Source: https://www.federalregister.gov/documents/2004/11/24/04-26027/airworthiness-directives-boeing-model-747-400f-series-airplanes
Timestamp: 2018-03-24 16:50:03
Document Index: 675450797

Matched Legal Cases: ['art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 3']

A Proposed Rule by the Federal Aviation Administration on 11/24/2004
We must receive comments on this proposed AD by January 10, 2005.
69 FR 68277
68277-68280 (4 pages)
Docket No. FAA-2004-19678
Directorate Identifier 2004-NM-62-AD
04-26027
Differences Between the Alert Service Bulletin and This Proposed AD
Inspections/Repair/Modification
https://www.federalregister.gov/d/04-26027 https://www.federalregister.gov/d/04-26027
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-400F series airplanes. This proposed AD would require initial detailed and open-hole high frequency eddy current inspections for cracking of the web, upper chord, and upper chord strap of the upper deck floor beams, and repair of any cracking. This proposed AD also would require a preventive modification of the upper deck floor beams, and repetitive inspections for cracking after accomplishing the modification. This proposed AD is prompted by reports of fatigue cracking found on the upper deck floor beam to frame attachment points. We are proposing this AD to prevent fatigue cracks in the upper chord, upper chord strap, and the web of the upper deck floor beams and resultant failure of the floor beams. Failure of a floor beam could result in damage to critical flight control cables and wire bundles that pass through the floor beam, and consequent loss of controllability of the airplane. Failure of the floor beam also could result in the failure of the adjacent fuselage frames and skin, and consequent rapid decompression of the airplane.
DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically. Start Printed Page 68278
Technical information: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437; fax (425) 917-6590.
We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19678; Directorate Identifier 2004-NM-62-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.
On January 29, 2004, we issued AD 2004-03-11, amendment 39-13455 (69 FR 5920, February 9, 2004). That AD applies to certain Boeing Model 747-200C and -200F series airplanes, and requires repetitive inspections to find fatigue cracking in the upper chord of the upper deck floor beams, and repair if necessary. For certain airplanes, that AD also provides an optional repair/modification, which defers certain repetitive inspections.
Since issuance of AD 2004-03-11, we have received reports indicating that additional fatigue cracking was found on the upper deck floor beam to frame attachment points, on certain Model 747-200F series airplanes. The upper deck floor beams on certain 747-400F series airplanes are similar to those on the affected 747-200F series airplanes. In light of these reports, we have determined that it is necessary to issue the proposed AD at this time to ensure the continued operating safety of the affected airplane fleet. Therefore, all of these models may be subject to the same unsafe condition. Failure of a floor beam due to fatigue cracking could result in damage to critical flight control cables and wire bundles that pass through the floor beam, and consequent loss of controllability of the airplane. Failure of the floor beam also could result in the failure of the adjacent fuselage frames and skin, and consequent rapid decompression of the airplane.
We have reviewed Boeing Alert Service Bulletin 747-53A2443, dated May 9, 2002. The service bulletin describes procedures for a detailed inspection for cracking of the web, upper chord and upper chord strap of body stations 340 through 520 inclusive, of the upper deck floor beams; an open-hole high frequency eddy current (HFEC) inspection for cracking of the fastener holes of the web, upper chord, and upper chord strap; and repair of any cracking. If any cracking is found, the procedures in the service bulletin include repairing the cracking and accomplishing a preventive modification before further flight, or contacting the manufacturer for repair instructions if the cracking exceeds certain limits.
If no cracking is found, the procedures in the service bulletin include two options: Modifying the upper chord of the upper deck floor beams before further flight, or repeating the detailed and open-hole inspections before the accumulation of 20,000 total flight cycles, then accomplishing the preventive modification before further flight. Accomplishing the preventive modification extends the compliance time for the next detailed and open-hole or surface HFEC inspections of the upper deck floor beams to 15,000 flight cycles after accomplishing the modification.
For the post-modification inspection, the service bulletin gives the option of either repeating the detailed and surface HFEC inspections every 1,000 flight cycles, or repeating the detailed and open-hole HFEC inspections every 5,000 flight cycles.
Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. Start Printed Page 68279
We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require initial detailed and open-hole HFEC inspections for cracking of the web, upper chord, and upper chord strap of the upper deck floor beams, and repair of any cracking. The proposed AD also would require a preventive modification of the upper deck floor beams, and repetitive inspections for cracking after accomplishing the modification. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Differences Between the Alert Service Bulletin and This Proposed AD.”
The service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, but this proposed AD would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA, or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings.
