[Federal Register Volume 59, Number 43 (Friday, March 4, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-4952]
[[Page Unknown]]
[Federal Register: March 4, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 92-NM-48-AD; Amendment 39-8593; AD 93-11-01]
Airworthiness Directives; McDonnell Douglas Model DC-9-10 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; correction.
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SUMMARY: This document corrects information in an existing
airworthiness directive (AD) that is applicable to certain McDonnell
Douglas Model DC-9-10 series airplanes. Among other things, the
existing AD currently requires a modification of the wing leading edge
bleed air anti-ice system so that it can operate on the ground to
prevent ice reformation after deicing procedures have been
accomplished, and a related revision to the Airplane Flight Manual
(AFM). The actions specified in that AD are intended to prevent
degradation of lift due to ice accumulation on the wing leading edge.
This amendment corrects the instructional language in the required AFM
revision related to operation of the system on the ground. This action
is prompted by apparent confusion that this language has created among
affected operators in attempting to comply with the rule.
DATES: Effective July 22, 1993. The incorporation by reference of
certain publications listed in the regulations was previously approved
by the Director of the Federal Register as of July 22, 1993 (58 FR
33898, June 22, 1993).
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
California 90801-1771, Attention: Business Unit Manager, Technical
Administrative Support, Dept. L51, Mail Code 2-98. 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 FAA, Los Angeles Aircraft Certification Office,
3229 East Spring Street, Long Beach, California; or at the Office of
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3229 East
Spring Street, Long Beach, California 90806-2425; telephone (310) 988-
5336; fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: On May 26, 1993, the FAA issued AD 93-11-01,
Amendment 39-8593 (58 FR 33898, June 22, 1993), that is applicable to
certain McDonnell Douglas Model DC-9-10 series airplanes. That AD
superseded an existing AD that had required a revision to the FAA-
approved Airplane Flight Manual (AFM) to specify that takeoff must not
be initiated unless the flight crew verifies that a visual and physical
check of the leading edge and upper wing surfaces have been
accomplished and that the wing is clear of all ice, frost, and snow
accumulation. AD 93-11-01 added a requirement to modify the wing
leading edge bleed air anti-ice system so that it can operate on the
ground to prevent ice from reforming after deicing procedures have been
accomplished. The actions specified in that AD are intended to prevent
degradation of lift due to ice accumulation on the wing leading edge.
Recently, the FAA has become aware of the fact that certain
language contained in the required AFM limitation, relative to
operation of the wing leading edge bleed air anti-ice system, has
created confusion among affected operators when attempting to comply
with the rule.
Specifically, paragraph (d)(2) of AD 93-11-01 requires that the
Limitations Section of the AFM be revised to require that ``the bleed
air anti-ice system must be on whenever conditions exist or are
anticipated, including on-ground operation.'' This phrase apparently
has been interpreted to mean that operators must have the system on
during the brief period during takeoff from aircraft rotation to about
100 feet above ground level where the extraction of engine bleed air
for the anti-ice system penalizes second-segment climb performance.
Such a performance penalty could be as much as 4,000 pounds, which is
roughly equivalent to off-loading 20 passengers. One operator contends
that a penalty of this magnitude cannot be absorbed by operators and
makes operation of Model DC-9-10/-15 aircraft ``economically not
viable.''
The purpose of the required AFM limitation was meant to ensure that
the anti-ice system modification is used to provide the on-ground
protection for which it is intended; the manner in which the system is
normally operated during flight was not meant to be changed. The FAA
acknowledges that the language of the AFM limitation as it appears
currently in the AD could be interpreted to apply to both the ground
and flight phases of airplane operation. Since this clearly was not the
FAA's intent, the FAA has determined that it is appropriate to take
action to correct the wording of the AFM limitation in AD 93-11-01 to
specify that the bleed air anti-ice system must be on whenever icing
conditions exist or are apparent, when on the ground, until immediately
prior to commencement of takeoff roll.
