December 15, 2010 U. S. Department ofTransportation Docket Operations West Building Ground Floor, Room W12-140 1200 NewJerseyAvenue, SE. Washington DC, 20590 Subject: Request for Exemption to Sections of 14 CFR Part 121.344: American Airlines, Inc. would like to petition the Federal Aviation Administration for a timelimited exemption of 18 monthsfrom December6, 2010, to 14 CFR 121.344 to continue 14 CFR 121 operations ofthree 737-823 series aircraft using a flight data recorder system that does not fully comply with the recording interval requirements forthe rudder pedal inputforce parameter. This parameter is one ofthe three force parameters listed as parameter 88 in 14 CFR 121.344 (a). This exemption request involves the same 737-7 dataframe which American was granted an exemption ofthe left elevator position parameter (Reference Exemption No.10173, Regulatory Docket No. FAA-2010-1178 dated December 9,2010). The rudder pedal force anomaly behaves the same as the left elevator position parameter. Intermittently, from 4 to 5 seconds apart, 1 sample ofthe 8 samples per second records the previous second's sample. Applicable Sections: 14 CFR 121.344 (f) states 

### "Forallturbine-engine-powered transport categoryairplanes that are manufacturedafterAugust 19, 

### 2002 - (1) 

### The parameters listedin paragraph (a) (1) 

### through (88) ofthis section mustbe recorded within the ranges, accuracies, resolutions, andrecording intervals specifiedin Appendix

### M ofthis part. " 14 CFR 121.344Appendix M (Note 18) states 

### "Forallaircraftmanufacturedon orafter December

### 6, 2010, the secondspersampling intervalis 0.125. Each inputmustbe recordedat this rate. Altematelysampling inputs (interleaving) to meetthis sampling intervalis prohibited. "

Extent of Relief This time-limited exemption would allowforthe continued domestic and international operations ofthe following American Airlines operated B737-823 series aircraft (see Table 1) for 18 months after December6, 2010, without the fully compliant recording interval ofthe rudder pedal force parameter (see Table 2):

Make

### I Model Boeing 

### 1737-823 Boeing 

### 1737-823 Boeing 

### 1737-823

Page 1 of4 Serial

### # 31111 29554 40584 Line

### # 3487 3493 3499 Registration

### # N864NN N865NN N866NNAmerican Airlines - 737NG Exemption Request



### Table 2 121.344

### (f) Parameter

### # 88

Reason 

### for relief 

### Appendix 

### M Requirement Rudder Pedal Input Force 

### Inputto DFDAU Rudder Pedal Force Data (1 sample ofthe 8 Hz set eve 4 to 5 seconds

This exemption is necessitated by the Aircraft Manufacturer (Boeing) and the Digital Flight Data Acquisition Unit (DFDAU) system 

### I software supplier's (Teledyne) need to develop, validate, and integrate the enhanced system software into the aircrafttype design. This enhanced software will provide forthe DFDAU recording of all regulatory required parameters and allowAmerican Airlines time to install the software without significantly affecting flight operations. 

### Background Summary: A 737NG Flight Data Recorder System (FDRS) anomaly was discovered during Boeing flight line airplane operations. 

### It was found thatthe left elevator position parameterwas not being acquired, hence not recorded properly. Subsequent review ofthe data frame identified the rudder pedal force parameter as also having the same anomaly. American Airlines was not informed ofthe rudder pedal force parameter anomaly until December 13, 2010. Boeing has stated that their comprehensive review did not detectfurther anomalies. This FDRS configuration includes a Teledyne Digital Flight DataAcquisition Unit (DFDAU) with the 737-7 data frame enabled. The dataframe is a 512words per second dataframe thatwas certified in April of2010 to meetthe latest FAA regulations 

### (§ 121.344 (f) Appendix M), which was effective starting December6, 2010. The following describes the anomaly and discusses Boeing's plan to correct the discrepancy. Discussion: The root cause ofthis anomaly is found in a DFDAU 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 havetime to complete the previous valid sample is used in the recording ratherthan the desired current sample. The DFDAU software is on-wing 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 hasverbally notified the FAA and is in the process offiling a "Report of Noncompliance with Part 25Airworthiness Regulations" with the FAA stating that the anomaly does not represent a safety issue for continued operation. Page 2 of4American Airlines - 737NG Exemption Request 

### Boeing has a signed contract with Teledyne and plans to certifythe new DFDAU software in approximately 5-6 months. The date ofcertification is contingent on what is found during test which may cause the schedule to move either left or right. In any case, Boeing is actively working to accelerate the certification ofcorrected software. Upon receipt ofthe Boeing Service Bulletin and certified software, American Airlines will install this software within 90 days, terminating the need forthe exemption.

Public Interest The granting ofthis exemption would be in the public interest by allowing American Airlines to continue providing service to domestic and international destinations utilizing the B737-823 series aircraft listed in Table 1. Failure to grantthis exemption may require American Airlines to cancel flights and disrupt schedules causing significant financial loss as well as impose inconvenience and potential losttime cost to the traveling public.

Affect on the Level ofSafety American Airlines understands that the flight recorder parameters do not have an impact on the safe operation of aircraft, but they do provide a means for increasing safety based on availability ofdata after an occurrence, accident or incident. American believes that the infrequent loss of one sample ofthe 8-Hz sampling ofthe rudder pedal force parameterwill not cause significant burden in obtaining a sufficient amount ofdata from this parameter. The availability ofthe rudder pedal position and rudder parameters will also enhance the missing data. Summaryforthe Federal Register As described in 14 CFR 11.87, American Airlines requests that this exemption not be published in the Federal Register and follow with request for comments due to the ensuing delay of potentially granting the exemption. American Airlines is requesting an exemption from 14 CFR Part 121.344to allow forthe continued operation of B737-823 series aircraft in domestic and international revenue service withoutthe recording ofall 8 samples ofthe rudder pedal force 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 allowAmerican Airlines time to install the software with minimal interruption to flight scheduling.

Use ofthe Exemption outside the United States American Airlines would like to utilize the privileges ofthis exemption outside the United States. The primary scheduled operations forthis model aircraft in American Airlines fleet includes international operations primarily in Mexico, Canada, Central America, South America and the Caribbean.

Page 3 of4American Airlines - 737NG Exemption Request 

### Your consideration ofthe foregoing and expedited approval ofthis request is appreciated. Ifyou have any questions regarding this request, please feel free to contactthis office. Sincerely,

# ~t?i?~ Vice President Engineering, Performance and QualityAssurance On behalf of: American Airlines, Inc. Air Carrier CertificateAALA025A 3900 N Mingo Rd, MD 183 Tulsa, OK 74116 Phone: 918-292-2902 Fax: 918-292-1830 Email: bill.cavitt@aa.com

cc: Federal Aviation Administration AAL Certificate Management Office c/o Mr. William 

### T. Satterfield, PAl 14800 Trinity Blvd, SI. 100 FortWorth, Texas 76155 The Boeing Company B. C. Groenewegen, Manager, Continued Airworthiness Twin Aisle Programs P.O. Box 3707 SeattleWA 98214-2207

Page 4014