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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 of Static Inverter

Dear Ladies I Gentlemen:

June 20, 2006

The referenced proposed rule advised of and requested comments that will require

modifying the static inverter by replacing resistor Rl70 with a new resistor and relocating

the new re!>istor. Wc concur with the contents of the proposed rule and offer the

following comments.

1) The NPR.\.1supporting document Boeing Service Bulletin (SB) 757-24-0110

indicales to rework 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 A for reworking the inverters.,/

2) Boeing Service Bulletin 757.24-0110 work instructions are divided into Group) and

Group 2, based on the Inverter part number as delIvered configuration. Group "1

Work Instructions indicate to inspect :he Ir:vener tegarding its part number and

replace as necessary. Group 2 Work Instructions Indicate to replace 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 to all 757 fleet, sd actually the referenced part

numbers are spread out l.'Jrough the fleet which diJagrees with the purpose of SB 757.

24-0110 on separating the Work Instructions into aircraft Groups. We suggest

disregarding the separation by Group and applying Group 1 Work Instructions into all

aircraft effectivity.

3) The NPRM comments "Request for Clarification of Table I" indicate that Boeing

Service Letter 757-SL-24-068-A (20 May 2003) suggests incorporation of All 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 in Affected Publications I References sections- In

order to avoid confusion we suggest that the AD also approve AlI SB 1-002.0102-

1000-24-28 revision A for tl:~ rewo!;.:.
4) The NPRM comments "Request for Clarification of Part Number" indicate that part

number 1-001-0102-0265 is nOt an Inverter part number. We disagree with the

NPRM statement. The Boeing lPe for the B737-300f400f500 and B747-400 indicates

thaI the Specification Number S282TOO4-5 con'esponds to both 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 Sllggest that the AD clarify

the existence and applicability of both 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" on page 12 of35 does not include part number 1-001-0102-0265. Also

the An SB " Kit Number Table" on page 16 of 35 does nOIinclude part number 1-

001-0102-0265 (Boeing pin 5282TOO4-5). Also the All SB "Addendum 1 Part/

Model Number Service Bulletin HistOry" on page 30 of 35 does not include part

number 1-002-0102-0265 on Boeing part number 5282TOO4-5. Also the All SB

"Functional Test Requirements, 1. General" on page 31 of 35 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