[Federal Register Volume 64, Number 222 (Thursday, November 18, 1999)]
[Proposed Rules]
[Pages 62993-62995]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30150]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-139-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Models DC-3 and DC-4
Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of
comment period.
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SUMMARY: This document revises an earlier proposed airworthiness
directive (AD), applicable to certain McDonnell Douglas Models DC-3 and
DC-4 series airplanes, that would have required revising the Airplane
Flight Manual (AFM) to include requirements for activation of the
airframe pneumatic deicing boots. That proposal was prompted by reports
of inflight incidents and an accident that occurred in icing conditions
where the airframe pneumatic deicing boots were not activated. This new
action revises the proposed rule by adding an inspection to determine
the type of pneumatic deicing boots, and requiring the AFM change only
for those airplanes equipped with ``modern'' boots. The actions
specified by this new proposed AD are intended to ensure that
flightcrews activate the pneumatic wing and tail deicing boots at the
first signs of ice accumulation. This action will prevent reduced
controllability of the aircraft due to adverse aerodynamic effects of
ice adhering to the airplane prior to the first deicing cycle.
DATES: Comments must be received by December 13, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-139-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
This information may be examined at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA,
Transport Airplane Directorate, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137.
FOR FURTHER INFORMATION CONTACT: Albert Lam, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5346;
fax (562) 627-5210.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 99-NM-139-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 99-NM-139-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to
certain McDonnell Douglas Models DC-3 and DC-4 series airplanes, was
published as a notice of proposed rulemaking (NPRM) in the Federal
Register on July 16, 1999 (64 FR 38335). That NPRM would have required
revising the Airplane Flight Manual (AFM) to include requirements for
activation of
[[Page 62994]]
the airframe pneumatic deicing boots. That NPRM was prompted by reports
of inflight incidents and an accident that occurred in icing conditions
where the airframe pneumatic deicing boots were not activated. The
actions specified by that proposed AD are intended to ensure that
flightcrews activate the pneumatic wing and tail deicing boots at the
first signs of ice accumulation. Such ice accumulation, if not
corrected, could result in reduced controllability of the aircraft due
to adverse aerodynamic effects of ice adhering to the airplane prior to
the first deicing cycle.
Distinction Between ``Older'' and ``Modern'' Boots
For the purposes of this supplemental NPRM, the FAA considers that
a definition of the terms ``older'' and ``modern'' pneumatic deicing
boots is necessary. ``Modern'' pneumatic boot systems may be
characterized by short segmented, small diameter tubes, which are
operated at relatively high pressures [18-23 pounds per square inch
(psi)] by excess bleed air that is provided by turbine engines.
``Older'' pneumatic boot systems may be characterized by long,
uninterrupted, large diameter tubes, which were operated at low
pressures by engine driven pneumatic pumps whose pressure varied with
engine revolutions per minute (rpm). This low pressure coupled with
long and large diameter tubes caused early de-ice systems to have very
lengthy inflation and deflation cycles and dwell times. (Dwell time is
the period of time that the boot remains fully expanded following the
completion of the inflation cycle until the beginning of the deflation
cycle.) The FAA has specified these definitions in a new Note 1 in the
final rule.
Actions Since Issuance of Previous Proposal
Due consideration has been given to the comments received in
response to the NPRM:
Two commenters request that the proposed rules applying to
Gulfstream Model G-159 series airplanes and McDonnell Douglas Model DC-
3 and DC-4 series airplanes be withdrawn. Both commenters state that
those airplane models do not meet the common definition of the word
``modern.'' One commenter states that the current AFM specifically
directs the flight crew to wait for \1/2\-inch of ice before activating
the boots. Further, the commenter asserts that the current procedure
was developed during certification and is the basis for the airplane's
approval for flight into known icing. Additionally, the commenters
assert that the in-service safety records for more than 40 years
indicate that the existing procedures are appropriate for these
airplanes. The commenters conclude that the proposed AFM revision is in
direct opposition to the certification findings.
As discussed in the original NPRM, the FAA acknowledges that early
activation of the ``older'' pneumatic deicing boots may create the
hazard of ice bridging on the ``older'' systems. The FAA considers that
``older'' boots may be susceptible to ice bridging because the boots
operate at lower pressure and have larger diameter tubes. The FAA
concurs that requiring the activation of the boots at the first sign of
icing may actually introduce an unsafe condition on those airplanes.
