DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39 [63 FR 8078 NO. 32 02/18/98]
[Docket No. 97-NM-173-AD; Amendment 39-10347; AD 98-04-35]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-3 and
DC-4 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
SUMMARY: This amendment adopts a new airworthiness
directive (AD), applicable to all McDonnell Douglas Model
DC-3 and DC-4 series airplanes, that requires revising the
Airplane Flight Manual (AFM) to specify procedures that
would prohibit flight in severe icing conditions (as
determined by certain visual cues), limit or prohibit the
use of various flight control devices while in severe icing
conditions, and provide the flight crew with recognition
cues for, and procedures for exiting from, severe icing
conditions. This amendment is prompted by results of a
review of the requirements for certification of the airplane
in icing conditions, new information on the icing
environment, and icing data provided currently to the flight
crews. The actions specified by this AD are intended to
minimize the potential hazards associated with operating the
airplane in severe icing conditions by providing more
clearly defined procedures and limitations associated with
such conditions.
EFFECTIVE DATE: March 25, 1998.
ADDRESSES: Information pertaining to this rulemaking action
may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601
Lind Avenue, SW., Renton, Washington; or at the FAA,
Transport Airplane Directorate, Los Angeles Aircraft
Certification Office, 3960 Paramount Boulevard, Lakewood,
California.
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: A proposal to amend part 39 of
the Federal Aviation Regulations (14 CFR part 39) to include
an airworthiness directive (AD) that is applicable to all
McDonnell Douglas Model DC-3 and DC-4 series airplanes was
published in the Federal Register on September 16, 1997 (62
FR 48553). That action proposed to require revising the
Limitations Section of the FAA-approved Airplane Flight
Manual (AFM) to specify procedures that would:
• require flight crews to immediately request priority
handling from Air Traffic Control to exit severe icing
conditions (as determined by certain visual cues);
• prohibit flight in severe icing conditions (as
determined by certain visual cues);
• prohibit use of the autopilot when ice is formed aft
of the protected surfaces of the wing, or when an unusual
lateral trim condition exists; and
• require that all icing wing inspection lights be
operative prior to flight into known or forecast icing
conditions at night.
That action also proposed to require revising the Normal
Procedures Section of the FAA-approved AFM to specify
procedures that would:
• limit the use of the flaps and prohibit the use of
the autopilot when ice is observed forming aft of the
protected surfaces of the wing, or if unusual lateral trim
requirements or autopilot trim warnings are encountered; and
• provide the flight crew with recognition cues for,
and procedures for exiting from, severe icing conditions.
Comments
Interested persons have been afforded an opportunity to
participate in the making of this amendment. Due
consideration has been given to the following comments
received.
In addition to the proposed rule described previously,
in September 1997, the FAA issued 24 other similar proposals
that address the subject unsafe condition on various
airplane models (see below for a listing of all 24 proposed
rules). These 24 proposals also were published in the
Federal Register on September 16, 1997. This final rule
contains the FAA's responses to all relevant public comments
received for each of these proposed rules.
Federal
Manufacturer/ Register
Docket Number Airplane Model Citation
97-CE-49-AD Aerospace Technologies 62 FR 48520
of Australia
Models N22B and N24A
97-CE-50-AD Harbin Aircraft Mfg. 62 FR 48513
Corporation Model Y12 IV
97-CE-51-AD Partenavia Costruzioni 62 FR 48524
Aeronauticas, S.p.A. Models
P68, AP68TP 300, AP68TP 600
97-CE-52-AD Industrie Aeronautiche 62 FR 48502
Meccaniche Rinaldo Piaggio
S.p.A. Model P-180
97-CE-53-AD Pilatus Aircraft Ltd. 62 FR 48499
Models PC-12 and PC-12/45
97-CE-54-AD Pilatus Britten-Norman Ltd. 62 FR 48538
Models BN-2A, BN-2B,
and BN-2T
97-CE-55-AD SOCATA - Groupe 62 FR 48506
Aerospatiale Model TBM-700
97-CE-56-AD Aerostar Aircraft Corporation 62 FR 48481
Models PA-60-600, -601,
-601P, -602P, and -700P
97-CE-57-AD Twin Commander Aircraft 62 FR 48549
