**Ap ril 27**  **, 2015**

**David Jensen Vice President, A** **ircraft Maintenance Aviation Consultants, Inc.**  **945 A irport Drive**  **San Luis Obispo, CA**

**93401 djensen@acijet.com** 
US Department of Transportation 1200 New Jersey Ave. SE West Building Ground Floor, Room W1 2
- 140 Washington, DC 20590
Submitted via: www.regulations.gov **Subject: Request**  **for Temporary**  **Exemption to CFR**  **1 35** 
**. 152**  **Parameter 5**  **" Normal** 

**Ac celeration**  **"** Dear Sir or Madam, It was brought to the attention of **Aviation Consultants, Inc.** Air Carrier Certificate N umber **W9BA 551H**  , by Bombardier Aerospace (BA) that certain Digital Flight Data Recorder (DFDR) systems certified and installed by BA on certain aircraft are not recording a specific parameter listed in 14 CFR 135 Appendix F

- "Airplane Flight Recorder Specification" to the full stated specifications listed for this specified parameter. Therefore, in anticipation of suitable rectification by BA , **Aviation Consultants, Inc.** is requesting exemption from the requirements of 14 CFR 135 Appendix F
- "Airplane Fligh t Recorder Specification", specifically "5. Normal Acceleration (Vertical)" only. This request applies to Bombardier Challenger CL

-600
-2B16 (CL

-604 Variant) m anufactured after August 1 8 , 200 0 and with a DFDR system installed p er Bombardier Aerospace SB604

- 31
- 010 operating under 14 CFR 135 by **Aviation Consultants, Inc.** domestically and abroad, currently **one (1)** affected aircraft **N529KF CL604 -** **5477**

.- 2
- April 28, 2015

**PETITION FOR EXEMPTION Specific Section and Extent of Relief Requested**  In accordance with 14 CFR 11 **Aviation C onsultants, Inc.,**  requests an exemption from the "5. Normal Acceleration (Vertical)" parameter requirements in Appendix F of 14 CFR 135.152 to permit sampling 5 times (0.2 seconds per sampling interval) per second until the Data Concentrator Unit (DCU), a subsystem of the affected DFDR system, is updated to provide 8 times per second (0.125 seconds per sampling interval) per second. **An exemption w**  **ill have no adverse impact on the safe operation of the aircraft** 
**.** The DFDR and its recorded parameters are not required for the safe operation of the aircraft. The DFDR's primary purpose is to support investigations in case of accidents. The affected Normal Acceleration parameter is provided through the DCU
**. Aviation**  **Consultants, Inc.** CL 604 variant aircraft has/have **2** DCU s. Except for the affected Normal Acceleration sampling rate, all data is being collected as required by 14 CFR 135 Appendix F (e.g. range

- 3g to +6g, resolution 0.004). The effect is that the normal acceleration parameter can be correlated to the appropriate recording rate, as described and illustrated below, with no substantive loss of information.

Given that the information can be effectively correlated with no substantive degradation in information, we respectfully submit that this compliance issue does not affect the safe- 3
- April 28, 2015

operation of the aircraft or hinder potential investigations requiring the DFDR data. Bombardier Aerospace has committed to developing an in
-service solution that involves a re -design of the D CU on or before September 2015 1

. Additionally Bombardier Aerospace has indicated that a subsequent fl eet retrofit period to account for parts availability and all affected operators downtime requirements, for a complete retrofit within two (2) years of the grant of the exemption. **Avi ation**  **Consultants, Inc.** is committed to working with Bombardier Aerospace to effect the final rectification to this issue concerning our affected aircraft as soon as practical. In many cases our affected aircraft are outside the United States for an extended pe riod. The public benefit and equivalent level of safety addressed below supporting this exemption request have equal applicability to **Aviation Consultants, Inc.** international flights. **The exemption is in the public interest**  The problem identified above wa s found by the aircraft manufacturer (Bombardier), and is a systems design problem which CL604 operators have no way to correct at this time. Granting this time limited exemption would be in the public interest because it would allow U.S. Part 135 operators the ability to continue to provide the unique services that support US public, business and industrial leaders while the aircraft manufacturer develops and certifies, and the affected CL604 operators incorporate , the modifications necessary to bring thes e aircraft into compliance. This request is substantially similar to the Exemption No. 11052 granted to Jet Solutions. L.L.C. in FAA Docket No. 2014

- 0542 on September 11, 2014. **Conditions and Implementation Aviation Consultants, Inc.**  requests that the FAA to allow continued operation of our aircraft subject to the conditions specified below: 1. This exemption is valid until the incorporation of the modification correcting the deficiency described herein or 24 months from the date of this exemption, whichever occurs first, unless p reviously superseded, rescinded or terminated by action of **Avi ation Consultants, Inc.**  2. Copies of this exemption to be retained by **Aviation Consultants, Inc.,** and the requirement that a copy be provided to the NTSB and FAA in connection with any accident or incident where DFDR data is requested or required to be provided; and- 4
- April 28, 2015

3. Wi thin **90** days of receipt of the Bombardier Aerospace Service Bulletin that rectifies the Normal Acceleration parameter issue; **Avi ation Consultants, Inc.**  must provide a schedule to its FAA CHDO principal avionics inspector (PAl), and/or persons designated by the FAA for completion of the new installation within the time period of this requested exemption.

**Federal Register Summary and Publication**  **Aviation Consultant s, Inc.,**  Air Carrier Certificate number **W9BA 551H,**  is requesting exemption from the requirements of 14 CFR Appendix F of 135.152 to permit the sampling rate of 5 times (0.2 seconds pe r sampling interval) per second 2 until Bombardier Aerospace issues a Servi ce Bulletin that corrects the issue, and in accordance with the conditions specified in this exemption request. This applies to all its CL604 aircraft used in operations under 14 CFR 135. **Aviation Consultants, Inc.**  also requests to utilize the exemption ou tside the United States. It is **Aviation Consultants, Inc.** ’s position that safety would not be jeopardized by issuance of this exemption as the DFDR is used solely as a recording device in accidents and incidents and the affected parameter will still provid e useful data in such cases. This exemption will benefit the public by allowing U.S. Part 135 operators the ability to continue to provide the unique services that support US public, business and industrial leaders while the aircraft manufacturer develops and certifies, and the affected CL604 operators incorporate, the modifications necessary to bring these aircraft into compliance. Due to the immediate and future impact and because this request does not establish new agency precedent as it is consistent wi th the scope of Exemption 11052 , **Aviation Consultants, Inc.**  requests a waiver to the 120 day filing requirements and the publishing of a summary of the petition in the Federal Register. If there are any questions, please do not hesitate to contact this of fice at any time. Thank you, David Jensen Vice President, Aircraft Maintenance 1 As indicated by Bombardier and based on the following: "The development schedule tak es into account current Bombardier and its suppliers resource capacities. The FAA is involved in some of the joint projects, including but not limited to the Challenger Avionics upgrade as well as Steep Approach certification and operational approval."