December 15, 2010 

U. S. Department of Transportation 

Docket Operations 

West Building Ground Floor, Room W12-140 

1200 New Jersey Avenue, SE. 

Washington DC. 20590 

Continental 

Airlines 

PMI 0111 ,'80x 4623 HQJOA 

Ho ',}fl TX 77210-4623 

COI'1!mefllal :om 

Subject Request for Exemption to Sections of 14 CFR Parts 121. and 121.344(f): 

Continental Airlines, Inc. would like to petition the Federal Aviation Administration for a 

time limited exemption of 18 months from December 6, 2010 to section 14 CFR part 121 , 

and 121 .344(f) to continue operation using a flight data recorder system that does not 

comply with those sampling requirements. 

Reference to the regulatory relief sought: 

Continental Airlines requests a time limited exemption to recording the flight data recorder 

parameter "All cockpit flight control input forces (control wheel, control column, rudder pedal).w for 

the rudder pedal input forces parameter as required by 14 CFR 121 .344 (f), to permit 

operation of some 737-824 and 737-924ER airplanes in FAR 121 service. 

14 CFR Part 121.344 (f) states U(fJ For all turbine-engine-powered transport category airplanes 

that are manufactured after August 19, 2002.(1) The parameters listed in paragraph (a) (1) through 

(88) of this section must be recorded within the ranges, accuracies, resolutions, and recording 

intervals specified in Appendix M of this part-. 

14 CFR Part 121 Appendix M (Note 18) states "For all aircraft manufactured on or after 

December 6, 2010, the seconds per sampling interval is 0.125. Each input must be recorded at this 

rate. Alternately sampling (nputs (interleaving) to meet this sampling interval is prohibited w

• 

Extent of Relief 

This exemption, specifically, would allow for the continued domestic and international 

operations of the following Continental Airlines operated 8737-824 and 8737 -924ER 

series aircraft (See Table 1) for 18 months from December 6, 2010 without a speCific 14 

CFR. Part 121 .344 (f). and 121 Appendix (M) mandated Digital Flight Data Acquisition 

Unit (DFDAU) recorded parameter (See Table 2): 

A STAR ALLIANCE MEMBER .,.: : 
Continental Airlines - 737NG Exempti()(l Request 

Table 1 (Aircraft Applicable to this Exemption) 

Make f Model Serial # Line # Registration # 

Boeing f 737-924 31655 3393 N38443 

Boeing f 737-924 31643 3417 N36444 

Boeing f 737-924 40000 3615 N73445 

Boeing f 737-824 31663 3464 N76528 

Boeing f 737-824 31652 3490 N76529 

Boeing f 737-824 39998 3521 N77530 

Boeing f 737-824 39999 3549 N77531 

Table 2 (System Signals recording 7 samples in lieu of 8 by the DFDAU) 

121 .344 (I) 

Parameter # 

88 

Reason for relief 

Appendix M 

Requirement Input to DFDAU 

All Cockpit flight control Rudder Pedal Input Forces 

Input forces (control wheel, 

control column, rudder pedal) 

This exemption is necessitated by the Aircraft Manufacturer (Boeing) and the Digital Flight 

Data Acquisition Unit (DFDAU) system I software supplier (Teledyne) need to develop, 

validate, and integrate the enhanced system software into the aircraft type design. This 

enhanced software will provide for the DFDAU recording of all regulatory required 

parameters and allow Continental Airlines time to install the software without significantly 

affecting flight operations. 

Background 

Summary: 

A 737NG Flight Data Recorder System (FORS) anomaly was discovered during additional 

Boeing testing of the system. The FDRS configuration included a Teledyne Digital Flight 

Data Acquisition Unit (DFDAU) with the 737-7 data frame enabled. The data frame is a 

512 words per second data frame that was certified in April 2010 to meet the latest FAA 

regulations (§ 121 .344 (f) Appendix M), which are effective Dec 6,2010. The following 

describes the anomaly and discusses Boeing's plan to correct the discrepancy. 

Discussion: 

After discovery of the Left Elevator Position parameter anomaly in October 2010, Boeing 

continued analysis of Flight Test data from a number of airplanes delivering with the 

Teledyne Controls DFDAU using the 737-7 data frame. Through that analysis, and 

confirmed by Teledyne, it was determined that the Rudder Pedal Force parameter exhibits 

the same anomaly discussed in exemption approval 10172 dated December 9,2010. 

Per FAA regulations (§ 121.344 (I) Appendix M (parameter group 88), as of Dec 6, 2010 

the FDRS must record control wheel, control column and rudder pedal input forces at 8 

samples per second. 

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Continental Airlines - 737NG Exemption Request 

FOR data analysis showed that at times, 1 of the 8 samples of rudder pedal force data, in 

a given second, could be stale (a previous sample). The anomalous rudder pedal forces 

data is usually present only once every 5 seconds (i.e. once every 5 seconds there are 

only 7 valid samples and one invalid sample in a one second acquisition period (Sub 

frame). It is possible to deduce a corrected rudder pedal force sample from linear 

interpolation between correct rudder pedal force samples around the anomaly. In 

summary, this anomaly can be addressed in ground processing of the data. 

