[4910-13-

DEPARTMENT OF TRANSPORT AnON

Federal Aviation Administratibn

14 CFR Part 39

DI

(Docket No. FAA-20lOJh+; birectoratc Identifier 2009-NM-263-AD]

RlN 2120-AA64

Airworthiness Directives; The Cessna Aircraft Company Model 750 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTiON: Notice of proposed mlemaking (NPRM).

SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain M

750 airplanes. This proposed AD would require an inspection to determine the serial - (O~

numbers of the auxiliary power unit (APU) generator and the left and right engine D ' :t~~·

generators, and related corrective actions if necessary. This proposed AD would also

require revising the airplane flight manual. This proposed AD results from a report 0

DC generator overvoltage event which caused smoke in the cockpit and damage to

numerous avionics and electrical components. We are proposing this AD to detect an

correct an overvoltage condition all the DC electrical busses caused by exciter stator

winding failures, and subsequent failure of the generator control unit (GCU) overvolt

protection circuitry, which could result in damage to critical electrical and avionics

components.

DATES: We must receive comments on this proposed AD by [INSERT DATE 45

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES: You may send c.omments by any of the following methods:

• Fed.eral eRulemaking Portal: Go to http://v.'ww.regulations.gov.Followthe

instructions for submitting comments .

• Fax: 202-493-225l.

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FAA Form 1360-14_1 (6-89) 0FFtCtAl FilE COPY

* u.s. GOVERNMENT PRINTING OFFICE: 'rs-769·211
{4910-13-P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Pa,'39

IDocket No. FAA-2010M++++; Directorate Identifier 2009-NM-263-ADj

RIN 212Q..AA64

Airworthiness Directives; The Cessna Aircraft Company Model 750 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACfJON: Notice of proposed rulemaking (NPRM).

SUMMARY; We propose to adopt a new airworthiness direclivc (AD) for certain Mo

750 airplanes. This proposed AD would require an inspection to dctcm1inc the serial

numbers of the auxiliary power unit (APU) generator and the left and right engine DC

generators, and related corrective actions if necessary. This prdposed AD would also

require revising the airplane Hight manual. This proposed AD results from a report of

DC generator overvoltage event which caused smoke in the cockpit and damage 10

numerous avionics and electrical components. We are proposing this AD to detect and

correct an overvoltage condition on thc DC electrical busses caused by exciter stator

winding failures. und subsequent failure ofthc generator control unit (GCU) ovcrvolta

protection circuilry, which could result in damage to critical electrical and avionics

components.

DATES: We must receive comments on this proposed AD by [INSERT DATE 45

DAYS AFrER DATE OF PUBLICA nON IN THE FEDERAL REGISTER).

ADDRESSES: You may send comments by any oflhe following methods:

• Federal cRulcmaking Portal: Go to hllr:!:www.r~glllalillns.gllY. Follow the

instructions for submit1ing comments .

• Fax: 202-493-2251.

-..••" .,' ~~

FAA Form 1360-14.1 (6-89) OFFICIAL FILE COPY