This corrected wording will clearly indicate that the limitation
applies only to operation of the system while the airplane is on the
ground until prior to takeoff. The selection of the anti-ice system
during takeoff has always been the pilot's decision, and the FAA
intends that it continue to be so.
Additionally, another item that appeared in the preamble to AD 93-
11-01 has apparently created some confusion. In that preamble, the FAA
stated the following in its description of the unsafe condition:
``The FAA notes that the description of the addressed unsafe
condition, as discussed in the proposal, implied that the condition
is a result of icing effects on both the wing upper surface and the
wing leading edge. That language was inaccurate; the unsafe
condition is likely to occur as the result of icing effects on the
wing leading edge, not the wing upper surface.''
The FAA has reconsidered this statement and finds that, while the
modification of the wing leading edge bleed air anti-ice system
required by AD 93-11-01 is effective only on ice forming on the wing
leading edge, it would be misleading to state the unsafe condition
addressed by that AD results only from that phenomenon. The unsafe
condition addressed is that which is caused by ice contamination on the
wing leading edge and upper surface; this condition can result in the
degradation of wing lift, and can result in the airplane stalling at
lower than normal angles-of-attack during takeoff. Therefore, the FAA
hereby clarifies this point by replacing the previously used language
with the following:
``The modification to the wing leading edge bleed air de-icing
system, which is required by this AD, prevents ice/frost/snow from
reforming on the wing leading edge only, after the airplane has been
deiced. The wing leading edge area is the most critical from a loss
of lift standpoint. However, because contamination on the upper
surface of the wing can also impact lift and stall speeds, assurance
that ice/frost/snow is not present on the wing leading edge and
upper surface requires operation in accordance with the
comprehensive requirements of Section 121.629(c) (Amendment 121-231)
of the Federal Aviation Regulations (FAR), or the accomplishment of
visual and physical (hands-on) inspections of both the leading edge
and the wing upper surface as required by this AD.''
Additionally, the address for obtaining copies of the referenced
service material from the McDonnell Douglas Corporation has been
corrected.
Action is taken herein to correct these errors and to correctly add
the AD as an amendment to Sec. 39.13 of the FAR (14 CFR part 39). The
effective date of the rule remains July 22, 1993.
The final rule is being reprinted in its entirety for the
convenience of affected operators.
Since this action only corrects wording in an existing rule, it has
no adverse economic impact and imposes no additional burden on any
person. Therefore, notice and public procedures hereon are unnecessary.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety. Adoption of the Correction.
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations as follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by correctly adding the following
airworthiness directive (AD):
93-11-01 McDonnell Douglas: Amendment 39-8593. Docket 92-NM-48-AD.
Supersedes AD 92-03-01, Amendment 39-8155.
Applicability: Model DC-9-11, -12, -13, -14, -15, and -15F
series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent degradation of lift due to ice accumulation on the
wing leading edge, accomplish the following:
(a) Except as provided by paragraph (b) of this AD, within 10
days after January 17, 1992 (the effective date of AD 92-03-01,
Amendment 39-8155), revise the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) to include the following. This
may be accomplished by inserting a copy of this AD in the AFM.
``Wing De-icing Prior to Takeoff
Caution
The Model DC-9-10 series airplane has a wing design with no
leading edge high lift devices, such as slats. Wings without leading
edge devices are particularly susceptible to loss of lift due to
wing icing. Minute amounts of ice or other contamination (equivalent
to medium grit sandpaper) on the leading edges or wing upper
surfaces can cause a significant reduction in the stall angle-of-
attack. This can increase the stall speed up to 30 knots. The
increased stall speed can be well above the stall warning (stick
shaker) activation speed.