The root cause of this anomaly is found in a DFOAU software acquisition timing error. 

Periodically, in a given parameter acquisition cycle, the DFDAU is requesting the 

acquisition of more parameter data than it has time to complete in that acquisition cycle. 

Because parameter acquisition does not have time to complete, the previous valid sample 

recorded one second earlier is used in the recording rather than the desired current 

sample. 

The DFOAU software is software loadable and Teledyne has informed Boeing that this 

anomaly can be fixed with a minor software revision resulting in new software part 

numbers. 

Plan to Correct Anomaly: 

Boeing has verbally notified the FAA and is in the process of filing a revised "Report of 

Noncompliance with Part 25 Airworthiness Regulations" with the FAA stating that the 

anomaly does not represent a safety issue for continued operation 

Boeing has a signed contract in-work with Teledyne and plans to certify the new DFOAU 

software in approximately 5-6 months. The date of certification is contingent on what is 

found during testing, which may cause the schedule to move either left or the right. In any 

case, Boeing is actively working to accelerate the certification of corrected software. 

Public Interest 

The granting of this exemption would be in the public interest by allowing Continental 

Airlines to continue providing service to domestic and international destinations utilizing 

the B737-824 and B737-924ER series aircraft listed in Table 1. 

Failure to grant this exemption would require Continental Airlines to cancel flights and 

disrupt schedules causing significant financial loss as well as impose inconvenience and 

potential lost-time cost to the traveling public. 

Affect on the Level of Safety 

The fact that the Digital Flight Data Recorder (OFOR) system is recording 7 samples per 

second in lieu of the 8 samples per second of the Rudder Pedal Force Parameter does 

not have an adverse affect on the normal or irregular operation of the aircraft. It is 

possible to deduce corrected Rudder Pedal Force using linear interpolation between 

correct rudder pedal force samples around the anomaly. In summary, this anomaly can 

be addressed in ground processing of the data. The manufacturer of the aircraft (Boeing) 

Page 3 of 5 
Continental Ail1ioes - 737NG Exemption Request 

has reviewed this exemption and has determined ''the issue is not considered to be a risk 

to current and future operation of the airpfane. " 

Summary for the Federal Register 

Continental Airlines requests relief from the requirement for publication of the summary in 

the Federal Register due to delaying the action on the petition would adversely affect 

operations and the traveling public. This petition for exemption has been filed as soon as 

the need for a petition was discovered. 

If a summary for the Federal Register is required for this request, Continental Airlines 

provides the following: 

Continental Airlines is requesting an exemption from 14 CFR Part 121.344(0 to allow for 

the continued operation of 8737-824 and B737-924ER series aircraft in domestic and 

international revenue service without the installed Digital Flight Data Acquisition Unit 

(DFDAU) recording all 8 samples of the rudder input forces data. This exemption shall 

allow the Aircraft Manufacturer (Boeing) and the DFDAU System Software Provider 

(Teledyne) time to develop, validate, and certify the software to correct the DFDAU 

anomaly and allow Continental Airlines time to install the software with minimal 

interruption to flight scheduling. 

Additional Information 

80eing has verbally notified the FAA and is in the process of filing a "Report of 

Noncompliance with Part 25 Airworthiness Regulations" with the FAA stating that the 

anomaly does not represent a safety issue for continued operation. 

Continental Airlines requests this petition for Exemption be expedited due to the 

requirements of 14 CFR Part 121 Appendix M (Note 18) are due December 6,2010. 

Use of the Exemption outside the United States 

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

States. The primary scheduled operations for this model aircraft in Continental Airlines 

fleet includes international operations primarily in Canada, Mexico, Central America and 

the Caribbean Islands. 

Your consideration of the foregoing and timely approval of this request is appreciated. If 

you have any questions regarding this request, please feel free to contact this office. 

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Contillental Airlines - 737NG Exemption ReQuest 

Rodney Luetzen 

Sr. Director 

Reliability and Quality Assurance 

On behalf of: Continental Airlines, Inc. 

Air Carrier Certificate CALA 014A 

1600 Smith Street 

Houston, Texas 77002 

Phone: 713-324-9244 

Fax: 7t3-324-169t 

Email: rodney.luetzen@coair.com 

cc: Federal Aviation Administration 

CALA Certificate Management Office 

2625 Bay Area Blvd. Suite 400 

Houston, Texas 77058 

The Boeing Company 

Brian Predmore - AC and Electrical Systems Group brian.k.predmore@boeing.com 

Ron Lockhart - OPERATIONAL SFTY & REGULATORY ronald.i.lockhart2@boeing.com 

Paul Sesny - OPERATIONAL SFTY & REGULATORY PauIASesny@boeing.com 

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