AD 89-21-09

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AD Number:
89-21-09
Document Type:
AD Final Rules
Docket Number:
89-NM-56-AD
Subject Heading:
Airworthiness Directives; BOEING Model 747 Series Airplanes
Subject:
Fuselage Skin Inspection
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
11/13/1989
Make:
The Boeing Company
Model:
747-100 Series | 747-100B Series | 747-100B SUD Series | 747-200B Series | 747-200C Series | 747-200...Show more
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Superseded AD: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Superseded By: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: 89-21-09
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   89-NM-56-AD

AMENDMENT:   39-6350

AD NUMBER:   89-21-09

SUBJECT HEADING:   Airworthiness Directives; BOEING Model 747 Series Airplanes

ACTION:  

SUMMARY:  

DATES:   Effective November 13, 1989.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
89-21-09 BOEING: Amendment 39-6350. Docket No. 89-NM-56-AD.
Applicability: Model 747 series airplanes, listed in Boeing Service Bulletin 747-53-2289, Revision 1, dated January 26, 1989, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent cabin pressure loss due to fatigue cracks in the skin at body station (BS) 460 just above left and right number 1 main entry doors, accomplish the following:

A. Prior to the accumulation of 10,000 landings, or within the next 1,000 landings after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 3,000 landings, conduct a high frequency eddy current (HFEC) inspection of the fuselage skin along the aft row of fasteners at the left and right BS 460 circumferential splices between stringers S-14E and S-16 for cracks, in accordance with Boeing Service Bulletin 747-53-2289, Revision 1, dated January 26, 1989. If the external doubler modification forward of BS 460 has not previously been installed in accordance with Boeing Service Bulletins 747-53-2181 or 747-53-2105, then also conduct a HFEC inspection of the fuselage skin along the forwardmost row of fasteners of the same skin splice.

B. To conduct the inspections required by this AD, remove the paint, using an approved chemical stripper, or ensure that the fastener heads are clearly visible.

C. If cracks are found when conducting the inspections required by paragraph A., above, accomplish either paragraph C.1. or C.2., below:

1. Prior to further flight, modify the affected BS 460 circumferential splice in accordance with Boeing Service Bulletin 747-53-2289, Revision 1, dated January 26, 1989. Cracks found in the internal splice strap while performing the modification must be repaired in accordance with the 747 Structural Repair Manual (SRM) concurrently with accomplishment of the skin modification.

2. Prior to further flight, perform an internal HFEC inspection of the aft row of fasteners of the internal splice strap to verify there are no cracks in the internal splice strap. This HFEC inspection must be conducted using a HFEC pencil probe, 360 degrees around the fastener heads, in accordance with Boeing Document D6-7170, Section 51-00-00, Figure 4. Repair the skin cracks prior to further flight, in accordance with the 747 SRM. Continue to inspect the unrepaired areas of the skin in accordance with paragraph A., above.

a. In addition, conduct an internal HFEC pencil probe inspection, 360 degrees around the fastener heads of the aft row of the internal splice strap at all fastener locations between stringer S-14E and S-15 between S-15 and S-16, at intervals not to exceed 1,000 landings, in accordance with the aforementioned Boeing Document. If cracks are found in the internal splice strap, prior to further flight, modify in accordance with paragraph C.1., above.

b. Prior to the accumulation of 20,000 landings, modify the affected BS 460 circumferential splice in accordance with paragraph C.1., above.

D. Terminating action for the HFEC inspection requirements of paragraph A., above, consists of modification of the left and right BS 460 circumferential splices between S-14E and S-16 in accordance with Boeing Service Bulletin 747-53-2289, original issue, dated October 22, 1987, or Revision 1, dated January 26, 1989.

E. For the purpose of complying with this AD, the number of landings may be determined to equal the number of pressurization cycles in which the cabin pressure differential was greater than 1.5 psi.

F. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add any comments and then send it to the Manager, Seattle Aircraft Certification Office.

G. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington.

This amendment (39-6350, AD 89-21-09) becomes effective on November 13, 1989.

FOOTER: