10-16-14

Martin Farrar

Director of Maintenance

Gama Charters Inc

700 Great Meadow Road

Stratford, CT 06615

Martin.Farrar@GamaAviation.com

US Department of Transportation

1200 New Jersey Ave. SE

West Building Ground Floor, Room W12-140

Washington, DC 20590

Submitted via: www.regulations.gov

Subject: Request for Temporary Exemption to CFR 135.152 Parameter 5 "Normal 

Acceleration"

Dear Sir or Madam,

It was brought to the attention of Gama Charters Inc Air Carrier Certificate Number 

O2GA970i, 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, Gama Charters Inc is 

requesting exemption from the requirements of 14 CFR 135 Appendix F - "Airplane 

Flight Recorder Specification", specifically "5. Normal Acceleration (Vertical)" only. This 

request applies to Bombardier Challenger CL-600-2B16 (CL-604 Variant) manufactured 

after August 18, 2000 and with a DFDR system installed per Bombardier Aerospace 

SB604-31-010 operating under 14 CFR 135 by Gama Charters Inc domestically and

abroad, currently (three) (N604VG sn5562, N848CC sn5660, N868CC sn5562)

affected aircraft.
- 2 - October 17, 2014

PETITION FOR EXEMPTION

Specific Section and Extent of Relief Requested

In accordance with 14 CFR 11 Gama Charters 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 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. Gama 

Charters Inc CL604 variant aircraft has/have 88 DCUs. 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.
- 3 - October 17, 2014

Bombardier Aerospace has committed to developing an in-service solution that involves 

a re-design of the DCU on or before September 20151. Additionally Bombardier 

Aerospace has indicated that a subsequent fleet 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. Gama Charters 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 

period. The public benefit and equivalent level of safety addressed below supporting 

this exemption request have equal applicability to Gama Charters Inc’s international 

flights.

The exemption is in the public interest

The problem identified above was 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 these 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

Gama Charters 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 previously superseded, rescinded or terminated by 

action of Gama Charters Inc

2. Copies of this exemption to be retained by Gama Charters 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

3. Within (90) days of receipt of the Bombardier Aerospace Service Bulletin that 

rectifies the Normal Acceleration parameter issue; Gama Charters Inc must 

1 As indicated 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."
- 4 - October 17, 2014

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

Gama Charters Inc, Air Carrier Certificate number O2GA970i, 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 second2until 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. Gama 

Charters Inc also requests to utilize the exemption outside the United States. It is 

Gama Charters 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 provide 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 with the scope of Exemption 11052, Gama 

Charters 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 office at any time.

2 Bombardier Aerospace tests and examination have shown that affected aircraft are sampling the "Normal 

Acceleration" parameter at this rate.