AD 2001-12-14
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; Boeing Model 747-400 Series Airplanes |
| aircraft | The Boeing Company | 747-400D Series | Airworthiness Directives; Boeing Model 747-400 Series Airplanes |
| aircraft | The Boeing Company | 747-400F Series | Airworthiness Directives; Boeing Model 747-400 Series Airplanes |
Unsafe Condition
Miswiring of diodes in the heating system of the pitot static probes can lead to reduced power, causing ice accumulation on the probes, which may result in erroneous airspeed or altitude indications to the flight crew.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the pitot static probe heating system using a multimeter to verify continuity, absence of diodes, and diode orientation between relay sockets. If miswiring is detected, rewire the system prior to further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 15 months after the effective date of the AD.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 747-400 series airplanes, as listed in Boeing Alert Service Bulletin 747-30A2078, Revision 1, dated November 16, 2000, certificated in any category.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 series airplanes, that requires an inspection to detect miswiring of diodes in the heating system of the pitot static probes, and corrective action, if necessary. The actions specified by this AD are intended to prevent reduced power to the heating system of the pitot static probes, leading to ice accumulation on the pitot static probes, which could result in erroneous airspeed or altitude indications to the flight crew, and consequent reduced operational safety in all phases of flight. This action is intended to address the identified unsafe condition.
Document Text
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[Federal Register Volume 66, Number 119 (Wednesday, June 20, 2001)]
[Rules and Regulations]
[Pages 33016-33017]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-15209]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2000-NM-320-AD; Amendment 39-12269; AD 2001-12-14]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-400 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747-400 series airplanes, that
requires an inspection to detect miswiring of diodes in the heating
system of the pitot static probes, and corrective action, if necessary.
The actions specified by this AD are intended to prevent reduced power
to the heating system of the pitot static probes, leading to ice
accumulation on the pitot static probes, which could result in
erroneous airspeed or altitude indications to the flight crew, and
consequent reduced operational safety in all phases of flight. This
action is intended to address the identified unsafe condition.
DATES: Effective July 25, 2001.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 25, 2001.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,
Washington 98124-2207. This information may be examined at the Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Don Eiford, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2788; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION: A Notice of Proposed Rulemaking (NPRM) to
amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to
include an airworthiness directive (AD) applicable to certain Boeing
Model 747-400 series airplanes was published in the Federal Register on
February 21, 2001 (66 FR 10972). That action proposed to require an
inspection to detect miswiring of diodes in the heating system of the
pitot static probes, and corrective action, if necessary.
Editorial Change
The compliance time for rewiring of any miswiring, detected during
the special detailed inspection required by paragraph (a) of this AD,
was inadvertently omitted. Paragraph (a) of this AD has been changed to
require rewiring of any miswiring prior to further flight.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
The commenter supports the proposed rule.
Conclusion
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change described
previously. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
this AD.
Cost Impact
There are approximately 497 Model 747-400 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 69
airplanes of U.S. registry will be affected by this AD, that it will
take approximately 2 work hours per airplane to accomplish the required
actions, and that the average labor rate is $60 per work hour. Based on
these figures, the cost impact of the AD on U.S. operators is estimated
to be $8,280, or $120 per airplane.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the requirements of this AD
action, and that no operator would accomplish those actions in the
future if this AD were not adopted. The cost impact figures discussed
in AD rulemaking actions represent only the time necessary to perform
the specific actions actually required by the AD. These figures
typically do not include incidental costs, such as the time required to
gain access and close up, planning time, or time necessitated by other
administrative actions.
Regulatory Impact
The regulations adopted herein will not have a substantial direct
effect on the States, on the relationship between the national
Government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, it
is determined that this final rule does not have federalism
implications under Executive Order 13132.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3)
[[Page 33017]]
will not have a significant economic impact, positive or negative, on a
substantial number of small entities under the criteria of the
Regulatory Flexibility Act. A final evaluation has been prepared for
this action and it is contained in the Rules Docket. A copy of it may
be obtained from the Rules Docket at the location provided under the
caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (14 CFR part 39) as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
2001-12-14 Boeing: Amendment 39-12269. Docket 2000-NM-320-AD.
Applicability: Model 747-400 series airplanes, as listed in
Boeing Alert Service Bulletin 747-30A2078, Revision 1, dated
November 16, 2000; certificated in any category.
Note 1:
This AD applies to each airplane identified in the preceding
applicability provision, regardless of whether it has been modified,
altered, or repaired in the area subject to the requirements of this
AD. For airplanes that have been modified, altered, or repaired so
that the performance of the requirements of this AD is affected, the
owner/operator must request approval for an alternative method of
compliance in accordance with paragraph (b) of this AD. The request
should include an assessment of the effect of the modification,
alteration, or repair on the unsafe condition addressed by this AD;
and, if the unsafe condition has not been eliminated, the request
should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent reduced power to the heating system of the pitot
static probes, leading to ice accumulation on the pitot static
probes, which could result in erroneous airspeed or altitude
indications to the flight crew, and consequent reduced operational
safety in all phases of flight, accomplish the following:
Inspection
(a) Within 15 months after the effective date of this AD,
perform a special detailed inspection to detect miswiring of diodes
in the heating system of the pitot static probes by using a
multimeter to verify continuity between certain relay sockets,
absence of a diode between certain relay sockets, and diode
orientation between certain relay sockets, per Boeing Alert Service
Bulletin 747-30A2078, Revision 1, dated November 16, 2000. If any
miswiring is found, prior to further flight, rewire per Boeing 747-
400 Wiring Diagrams 30-31-11 and 30-31-21, as referenced in the
service bulletin.
Note 2:
Inspections accomplished prior to the effective date of this AD
per Boeing Alert Service Bulletin 747-30A2078, dated August 24,
2000, are considered acceptable for compliance with the applicable
action specified in this amendment.
Note 3:
For the purposes of this AD, a special detailed inspection is
defined as: ``An intensive examination of a specific item(s),
installation, or assembly to detect damage, failure, or
irregularity. The examination is likely to make extensive use of
specialized inspection techniques and/or equipment. Intricate
cleaning and substantial access or disassembly procedures may be
required.''
Alternative Methods of Compliance
(b) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA. Operators shall submit their requests through an
appropriate FAA Principal Maintenance Inspector, who may add
comments and then send it to the Manager, Seattle ACO.
Note 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
Special Flight Permits
(c) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Incorporation by Reference
(d) Except as provided by paragraph (a) of this AD, The actions
shall be done in accordance with Boeing Alert Service Bulletin 747-
30A2078, Revision 1, dated November 16, 2000. This incorporation by
reference was approved by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be
obtained from Boeing Commercial Airplane Group, P.O. Box 3707,
Seattle, Washington 98124-2207. Copies may be inspected at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
Effective Date
(e) This amendment becomes effective on July 25, 2001.
Issued in Renton, Washington, on June 11, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 01-15209 Filed 6-19-01; 8:45 am]
BILLING CODE 4910-13-P
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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