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## MUMITED

Federal Aviation Administration (FAA) Airpl1lDeDirectorate, ANM-114 1601 Lind Avenue, SW Renton, Washington 98055-4056 Subject: Docket No. 2002-NM-12-AD

Modification ofStatic Inverter

Dear Ladies IGentlemen: June 20, 2006

The referenced proposed rule advised ofand requested comments that will require modifying the static inverter byreplacing resistor Rl70 with anew resistor and relocating the new re!>istor.Wc concur with the contents ofthe proposed rule and offer the following comments. 1) The NPR.\.1supporting document Boeing Service Bulletin (SB) 757-24-0110 indicales torework the inverterS per Avionics Instruments Inc. (Am Service Bulletin 1.002-0102-1000.24-28. We suggest that the AD also approve the latest All SIB 1- 002-0102-1000-24-28 revision Aforreworking the inverters.,/ 2) Boeing Service Bulletin 757.24-0110 work instructions are divided into Group) and Group 2,based onthe Inverter partnumber as delIvered configuration. Group "1 Work Instructions indicate to inspect :he Ir:vener tegarding its part number and replace asnecessary. Group 2Work Instructions Indicate toreplace the Inverter. The current Boeing lPC 24-33.03.01 item 5. shows Inyerters part numbers: 707760-2 (S282TOO4-2),707760-3 (S282T004-3), and 707760.4 (S282TOO4-4) Post Alert SB 757-24A0069R I, are applicable toall 757 fleet, sdactually the referenced part numbers are spread out l.'Jroughthe fleet which diJagrees with thepurpose of SB 757. 24-0110 on separating the Work Instructions into aircraft Groups. We suggest disregarding the separation by Group and applying Group 1Work Instructions into all aircraft effectivity. 3) The NPRM comments "Request for Clarification ofTable I" indicate that Boeing Service Letter 757-SL-24-068-A (20 May 2003) suggests incorporation ofAll SB 1- 002-0102-1000-24.24 is supcrseded by the corresponding Boeing SB 757.24-0110 (Apri128. 2005) incorporating All SB 1_002.0102-1000-24.28. We were unable to verify this statement; both documents exist on the Boeing web site and do not show any cross-reference to each other inAffected Publications IReferences sections- In order to avoid confusion we suggest that the AD also approve AlI SB 1-002.0102- 1000-24-28 revision Afor tl:~rewo!;.:.4) The NPRM comments "Request for Clarification ofPart Number" indicate that part

number 1-001-0102-0265 is nOtan Inverter part number. We disagree with the NPRM statement. The Boeing 

### lPe for the B737-300f400f500 and B747-400 indicates thaI the Specification Number S282TOO4-5con'esponds toboth part numbers: 1.001- 0102-0265 and 1-002-0102.0265; both part numbers are also shown on B747-400 IPe 24-29-01-01 item IS. In order to avoid confusion we Sllggestthat the AD clarify the existence and applicability ofboth part numbers. 5) Avionics InstrUments Inc. SB 1_002_0102-1000-24-28 rev A (June 22,2005) "Instructions to modify part number ]_002-0102-0265 Boeing part number 5282TOO4-5" onpage 12of35 does not include part number 1-001-0102-0265. Also the An SB " KitNumber Table" on page 16of35 does nOIinclude part number 1- 001-0102-0265 (Boeing pin 5282TOO4-5). Also the All SB "Addendum 1Part/ Model Number Service Bulletin HistOry" onpage 30 of35 does not include part number 1-002-0102-0265 onBoeing part number 5282TOO4-5. Also the All SB "Functional Test Requirements, 1. General" onpage 31 of35 does not include part number 1-002-0102-0265 (Boeing $282TOO4-5). In order to avoid confusion we suggest the AD include both part numbers: 1-001-0102-0265 and 1-002-0102-0265, corresponding to Boeing part number 5282TOO4-5.

cc: John Brewster, United Airlines

- !NDEG Jeff Covington, United Airlines

- INDEG R. 1. Dial, United Airlines

- 5FOEG Felix Garcia, UniUodAirlines

- SFOEG Dave Hendryx, United Airlines

- SfOEG