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October 3, 2012

US Department ofTransportation Docket Operations 

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### FRONTIER~ A whole different animal:

Frontier Airlines Inc. 7001 Tower Road Denver, CO 80249-7312

Reference: /A/ Exemption No.10611 from Raymond Towles Acting Director, Flight Standards Service Issued in Washington DC on August 28th 2012

Subject: FrontierAirlines Petition to utilize FAA Exemption 10611, FAR 121.344, Appendix Mto FAR 121.344, Parameter 68

..Brake Pressure (left and right)"

The rule requirementfrom which exemption is sought:

FrontierAirlines operating affected SA airplanes (Table 1) delivered afterAugust 19, 2002, herewith petitions for use of Exemption 10611; which extends relieffrom section 14 CFR part 121 with respecttothe sample interval of 121.344(f) parameter68. The exemption would applyto affected FrontierAirline aircraft ofthe specific configuration of A318/A319/A320 withoutthe bogie gear.

FrontierAirlines has been notified that Airbus discovered an inconsistency in its implementation of FAR 121.344 and related Appendix M.

The Airbus recording specification of SA airplanes 

### (A318/A319/A320)for parameter 68 is based on afull configuration of

### AIClanding gearswith 4 wheels on the main landing gear (wheels 1,2,3,4) and the availability of a so-called bogie landing gearwith 4 additional wheels (5,6,7,8). The normal brake pressure will be acquired from the Braking and Steering Control Unit (BSCU), whereby the sampling will be allocated to all wheels, representing the left and the right sides. The sampling ofthe normal brake pressure on individual wheels will be cycled each four seconds. The table below describesthe scheme of sampling within this 4-second period. If a bogie landing gear is not configured, then the parameter pairs 

### 5/7and 

### 618will be recorded as NCO (noncomputed data), which results in a gap of 2 seconds within the 4-second frame.

The petitioner requests relieffrom the following regulation: Section 121.344(f)(1) requires thatall turbine-engine-powered transport category airplanes manufactured afterAugust 19, 2002, record the parameters listed in paragraphs (a)(1) through (a)(88) ofthat section within the ranges, accuracies, resolutions, and recording intervals specified in Appendix M to part 121. Specifically,rror1t1er Alii**Hie~ A:Jo~;** **p,:,~~; P.;:).£v-Keque~ttur** **u~e** 01 c.xerriJ.JliUn**~uo~~** 

# FRONTIER.

A whole different animal:



### FrontierAirline is requesting relief from the sampling interval requirement for parameter 68 "Brake Pressure (left and right)" for the affected airplanes in Table (1) for a period of 24 months afterthe date ofthe exemption granted in Ref 

### I AI.

Grantofexemptionwould be inthe public interest:

The FAA has determined from the information provided that good cause exists for granting this exemption. However, as the aircraft manufacturerand not a U.S. operator, Airbus cannot be granted an exemption from U.S. operating requirements. Exemption from an operating rule can be granted onlyto affected operators. Since the 345 affected airplanes represent a significant portion ofthe U.S. fleet, it is in the public interestforthe FAA to allowthe continued operation ofthe airplanes subjectto certain conditions. Accordingly, the FAA will grantthe relief requested by Airbus to the operators ofthese airplanes when requested.



### The action to be taken bythe petitionerto provide a level ofsafetyequivalentto that provided bythe rule from which exemption issought orthe reason whya grantofexemptionwould notadverselyaffect publicsafety:

There are mitigations in place to assist accident investigators. In the eventof an accident investigation, the missing two seconds of brake pressure data can be partially reconstructed. During periods of normal brake pressure in manual brake mode, the two missing samples can be reconstructed with the datafrom parameter 69 "brake pedal application (left and right)." This reconstruction has limitations caused by the anti-skid function and differences between commanded and real pressure, however interpolation between the recorded samples ofthe main landing gear's four wheels is only possible in the auto mode scenario. The FAA finds that recording brake pressure (left and right), as described above, and using the suggested mitigation techniques temporarily provides an acceptable method for continued operation of the subject airplanes for a limited period oftime.



### Useofthe Exemption outsidethe United States:

FrontierAirlines would like to utilize the privileges ofthis exemption outside the United States. The scheduled operationsforthis model aircraft include international operations primarily in Mexico and Central America.

