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October 3, 2012 

US Department of Transportation 

Docket Operations 

:JEPARTMENT OF 

; :iANSPORTATION . ,-,r;<c"'" npER 0. ~ ·-''-"'~I u ,]ATl I~S 

lOll OCT -<i P 1: 4CJ 

West Building Ground Floor, Room W12-140 

1200 New Jersey Ave, SE 

Washington, DC 20590 

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: Frontier Airlines Petition to utilize FAA Exemption 10611, FAR 

121.344, Appendix M to FAR 121.344, Parameter 68 .. Brake 

Pressure (left and right)" 

The rule requirement from which exemption is sought: 

Frontier Airlines operating affected SA airplanes (Table 1) delivered after August 19, 

2002, herewith petitions for use of Exemption 10611; which extends relief from section 

14 CFR part 121 with respect to the sample interval of 121.344(f) parameter 68. The 

exemption would apply to affected Frontier Airline aircraft of the specific configuration of 

A318/A319/A320 without the bogie gear. 

Frontier Airlines 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 a full configuration of AIC landing gears with 4 wheels on the main landing 

gear (wheels 1 ,2,3,4) and the availability of a so-called bogie landing gear with 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 of the normal brake 

pressure on individual wheels will be cycled each four seconds. The table below 

describes the scheme of sampling within this 4-second period. If a bogie landing gear is 

not configured, then the parameter pairs 5/7 and 618 will be recorded as NCO (noncomputed data), which results in a gap of 2 seconds within the 4-second frame. 

The petitioner requests relief from the following regulation: 

Section 121.344(f)( 1) requires that all turbine-engine-powered transport category 

airplanes manufactured after August 19, 2002, record the parameters listed in 

paragraphs (a)(1) through (a)(88) of that 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: 

Frontier Airline 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 after the date of the exemption granted in Ref I AI. 

Grant of exemption would be in the public interest: 

The FAA has determined from the information provided that good cause exists for 

granting this exemption. However, as the aircraft manufacturer and not a U.S. operator, 

Airbus cannot be granted an exemption from U.S. operating requirements. Exemption 

from an operating rule can be granted only to affected operators. Since the 345 affected 

airplanes represent a significant portion of the U.S. fleet, it is in the public interest for the 

FAA to allow the continued operation of the airplanes subject to certain conditions. 

Accordingly, the FAA will grant the relief requested by Airbus to the operators of these 

airplanes when requested. 

The action to be taken by the petitioner to provide a level of safety equivalent to 

that provided by the rule from which exemption is sought or the reason why a 

grant of exemption would not adversely affect public safety: 

There are mitigations in place to assist accident investigators. In the event of 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 data from 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 of the 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 of time. 

Use of the Exemption outside the United States: 

Frontier Airlines would like to utilize the privileges of this exemption outside the United 

States. The scheduled operations for this model aircraft include international operations 

primarily in Mexico and Central America. 
FRONTIER. 

A whole different animal: 

All MSN AJC Prod Engine Type 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-1 0 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)