Corporation Models 500, -500-A,
-500-B, -500-S, -500-U, -520, -560,
-560-A, -560-E, -560-F, -680, -680-E,
-680FL(P), -680T, -680V, -680W,
-681, -685, -690, -690A, -690B, -690C,
-690D, -695, -695A, -695B, and 720
97-CE-58-AD Raytheon Aircraft Company 62 FR 48517
(formerly known as Beech
Aircraft Corporation)
Models E55, E55A, 58, 58A, 58P,
58PA, 58TC, 58TCA, 60 series,
65-B80 series, 65-B-90 series,
90 series, F90 series, 100 series,
300 series, and B300 series
97-CE-59-AD Raytheon Aircraft Company 62 FR 48531
(formerly known as Beech
Aircraft Corporation) Model 2000
97-CE-60-AD The New Piper Aircraft, Inc. 62 FR 48542
Models PA-46 -310P and
PA-46-350P
97-CE-61-AD The New Piper Aircraft, Inc. 62 FR 52294
Models PA-23, PA-23-160,
PA-23-235, PA-23-250, PA-E23-250,
PA-30, PA-39, PA-40, PA-31,
PA-31-300, PA-31-325, PA-31-350,
PA-34-200, PA-34-200T, PA-34-220T,
PA-42, PA-42-720, PA-42-1000
97-CE-62-AD Cessna Aircraft Company 62 FR 48535
Models P210N, T210N, P210R,
and 337 series
97-CE-63-AD Cessna Aircraft Company 62 FR 48528
Models T303, 310R, T310R, 335,
340A, 402B, 402C, 404, F406, 414,
414A, 421B, 421C, 425, and 441
97-CE-64-AD SIAI-Marchetti S.r.I. (Augusta) 62 FR 48510
Models SF600 and SF600A
97-NM-170-AD Cessna Aircraft Company 62 FR 48560
Models 500, 501, 550, 551,
and 560 series
97-NM-171-AD Sabreliner Corporation 62 FR 48556
Models 40, 60, 70, and 80 series
97-NM-172-AD Gulfstream Aerospace 62 FR 48563
Model G-159 series
97-NM-173-AD McDonnell Douglas 62 FR 48553
Models DC-3 and DC-4 series
97-NM-174-AD Mitsubishi Heavy Industries 62 FR 48567
Models YS-11 and YS-11A series
97-NM-175-AD Frakes Aviation 62 FR 48577
Models G-73 (Mallard) and
G-73T series
97-NM-176-AD Lockheed 62 FR 48574
Models L-14 and L-18 series
97-NM-177-AD Fairchild 62 FR 48570
Models F27 and FH227 series
Comment 1. Unsubstantiated Unsafe Condition for This Model
One commenter suggests that the AD’s were developed in
response to a suspected contributing factor of an accident
involving an airplane type unrelated to the airplanes
specified in the proposal. The commenter states that these
proposals do not justify that an unsafe condition exists or
could develop in a product of the same type design.
Therefore, the commenter asserts that the proposal does not
meet the criteria for the issuance of an AD as specified in
the Federal Aviation Regulations (14 CFR part 39).
The FAA does not concur. As stated in the Notice of
Proposed Rulemaking (NPRM), the FAA has identified an unsafe
condition associated with operating the airplane in severe
icing conditions. As stated in the preamble to the
proposal, the FAA has not required that airplanes be shown
to be capable of operating safely in icing conditions
outside the certification envelope specified in Appendix C
of part 25 of the Federal Aviation Regulations (14 CFR part
25). This means that any time an airplane is flown in icing
conditions for which it is not certificated, there is a
potential for an unsafe condition to exist or develop and
the flight crew must take steps to exit those conditions
expeditiously. Further, the FAA has determined that flight
crews are not currently provided with adequate information
necessary to determine when an airplane is operating in
icing conditions for which it is not certificated or what
action to take when such conditions are encountered. The
absence of this information presents an unsafe condition
because without that information, a pilot may remain in
potentially hazardous icing conditions. This AD addresses
the unsafe condition by requiring AFM revisions that provide
the flight crews with visual cues to determine when icing
conditions have been encountered for which the airplane is
not certificated, and by providing procedures to safely exit
those conditions.
Further, in the preamble of the proposed rule, the FAA
discussed the investigation of roll control anomalies to
explain that this investigation was not a complete
certification program. The testing was designed to examine
only the roll handling characteristics of the airplane in
certain droplets the size of freezing drizzle. The testing
was not a certification test to approve the airplane for
flight into freezing drizzle. The results of the tests were
not used to determine if this AD is necessary, but rather to
determine if design changes were needed to prevent a
catastrophic roll upset. The roll control testing and the
AD are two unrelated actions.
