AD 75-08-11

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AD Number:
75-08-11
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; ROCKWELL INTERNATIONAL Models NA-265, T-39A, NA-265-20, T-39B, NA-265-30, ...Show more
Subject:
Electrical Power in Flight
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
08/05/1976
Make:
Sabreliner Corporation
Model:
NA-265 | NA-265-20 | NA-265-30 | NA-265-40 | NA-265-60 | NA-265-70
Product Type:
Aircraft
Product Subtype:
Large Airplane
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 75-08-11
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-2681

AD NUMBER:   75-08-11

SUBJECT HEADING:   Airworthiness Directives; ROCKWELL INTERNATIONAL Models NA-265, T-39A, NA-265-20, T-39B, NA-265-30,
T-39D, NA- 265-40, NA-265-60 and NA-265-70 Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective August 5, 1976.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   75-08-11 ROCKWELL INTERNATIONAL: Amendment 39-2161 as amended by Amendment 39-2681. Applies to NA-265, T-39A, NA-265-20, T-39B, NA-265-30, T-39D, NA- 265-40, NA-265-60 and NA-265-70 Airplanes, certificated in all categories.

For paragraphs (a) through (f), compliance required within the next 50 hours time in service or 30 days, whichever is sooner, after April 14, 1975 (the effective date of Amendment 39-2161, AD 75-08-11), unless already accomplished.

For paragraphs (g) through (i), compliance is required as indicated.

To prevent loss of electrical power in flight, accomplish the following:

(a) Perform an inspection of the electrical cable system at fuselage stations #143 and #333 as follows:

(1) Examine cable lugs for looseness on cable or Essential Bus circuit breakers; if readily movable by hand applied force, replace that particular circuit breaker, and cable terminal, if applicable.

(2) Examine circuit breakers for cracked cases. Application of excess torque on lug attaching bolt may cause cracks emanating from area adjacent to breaker terminal. Replace units having such cracks.

(3) Determine by inspection that the cable lug is attached to the circuit breaker by not less than 50 inch-pounds torque; if below 50 inch-pounds, adjust to 50-60 inch- pounds.

(b) For airplane Model NA-265-40 Serial Numbers 282-98 through 282-137 and Model NA-265-60 Serial Numbers 306-64 through 306-93:

(1) Test the circuit breakers and replace, if necessary, as specified in Sabreliner Service Bulletin 74-28, as issued on September 20, 1974, or as revised January 15, 1975, or later FAA-approved revisions; or

(2) Replace the 10 Essential Bus circuit breakers with Rockwell International supplied replacements which have been tested. (These are date stamped with black ink by Rockwell International, and must be dated either prior to January 1, 1970, or after July 7, 1974. During the interval between these dates, tests were conducted only on selected samples, and such units must not be used, unless tested as specified in Service Bulletin 74-28.)

(c) Revise AFM Limitations Section as follows:

ESSENTIAL BUS CIRCUIT BREAKERS. All 28V DC, 100 AMP Essential Bus circuit breakers (cockpit and cabin) must be checked and engaged (pushed in) during the pre-flight (prior to first flight of the day) inspection.

(d) Install a placard in full view of the crew:

"PRIOR TO FIRST FLIGHT OF DAY - DETERMINE THAT COCKPIT AND CABIN ESSENTIAL BUS CIRCUIT BREAKERS ARE PUSHED IN."

(e) Install a placard on or immediately adjacent to the aft cabin circuit breaker panel:

"CIRCUIT BREAKERS ON THIS PANEL ARE ESSENTIAL TO SAFETY AND MUST BE READILY ACCESSIBLE TO THE CREW IN FLIGHT - DO NOT OBSTRUCT."

(f) Examine circuit breakers in spares stock. Either remove those date stamped by Rockwell International during interval of January 1, 1970, through July 7, 1974, and identify in a manner to preclude installation in NA-265 series airplanes, or perform the one hour functional test specified in Service Bulletin 74-28 prior to returning to spares.

(g) After August 5, 1976 (the effective date of Amendment 39-2681) the placard specified in paragraph (e), above, may be removed when:

(1) A placard is installed on or immediately adjacent to the circuit breaker access cover:

'CIRCUIT BREAKER ACCESS',
and
(2) A placard is installed on or immediately adjacent to the circuit breaker panel so that it is visible when the circuit breaker access cover is opened:

'CIRCUIT BREAKERS ON THIS PANEL ARE ESSENTIAL TO SAFETY AND MUST BE ACCESSIBLE FOR INSPECTION ON THE GROUND AND IN FLIGHT'

(h) Before September 1, 1976, unless already accomplished, revise the FAA- approved Airplane Flight Manual (AFM) appropriate to the airplane model as listed below, by incorporating the AFM revision as dated, or later FAA-approved revision. (This revised manual material incorporates revised Certificate Limitations pertaining to the circuit breaker preflight check, and new Emergency Procedures covering the failure of the 28V DC Essential Bus system.)

Model	AFM	Date of AFM Revision
NA-265(T-39A)	NA-61-3	July 19, 1976
NA-265-20 (T-39B)	NA-61-3	July 19, 1976
NA-265-30 (T-39D)	NA-61-3	July 19, 1976
NA-265-40 (S/N 1-97)	NA-62-1300	July 19, 1976
(S/N 98-137)	NA-72-25	July 19, 1976
NA-265-60	NA-66-1030	July 19, 1976
NA-265-70	NA-69-422	July 19, 1976

Concurrently with incorporating this AFM revision, remove AFM material specified in paragraph (c) and the placard specified in paragraph (d).

(i) For models NA-265-40, NA-265-60 and NA-265-70

(1) Before October 15, 1976, unless already accomplished, comply with Part I of Rockwell International Service Bulletin No. 11 as revised May 14, 1976 or later FAA- approved revision, to provide improved circuit breaker cooling at Station 333.

(2) Before April 25, 1977, unless already accomplished:

(i) Comply with Part II (replacement of five 100 ampere circuit breakers with five 140 ampere circuit breakers at Station 333 and providing additional circuit breaker cooling), of Rockwell International Service Bulletin No. 11 as revised May 14, 1976, or later FAA-approved revision, and

(ii) Install an 'Essential Bus Circuit Breaker Out' caution light and test circuit system in accordance with Rockwell International Service Bulletin No. 75-20 as revised May 24, 1976 or later FAA-approved revision.

(iii) When the replacement of the five circuit breakers in accordance with subparagraph (i)(2)(i) is accomplished the requirements of Paragraph (b) no longer apply to the five circuit breakers located at station 333.

Equivalent procedures may be approved by the Chief, Aircraft Engineering Division, FAA Western Region, upon submission of adequate substantiation data.

Aircraft may be flown to a base for performance of work required by this AD per FAR's 21.197 and 21.199.

Amendment 39-2161 became effective April 14, 1975.

This amendment 39-2681 becomes effective August 5, 1976.

FOOTER: