# AmericanAirlines®
MAINTENANCE &ENGINEERING CENTER February 24, 2011 U. S. Department of Transportation Docket Operations West Building Ground Floor, Room W12-140 1200 New Jersey Avenue, 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 months from December 6, 2010, to 14 CFR 121.344 to continue 14 CFR 121 operations oftwo additional 737-823 series aircraft. The expected deliveries of these aircraft are in May and June of 2011 , which will occur prior to Boeing's certification ofthe corrected Flight Data Recorder System data frame software

. This exemption request involves the same 737-7 data frame for which American was granted an exemption ofthe rudder pedal input force parameter and left elevator surface position parameter (Reference Exemption No

. 10173A. Regulatory Docket No. FAA-2010-1178 dated December 21, 2010)

. Applicable Sections: 14 CFR 121.344 

### (f) states " Forall turbine-engine-powered transport categoryairplanes that are manufacturedafterAugust 19, 2002 - (1) The parameters listedin paragraph (a) (1) through (88) ofthis section must be recorded within the rariges, accuracies, resolutions, andrecording intervals specifiedin Appendix M ofthis part. (2) In addition to the requirements ofparagraphs (f)(1) ofthis section, allBoeing 737 model airplanes must also comply with the requirements of paragraph (n) ofthis section." 14 CFR 121

.344 (n) states "In addition to allotherapplicable requirements ofthis section, all Boeing 737 model airplanes manufacturedafterAugust 18, 2000 must record the parameters listed in paragraphs (a)(88) through (a)(91) ofthis section within the ranges, accuracies, resolutions, andrecording intervals specified in Appendix 

### M to this part
. Compliance with this paragraph is required no laterthan February 2, 2011. " 14 CFR 121

.344 Appendix M (Note 18) states " Forallaircraftmanufactured on orafter December

### 6, 2010 , the seconds persampling interval is 

### O. 125

. Each input mustbe recorded at this rate. Alternatelysampling inputs (interleaving) to meet this sampling interval is prohibited

. " Extent of Relief This time-limited exemption would allow for the continued domestic and international operations ofthe following American Airlines operated B737-823 series aircraft (see Table 1) for 18 months after December 6, 2010, without the fully compliant recording interval ofthe rudder pedal force parameter and left elevator surface position paraf!1eter (see Table 2):

Make I Model Serial 

### # Line 

### # Registration 

### # Boeing / 737-823 40762 3634 N867NN Boeing 

### I 737-823 40763 3668 N868NN

MD

__ P.O

. BOX 582809, TULSA, OKLAHOMA 741 59-2809, CABLE ADDRESS AMAIRAmerican Airlines - 737NG Exemption Requesl


### Table 2 

### 121.344 (f) 

### Appendix M Parameter

### # Requirement Inputto DFDAU 

### 15 Pitch Control Left Elevator Position Data Surface Position (1 sample ofthe 8 Hz set every 5 seconds) 88 Rudder Pedal Input Force Rudder Pedal Force Data (1 sample ofthe 8 Hz set every 5 seconds)



### Reason for relief This exemption is necessitated by the Aircraft Manufacturer (Boeing) and the Digital Flight Data Acquisition Unit (DFDAU) system / software supplier's (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 American 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 later found that the left elevator position parameter and the rudder pedal force parameter were not being acquired completely, hence recorded properly. This FDRS configuration includes 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 of 2010 to meet the latest FAA regulations (§ 121.344 (f) Appendix M), which was effective starting December 6, 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 have time to complete the previous valid sample is used in the recording rather than 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 has verbally notified the FAA and is in the process offiling 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. Page 2 of4American Airlines - 737NG Exemption Request 

### Boeing has a pending contract in-work with and its acceptance the plan is certify the new DFDAU software in

...... ""'01\/ 

### 5 months. of certification is contingent on what is found during which may cause the schedule to move either left orthe right In any case, Boeing is working to certification of corrected software. Upon receipt ofthe Boeing Bulletin American Airlines will install this software within 90 days, terminating the exemption. Public Interest The granting ofthis exemption would be in the public by allowing American Airlines to continue providing service to domestic and international utilizing the B737-823 aircraft listed in Table 1. Failure to grant this exemption may require American Airlines to cancel flights and disrupt schedules causing significant financial loss as well as inconvenience and potential losttime cost to the traveling public. Affect on the Level of Safety American Airlines understands that the flight recorder an impact on the operation of aircraft, but they do provide a means based on availability after an accident or incident. American believes that infrequent loss ofthe rudder pedal parameter will not cause significant in a sufficient amount of data from this parameter. The availability of the rudder pedal position and rudder parameters will the missing data. for the Federal Register described in 14 11.87, American exemption not be published Registerand follow with request for comments to ensuing delay of ron'rlnn 

### the exemption. Airlines is requesting an exemption [from 14 CFR to allow for the operation of B737-823 series aircraft in domestic and international revenue service without of all 8 samples ofthe rudder left elevator position This exemption shall allow the Aircraft Manufacturer and the DFDAU System Provider (Teledyne) time to develop, validate, and to correct the anomaly and allow American Airlines time to install with minimal interruption to flight scheduling. Additional Information verbally notified the FAA and is in the offiling a Airworthiness Regulations" with the FAA stating that issue for continued operation.

30f4American Airlines - 737NG Exemption Request
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 for this model aircraft in American Airlines fleet includes international operations primarily in Mexico, Canada, Central America, South America and the Caribbean. Your consideration ofthe foregoing approval ofthis request is appreciated

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

.

# ;J~d)- William M. Cavitt Vice President Engineering, Performance and Quality Assurance On behalf of: American Airlines, Inc. Air Carrier Certificate AALA025A 3900 N Mingo Rd, MD 183 Tulsa, OK 74116 Phone: 918-292-2902 Fax: 918-292-1830 Email: bill.cavitt@aa

.com WMC/DZ: bt

cc: Federal Aviation Administration AAL Certificate Management Office c/o Mr. William T. Satterfield, PAl 14800 Trinity Blvd, St. 100 Fort Worth , Texas 76155 The Boeing Company B

. C. Groenewegen, Manager, Continued Airworthiness Twin Aisle Programs P

.O. Box 3707 Seattle WA 98214-2207

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