# FRONTIER.

A whole different animal:



### All MSN AJC Prod EngineType Model Registration type Date FFT 1803 A319 10-Sep-02 CFM56-585/P 319-111 N912FR FFT 1841 A319 13-Nov-02 CFM56-5B5/P 319-111 N914FR FFT 1860 A320 28-0ct-02 CFM56-584/P 320-214 N263AV FFT 1943 A319 26-Mar-03 CFM56-5B5/P 319-111 N918FR FFT 1980 A319 5-Jun-03 CFM56-585/P 319-111 N919FR FFT 1997 A319 30-Jun-03 CFM56-585/P 319-111 N920FR FFT 1939 A318 21-Jul-03 CFM56-5B8/P 318-111 N801FR FFT 1991 A318 30-Jul-03 CFM56-5B8/P 318-111 N802FR FFT 2012 A319 15-Aug-03 CFM56-585/P 319-111 N922FR FFT 2017 A318 12-Sep-03 CFM56-588/P 318-111 N803FR FFT 2010 A319 24-Sep-03 CFM56-585/P 319-111 N921FR FFT 2051 A318 22-0ct-03 CFM56-588/P 318-111 N804FR FFT 2019 A319 7-Nov-03 CFM56-585/P 319-111 N923FR FFT 2030 A319 5-Dec-03 CFM56-585/P 319-111 N924FR FFT 2103 A319 20-Feb-04 CFM56-5B5/P 319-111 N925FR FFT 2198 A319 5-Apr-04 CFM56-585/P 319-111 N926FR FFT 2209 A319 7-May-04 CFM56-5B5/P 319-111 N927FR FFT 2236 A319 3-Jun-04 CFM56-585/P 319-111 N928FR FFT 2240 A319 4-Jun-04 CFM56-585/P 319-111 N929FR FFT 2241 A319 8-Jun-04 CFM56-585/P 319-111 N930FR FFT 2253 A319 22-Jun-04 CFM56-5B5/P 319-111 N931 FA FFT 2258 A319 28-Jun-04 CFM56-5B5/P 319-111 N932FR FFT 2260 A319 6-Jul-04 CFM56-585/P 319-111 N933FR FFT 2287 A319 29-Sep-04 CFM56-585/P 319-111 N934FR FFT 2318 A319 22-0ct-04 CFM56-5B5/P 319-111 N935FR FFT 2325 A320 13-Dec-04 CFM56-5B4/P 320-214 N204FR FFT 2392 A319 8-Feb-05 CFM56-585/P 319-111 N936FR FFT 2400 A319 18-Feb-05 CFM56-585/P 319-111 N937FR FFT 2406 A319 1-Mar-05 CFM56-585/P 319-111 N938FR FFT 2448 A319 25-Apr-05 CFM56-5B5/P 319-111 N939FR FFT 2483 A319 14-Jun-05 CFM56-586/P 319-112 N941FR FFT 2518 A319 15-Jul-05 CFM56-5B6/P 319-112 N943FR FFT 2751 A319 21-Apr-06 CFM56-5B5/P 319-111 N945FR FFT 2806 A319 22-Jun-06 CFM56-585/P 319-111 N947FR FFT 2836 A319 20-Jul-06 CFM56-586/P 319-112 N948FR FFT 2857 A319 17-Aug-06 CFM56-5B6/P 319-112 N949FR FFT 3389 A320 7-Feb-08 CFM56-584/3 320-214 N201FR FFT 3431 A320 6-Mar-08 CFM56-584/3 320-214 N202FR FFT 4127 A319 9-Dec-09 CFM56-5B6/3 319-112 N951FR FFT 4204 A319 24-Feb-10 CFM56-586/3 319-112 N952FR FFT 4254 A319 29-Mar-10 CFM56-5B6/3 319-112 N953FR FFT 4253 A320 30-Mar-10 CFM56-5B4/3 320-214 N205FR FFT 4272 A320 27-Apr-10 CFM56-584/3 320-214 N206FR FFT 4307 A320 11-May-10 CFM56-584/3 320-214 N207FR

Table (1)