[End of Cautionary Note]
The leading edge and upper wing surfaces must be physically
checked for ice/frost when the airplane has been exposed to
conditions conducive to ice/frost formation. Takeoff may not be
initiated unless the flight crew verifies that a visual check and a
physical (hands-on) check of the leading edge and upper wing
surfaces have been accomplished, and that the wing is clear of ice/
frost/snow accumulation. Icing/frost/snow conditions exist when the
Outside Air Temperature (OAT) is below 6 degrees C (42 degrees F);
and either the difference between the dew point temperature and OAT
is less than 3 degrees C (5 degrees F), or visible moisture (rain,
drizzle, sleet, snow, fog, etc.) is present.
Note
This limitation does not relieve the requirement that aircraft
surfaces are free of ice, frost, and snow accumulation as required
by Federal Aviation Regulations Sections 91.527 and 121.629.
[End of Note]''
(b) Paragraph (a) of this AD does not apply to any airplane that
is both operated in accordance with Federal Aviation Regulation
(FAR) 121.629(c), Amendment 121-231, and modified in accordance with
either paragraph (c)(1) or (c)(2) of this AD.
(c) Within 9 months after the effective date of this amendment,
accomplish the procedures specified in either paragraph (c)(1) or
(c)(2) of this AD:
(1) Modify the bleed air anti-ice system so that it can operate
on the ground to prevent ice reformation on the wing leading edges
after ground equipment has been utilized to properly deice the
airplane, and to minimize the effect of undetected ice/frost/snow
contamination. Accomplish the modification in accordance with a
method approved by the Manager, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Or
(2) Install a supplemental on-ground wing leading edge ice
protection system in accordance with McDonnell Douglas DC-9 Service
Bulletin 30-65, dated October 8, 1992.
(d) Upon the accomplishment of the modification required by
paragraph (c) of this AD, revise the AFM in accordance with either
paragraph (d)(1) or (d)(2) of this AD:
(1) Revise the Limitations section to include appropriate
operating procedures relative to operation of the modification
required by paragraph (c) of this AD. These operating procedures
must be approved by the Manager, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Or
(2) Revise the Limitations section to include the following
operating procedures relative to the operation of the modification
required by paragraph (c) of this AD. This may be accomplished by
inserting a copy of this AD in the AFM.
``Use of Bleed Air Anti-Ice System
Caution
The Model DC-9-10 series airplane has a wing design with no
leading edge high lift devices, such as slats. Wings without leading
edge devices are particularly susceptible to loss of lift due to
wing icing. Minute amounts of ice or other contamination (equivalent
to medium grit sandpaper) on the leading edges or wing upper
surfaces can cause a significant reduction in the stall angle-of-
attack. This can increase the stall speed up to 30 knots. The
increased stall speed can be well above the stall warning (stick
shaker) activation speed.
[End Of Cautionary Note]
The bleed air anti-ice system must be on whenever icing
conditions exist or are anticipated, when on the ground, until
immediately prior to commencement of takeoff roll.''
(e) 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, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Los Angeles ACO.
Note: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(f) Special flight permits may be issued in accordance with FAR
21.197 and 21.199 to operate the airplane to a location where the
requirements of this AD can be accomplished.
(g) The installation of a supplemental on-ground wing leading
edge ice protection system shall be done in accordance with
McDonnell Douglas DC-9 Service Bulletin 30-65, dated October 8,
1992. 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, as of July 22, 1993 (58 FR 33898, June 22, 1993). Copies
may be obtained from McDonnell Douglas Corporation, P.O. Box 1771,
Long Beach, California 90846-1771, Attention: Business Unit Manager,
Technical Administrative Support, Dept. L51, Mail Code 2-98. Copies
may be inspected at the FAA, Transport Airplane Directorate, 1601
Lind Avenue, SW., Renton, Washington; or at the FAA, Transport
Airplane Directorate, Los Angeles Aircraft Certification Office
(ACO), 3229 East Spring Street, Long Beach, California; or at the
Office of the Federal Register, 800 North Capitol Street, NW., suite
700, Washington, DC.
(h) This amendment becomes effective on July 22, 1993.
Issued in Renton, Washington, on February 28, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-4952 Filed 3-3-94; 8:45 am]
BILLING CODE 4910-13-U
