Ace Aviation Services Corporation

FAA Certificate Number V6NA918J

5525 NW 15th Ave., Suite 150 ● Fort Lauderdale Executive Airport ● Fort Lauderdale, Florida 33309

800-556-6633 ● 954-771-5779 ● Fax: 954-772-6981 ● www.hopajet.com

September 11, 2014

To: FAA Flight Standards District Office

FSDO # 19

2895 SW 145th Avenue

Suite 120

Miramar, FL 33027

ATTN: Gary Justice

Principal Avionics Inspector

From: Tim Rounds

Assistant Director of Maintenance

Dear Gary,

It was brought to the attention of Ace Aviation Services, Corporation Air Carrier Certificate Number V6NA918J, by 

Bombardier Aerospace (BA) that certain Digital Flight Data Recorder (DFDR) systems certified and installed by BA are 

not recording a specific parameter as listed in 14 CFR 135 Appendix F - "Airplane Flight Recorder Specification" to the 

full stated specifications listed for this specified parameter. This notification was through BA Advisory Wire AW600-31-

2456 dated 9-4-2014.

Therefore, in anticipation of suitable rectification by Bombardier Aerospace, Ace Aviation Services, Corporation is 

requesting exemption from the requirements of 14 CFR 135 Appendix F - "Airplane Flight Recorder Specification", 

specifically "5. Normal Acceleration (Vertical)" only. This applies to all Bombardier Challenger CL- 600-2B16 (CL-604 

Variant) with a DFDR system certified and installed by Bombardier Aerospace during aircraft production or incorporation 

of Service Bulletin 604-31-005 and/or 604-31-010. This applies to all CL-604 aircraft used in 14 CFR 135 operations by 

Ace Aviation Services, Corporation domestically and abroad, currently two (2) affected aircraft.
PETITION FOR EXEMPTION

Specific Section and Extent of Relief Requested

In accordance with 14 CFR 14 Ace Aviation Services, Corporation requests an exemption from the "5. Normal

Acceleration (Vertical)" 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 will 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. Ace Aviation Services, Corporation CL604 

variant aircraft 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 operation of the aircraft or hinder potential investigations 

requiring the DFDR data.

Bombardier Aerospace has committed to us they are developing an in-service solution with Rockwell Collins, that 

involves a re-design of the DCU on or before September 2015. Additionally Bombardier Aerospace has indicated to us 

that the subsequent fleet retrofit period (minimum 85 aircraft affected) will take at least two years after of the re-design. 

Ace Aviation Services, Corporation is committed to working with Bombardier Aerospace to effect the final rectification 

to this issue concerning our affected aircraft as soon as practical.

The exemption is in the public interest

Granting of this exemption will prevent the need to have the affected aircraft interior passenger seating reconfigured and 

recertified (via STC) for 9 seats with the ensuing risks and downtime associated with moving the aircraft and cr ews to 

locations were this can be accomplished or restricting the utilization of the aircraft to 14 CFR 91 operations only, both of 

which could hinder Ace Aviation Corporation’s ability to provide a continued high level of safety and service to its 

current and future customers.
Conditions and Implementation

Ace Aviation Services, Corporation requests that the FAA allow continued operation of our aircraft subject to the 

conditions specified below :

1. Requirement that Ace Aviation Services, Corporation will submit to the FAA its intention to use this exemption, 

if given, for all its affected aircraft and acknowledgement of the conditions contained in the exemption and basis 

for continued operation within a specified time of not more than 30 days of the issuance of this requested 

exemption.

a. As indicated to Ace Aviation Services, Corporation by Bombardier and based on the following: "The 

development schedule takes 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.

2. Copies of this exemption to be retained by Ace Aviation Services, Corporation 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

3. Within 90 days of receipt of the Bombardier Aerospace Service Bulletin that rectifies the Normal Acceleration 

parameter issue, Ace Aviation Services, Corporation must provide a schedule to its FAA CHDO principal 

avionics inspector (PAI), 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

Ace Aviation Services, Corporation, Air Carrier Certificate number V6NA918J, 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 per sampling interval) 

per second 2 until Bombardier Aerospace issues a Service 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. Ace Aviation Services, Corporation also requests to utilize the exemption outside the United States.

It is Ace Aviation Services, Corporation’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 provide 

useful data in such cases. This exemption will benefit the public by preventing the movement of aircraft and flight crews 

with associated risks, to a place where the interior configuration may be modified, and ensuring affected aircraft are 

continued to operate under 14 CFR 135, in lieu of 14 CFR 91 operations only, thus maintaining the same level of safety 

and service to both current and future customers.

Due to the immediate and future impact, Ace Aviation Services, Corporation 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 office at any time

Sincerely,

Timothy F. Rounds

Assistant Director of Maintenance, Ace Aviation Services, Corporation

Cc: Mr. Gary Justice – PAI South Florida FSDO 19

Ms. Jaunita Corbin – PMI South Florida FSDO 19

Mr. Barry Ellis – President / Director of Operations Ace Aviation Services, Corporation

Mr. Curtis Yeagle – Director of Maintenance – Ace Aviation Services Corporation

Mr. Wayne Modny – Director of Quality Control – Ace Aviation Services, Corporation