In order to address this issue, the FAA is taking the following
steps. First, to accommodate certain McDonnell Douglas Model DC-3 and
DC-4 series airplanes that may be equipped with the ``older'' pneumatic
deicing boot system, the FAA is issuing this supplemental Notice of
Proposed Rulemaking (NPRM). This supplemental NPRM proposes to require
an inspection to determine which type of pneumatic deicing boots are
installed on the airplanes, and to require operation of the boots at
the first sign of ice accretion if the airplanes have been retrofitted
with ``modern'' boots. Second, for aircraft with ``older'' pneumatic
boots installed, the FAA will continue to investigate other solutions
to the unsafe condition of reduced handling qualities or
controllability of the airplane due to ice accumulations on the
protected surfaces. The FAA may consider further rulemaking if it is
determined that there is an existing unsafe condition on those
airplanes equipped with ``older'' pneumatic deicing boot systems.
Additionally, the FAA is issuing a similar supplemental NPRM to
accommodate certain Gulfstream Model G-159 series airplanes that may be
equipped with ``older'' pneumatic deicing boot systems.
In response to the commenter's assertion that existing procedures
are appropriate for these airplanes, the FAA has reviewed the icing-
related incident history of certain airplanes, and has determined that
icing incidents may have occurred because pneumatic deicing boots were
not activated at the first evidence of ice accretion. As a result, the
handling qualities or the controllability of the airplane may have been
reduced due to the accumulated ice. In the previous NPRM, the FAA also
discussed an accident that occurred as a result of the failure of the
flight crew to activate the wing and tail pneumatic deicing boots.
Although there may have been no reported cases of incidents or
accidents on a specific airplane model, the potential still exists for
reduced controllability of all airplanes equipped with pneumatic
deicing boots due to adverse aerodynamic effects of ice adhering to the
airplane. This supplemental NPRM addresses that unsafe condition.
Conclusion
Since this change expands the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
Cost Impact
The FAA estimates that 166 airplanes of U.S. registry would be
affected by this proposed AD.
The FAA estimates that it would take approximately 2 work hours per
airplane to accomplish the proposed actions, at the average labor rate
of $60 per work hour. Based on these figures, the cost impact of the
proposed AD on U.S. operators is estimated to be $19,920, or $120 per
airplane.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the proposed requirements of
this AD action, and that no operator would accomplish those actions in
the future if this AD were not adopted.
Regulatory Impact
The regulations proposed herein would not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by
[[Page 62995]]
contacting the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
McDonnell Douglas: Docket 99-NM-139-AD.
Applicability: Models DC-3 and DC-4 series airplanes equipped
with pneumatic deicing boots, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure that flightcrews activate the wing and tail pneumatic
deicing boots at the first signs of ice accumulation on the
airplane, accomplish the following:
Note 1: For the purposes of this AD, the following definitions
of ``older'' and ``modern'' apply:
``Modern'' pneumatic boot systems may be characterized by short
segmented, small diameter tubes, which are operated at relatively
high pressures [18-23 pounds per square inch (psi)] by excess bleed
air that is provided by turbine engines. ``Older'' pneumatic boot
systems may be characterized by long, uninterrupted, large diameter
tubes, which were operated at low pressures by engine driven
pneumatic pumps whose pressure varied with engine revolutions per
minute (rpm). This low pressure coupled with long and large diameter
tubes caused early de-ice systems to have very lengthy inflation and
deflation cycles and dwell times. (Dwell time is the period of time
that the boot remains fully expanded following the completion of the
inflation cycle until the beginning of the deflation cycle.)
(a) Within 10 days after the effective date of this AD: Perform
a visual inspection to determine if the type of pneumatic deicing
boots installed is either ``older'' or ``modern'' boots.
(1) For those airplanes equipped with ``older'' pneumatic
deicing boots, no further action is required by this AD.
(2) For those airplanes equipped with ``modern'' pneumatic
deicing boots, within 10 days after the inspection required by
paragraph (a) of this AD: Revise the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) to include the following
requirements for activation of the ice protection systems. This may
be accomplished by inserting a copy of this AD in the AFM.
`` Except for certain phases of flight where the AFM
specifies that deicing boots should not be used (e.g., take-off,
final approach, and landing), compliance with the following is
required.
Wing and Tail Leading Edge Pneumatic Deicing Boot
System, if installed, must be activated:
--At the first sign of ice formation anywhere on the aircraft, or
upon annunciation from an ice detector system, whichever occurs
first; and
--The system must either be continued to be operated in the
automatic cycling mode, if available; or the system must be manually
cycled as needed to minimize the ice accretions on the airframe.
The wing and tail leading edge pneumatic deicing boot
system may be deactivated only after leaving icing conditions and
after the airplane is determined to be clear of ice.''
(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, Los Angeles Aircraft Certification
Office, Transport Airplane Directorate. The request shall be
forwarded through an appropriate FAA Operations Inspector, who may
add comments and then send it to the Manager, Los Angeles ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(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.
Issued in Renton, Washington, on November 10, 1999.
John J. Hickey,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-30150 Filed 11-17-99; 8:45 am]
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