The service bulletin refers to a “detailed visual inspection” for cracking of the web, upper chord, and strap of the upper deck floor beams. We have determined that the procedures in the service bulletin should be described as a “detailed inspection.” Note 1 has been included in this proposed AD to define this type of inspection.
Although the service bulletin does not list a grace period in the compliance times for the initial inspections and the preventive modification, this proposal adds a grace period to those compliance times. We find that such a grace period will keep airplanes from being grounded unnecessarily.
This proposed AD would affect about 53 airplanes worldwide and 13 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD, depending on the airplane configuration:
Pre-modification/inspections 11 $65 $0 $715 13 $9,295.
Modification/Inspections done during modification 498 or 524 65 13,554 or 14,874 45,924 or 48,934 13 597,012 or 636,142.
Post-modification inspections 66 65 0 4,290, per inspection cycle 13 55,770.
Boeing: Docket No. FAA-2004-19678; Directorate Identifier 2004-NM-62-AD.
(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by January 10, 2005.
(c) This AD applies to Model 747-400F series airplanes, certificated in any category; as listed in Boeing Alert Service Bulletin 747-53A2443, dated May 9, 2002.
(d) This AD was prompted by reports of fatigue cracking found on the upper deck floor beam to frame attachment points. We are issuing this AD to prevent fatigue cracks in the upper chord, upper chord strap, and web of the upper deck floor beams and the resultant failure of the floor beams. Failure of a floor beam could result in damage to critical flight control cables and wire bundles that pass through the floor beam, and consequent loss of controllability of the airplane. Failure of the floor beam also could result in the failure of the adjacent fuselage frames and skin, and consequent rapid decompression of the airplane.
(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Start Printed Page 68280
(f) For the purposes of this AD, the term “service bulletin” means the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2443, dated May 9, 2002.
(g) Before the accumulation of 15,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later: Accomplish detailed and open-hole high frequency eddy current (HFEC) inspections for cracking of the web, upper chord, and upper chord strap of the upper deck floor beams, by doing all the applicable actions in accordance with Part 3.B.1. of the service bulletin.
(h) If any crack is found during any inspection required by paragraph (g) of this AD: Before further flight, accomplish the actions required by paragraph (h)(1) and (h)(2) of this AD.
(1) Repair in accordance with the service bulletin; except where the service bulletin specifies to contact Boeing for appropriate action, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
(2) Accomplish the inspections and preventive modification of the floor beams by doing all the actions in accordance with Part 3.B.2. or Part 3.B.3. of the service bulletin, as applicable. If any crack is found during any inspection, before further flight, repair as required by paragraph (h)(1) of this AD.
(i) If no crack is found during any inspection required by paragraph (g) of this AD: Accomplish the actions required by either paragraph (i)(1) or (i)(2) of this AD, at the time specified.
(1) Before further flight: Accomplish the inspections and preventive modification of the floor beam by doing all the actions in accordance with Part 3.B.2 or Part 3.B.3. of the service bulletin, as applicable. If the preventive modification is performed concurrently with the inspections required by paragraph (g) of this AD, the upper chord straps must be removed when performing the open-hole HFEC inspection. If any crack is found during any inspection, before further flight, repair as required by paragraph (h)(1) of this AD.
(2) Before the accumulation of 20,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever is later: Accomplish the inspections and preventive modification of the upper deck floor beams, by doing all the actions in accordance with Part 3.B.2. or 3.B.3. of the service bulletin, as applicable. If any crack is found during any inspection, before further flight, repair as required by paragraph (h)(1) of this AD.
(j) Within 15,000 flight cycles after accomplishing the applicable preventive modification required by paragraph (h)(2), (i)(1), or (i)(2) of this AD: Accomplish the inspections required by either paragraph (j)(1) or (j)(2) of this AD; if any crack is found during any inspection, before further flight, repair as required by paragraph (h)(1) of this AD.
(1) Accomplish detailed and surface HFEC inspections for cracking of the web, upper chord, and upper chord strap of the upper deck floor beams, by doing all the applicable actions in accordance with Part 3.B.4. of the service bulletin. If no crack is found, repeat the inspections at intervals not to exceed 1,000 flight cycles.
(2) Accomplish detailed and open-hole HFEC inspections for cracking of the web, upper chord, and strap of the upper deck floor beams, by doing all the applicable actions in accordance with Part 3.B.5. of the service bulletin. If no crack is found, repeat the inspections at intervals not to exceed 5,000 flight cycles.
There is no terminating action currently available for the repetitive inspections required by this AD.
[FR Doc. 04-26027 Filed 11-23-04; 8:45 am]