Additionally, in the preamble of the proposed rule, the
FAA acknowledged that the flight crew of any airplane that
is certificated for flight icing conditions may not have
adequate information concerning flight in icing conditions
outside the icing envelope. However, in 1996, the FAA found
that the specified unsafe condition must be addressed as a
higher priority on airplanes equipped with pneumatic deicing
boots and unpowered roll control systems. These airplanes
were addressed first because the flight crew of an airplane
having an unpowered roll control system must rely solely on
physical strength to counteract roll control anomalies,
whereas a roll control anomaly that occurs on an airplane
having a powered roll control system need not be offset
directly by the flight crew. The FAA also placed a priority
on airplanes that are used in regularly scheduled passenger
service. The FAA has previously issued AD’s to address
those airplanes. Since the issuance of those AD’s, the FAA
has determined that similar AD’s should be issued for
similarly equipped airplanes that are not used in regularly
scheduled passenger service.
Comment 2. AD is Inappropriate to Address Improper
Operation of the Airplane
One commenter requests that the proposed AD be withdrawn
because an unsafe condition does not exist within the
airplane. Rather, the commenter asserts that the unsafe
condition is the improper operation of the airplane. The
commenter further asserts that issuance of an AD is an
inappropriate method to address improper operation of the
airplane.
The FAA does not concur. The FAA has determined that an
unsafe condition does exist as explained in the proposed
notice and discussed previously. As specifically addressed
in Amendment 39-106 of part 39 of the Federal Aviation
Regulations (14 CFR part 39), the responsibilities placed on
the FAA statute (49 U.S.C., formerly the Federal Aviation
Act), justify allowing AD’s to be issued for unsafe
conditions however and wherever found, regardless of whether
the unsafe condition results from maintenance, design
defect, or any other reason.
This same commenter considers that part 91 (rather than
part 39) of the Federal Aviation Regulations (14 CFR part
91) is the appropriate regulation to address the problems of
icing encounters outside of the limits for which the
airplane is certificated. Therefore, the commenter requests
that the FAA withdraw the proposal.
The FAA does not concur. Service experience
demonstrates that flight in icing conditions that are
outside the icing certification envelope does occur. Apart
from the visual cues provided in these final rules, there is
no existing method provided to the flight crews to identify
when the airplane is in a condition that exceeds the icing
certification envelope. Because this lack of awareness may
create an unsafe condition, the FAA has determined that it
is appropriate to issue an AD to require revision of the AFM
to provide this information.
One commenter asserts that while it is prudent to advise
and routinely remind the pilots about the hazards associated
with flight into known or forecast icing conditions, the
commenter is opposed to the use of an AD to accomplish that
function. The commenter states that pilots’ initial and bi-
annual flight checks are the appropriate vehicles for
advising the pilots of such hazards, and that such
information should be integrated into the training syllabus
for all pilot training.
The FAA does not concur that substituting advisory
material and mandatory training for issuance of an AD is
appropriate. The FAA acknowledges that, in addition to the
issuance of an AD, information specified in the revision to
the AFM should be integrated into the pilot training
syllabus. However, the development and use of such advisory
materials and training alone are not adequate to address the
unsafe condition. The only method of ensuring that certain
information is available to the pilot is through
incorporation of the information into the Limitations
Section of the AFM. The appropriate vehicle for requiring
such revision of the AFM is issuance of an AD. No change is
necessary to the final rule.
Comment 3. Inadequate Visual Cues
One commenter provides qualified support for the AD.
The commenter notes that the recent proposals are identical
to the AD’s issued about a year ago. Although the commenter
supports the intent of the AD’s as being appropriate and
necessary, the commenter states that it is unfortunate that
the flight crew is burdened with recognizing icing
conditions with visual cues that are inadequate to determine
certain icing conditions. The commenter points out that,
for instance, side window icing (a very specific visual cue)
was determined to be a valid visual cue during a series of
icing tanker tests on a specific airplane; however, later
testing of other models of turboprop airplanes revealed that
side window icing was invalid as a visual cue for
identifying icing conditions outside the scope of
Appendix C.
The FAA does not concur with the commenters’ request to
provide more specific visual cues. The FAA finds that the
value of visual cues has been substantiated during
in-service experience. Additionally, the FAA finds that the
combined use of the generic cues provided and the effect of
the final rules in increasing the awareness of pilots
concerning the hazard of operating outside of the
certification icing envelope will provide an acceptable
level of safety. Although all of the cues may not be
exhibited on a particular model, the FAA considers that at
least some of the cues will be exhibited on all of the
models affected by this AD. For example, some airplanes may
not have side window cues in freezing drizzle, but would
exhibit other cues, (such as accumulation of ice aft of the
protected area) under those conditions. For these reasons,
the FAA considers that no changes regarding visual cues are
necessary to the final rule. However, for those operators
that elect to identify airplane-specific visual cures, the
FAA would consider a request for approval of an alternative
method of compliance, in accordance with the provisions of
this AD.
