toulouse, May 25t1 2010

SUBJECT: ATR 42 / 72 Petition for exemptions regarding 14 CFR sections

Dear Sir

This petition for exemption, submit to FAA, concerns:

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL

OPERATIONS

12. Amend Sec. 121.359 by revising paragraphs (e)(1) and (j)(1),

adding new paragraph (j)(4), and revising paragraph (k) to read as

follows:

Sec. 121.359 Cockpit voice recorders.*****

(k) All airplanes required by this part to have a cockpit voice

recorder and a flight data recorder, that install datalink

communication equipment on or after December 6, 2010, must record alldatalink messages as required by the certification rule applicable to

the airplane.

13. Amend appendix M to part 121 by revising footnote 18, to read as

follows:Appendix M to Part 121--Airplane Flight Recorder Specifications

*****

\18\ For all aircraft manufactured on or after December 6, 2010, the

seconds per sampling interval is 0.125. Each input must be recorded

at this rate. Alternately sampling inputs (interleaving) to meet

this sampling interval is prohibited.

Avions deTransport Regional. 1, allée Pierre-Nadot 31712 Blagnac Cedex - France

Phone: +33 (0)5 62 21 62 21 - Fax : ÷33 (0)5 62 21 68 00 -www.atraircraftcom
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12 Replace of SSFDR by a SSFDR with capability to acquire data at 512 words by second (present

equipment is limited to 256 words by second acquisition),

1.3 Modification of CMU/ACARS (which is only an option) computer to provide capability to transmit datalink

data,

1 .4 Replacement of SSCVR by a SSCVR having datalink recording capability,1 .5 Aircraft wiring modification to interconnect modified equipment to new equipment for datalink purpose.1 .6 Tests and certification of necessary modifications (MPC, CMU/ACARS, Wiring).

- Answering these two new requirements is basically planned in definition for models ATR 42-500 & 72-212A

with New Avionics Suite (Mod 5948).

- The aircraft definition for ATR 42-500 & 72-212A models with Current Avionics will be identical to present

definition, i.e. answering FAR 121.344 appendix M requirements (except for footnote 18), and not datalink

recording when ACARS installed so without any impact on safety.

Considering estimated transition plan for aircraft production in 2011 between aircraft with Current and NewAvionics, about 30 aircraft will be manufactured with Current Avionic Suite. And as ACARS is an option, no

more than 10 aircraft will be manufactured with this option.

Moreover part of these aircraft will not fly under FAA regulation, so estimated aircraft concerned flying underFAA regulation, or equivalent regulation followed by some other foreign Airworthiness Authorities, to be

manufactured in 2011 is between 5 and 10 aircraft for “Amend appendix M to part 121 by revising footnote 18”

and less than 5 aircraft for “Sec. 121.359 Cockpit voice recorders_Datalink”.

ATR Position:ATR position, regarding these requirements, is to request from FAA an exemption for ATR 42-500 & 72-212A

models with Current Avionics, considering that of course ATR will basically comply with these newrequirements for ATR 42-500 & 72-212A models with New Avionics Suite for which these requirements have

been taken into account in basic definition.

Summary (as requested in Federal Regulation Part 11.81):

ATR request an exemption for following requirements:

1 - Sec. 121.359 Cockpit voice recorders.

(k) All airplanes required by this part to have a cockpit voice

recorder and a flight data recorder, that install datalink

communication equipment on or after December 6, 2010, must record all

datalink messages as required by the certification rule applicable to

the airplane.

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We are at your disposal for any further information you may need to conduct your review.Yours faithfully,

Robert TROUILHET

Avionics Engineering Manager

AR

Jean Louis SOCCOL

ATR Office of Airworthiness

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