Comment 4. Request for Research and Use of Wing-Mounted Ice
Detectors
One commenter requests that wing-mounted ice detectors,
which provide real-time icing severity information (or
immediate feedback) to flight crews, continue to be
researched and used throughout the fleet. The FAA infers
from this commenter’s request that the commenter asks that
installation of these ice detectors be mandated by the FAA.
While the FAA supports the development of such ice
detectors, the FAA does not concur that installation of
these ice detectors should be required at this time. Visual
cues are adequate to provide an acceptable level of safety;
therefore, mandatory installation of ice detector systems,
in this case, is not necessary to address the unsafe
condition. Nevertheless, because such systems may improve
the current level of safety, the FAA has officially tasked
the Aviation Rulemaking Advisory Committee (ARAC) to develop
a recommendation concerning ice detection. Once the ARAC
has submitted its recommendation, the FAA may consider
further rulemaking action to require installation of such
equipment.
Comment 5. Particular Types of Icing
This same commenter also requests that additional
information be included in paragraph (a) of the AD that
would specify particular types of icing or particular
accretions that result from operating in freezing
precipitation. The commenter asserts that this information
is of significant value to the flightcrew.
The FAA does not concur with the commenter’s suggestion
to specify types of icing or accretion. The FAA has
determined that supercooled large droplets (SLD) can result
in rime ice, mixed (intermediate) ice, and ice with glaze or
clear appearance. Therefore, the FAA finds that no type of
icing can be excluded from consideration during operations
in freezing precipitation, and considers it unnecessary to
cite those types of icing in the AD.
Conclusion
After careful review of the available data, including
the comments noted above, the FAA has determined that air
safety and the public interest require the adoption of the
rule as proposed.
Cost Impact
There are approximately 300 McDonnell Douglas Model DC-3
and DC-4 series airplanes of the affected design in the
worldwide fleet. The FAA estimates that 166 airplanes of
U.S. registry will be affected by this AD, that it will take
approximately 1 work hour 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 $9,960, or $60 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.
In addition, the FAA recognizes that this action may
impose operational costs. However, these costs are
incalculable because the frequency of occurrence of the
specified conditions and the associated additional flight
time cannot be determined. Nevertheless, because of the
severity of the unsafe condition, the FAA has determined
that continued operational safety necessitates the
imposition of the costs.
Regulatory Impact
The regulations adopted herein will 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 final rule
does not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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) 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, 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.
§ 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
98-04-35 MCDONNELL DOUGLAS: Amendment 39-10347. Docket
97-NM-173-AD.
Applicability: All Model DC-3 and DC-4 series
airplanes, 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 minimize the potential hazards associated with
operating the airplane in severe icing conditions by
providing more clearly defined procedures and limitations
associated with such conditions, accomplish the following:
(a) Within 30 days after the effective date of this AD,
accomplish the requirements of paragraphs (a)(1) and (a)(2)
of this AD.
NOTE 2: Operators should initiate action to notify and
ensure that flight crewmembers are apprised of this change.
(1) Revise the FAA-approved Airplane Flight Manual
(AFM) by incorporating the following into the Limitations
Section of the AFM. This may be accomplished by inserting a
copy of this AD in the AFM.
“WARNING
Severe icing may result from environmental conditions
outside of those for which the airplane is certificated.
Flight in freezing rain, freezing drizzle, or mixed
icing conditions (supercooled liquid water and ice
crystals) may result in ice build-up on protected
surfaces exceeding the capability of the ice protection
system, or may result in ice forming aft of the
protected surfaces. This ice may not be shed using the
ice protection systems, and may seriously degrade the
performance and controllability of the airplane.
• During flight, severe icing conditions that exceed
those for which the airplane is certificated shall be
determined by the following visual cues. If one or more
of these visual cues exists, immediately request
priority handling from Air Traffic Control to facilitate
a route or an altitude change to exit the icing
conditions.
- Unusually extensive ice accumulation on the airframe
and windshield in areas not normally observed to collect
ice.
- Accumulation of ice on the upper surface of the wing
aft of the protected area.
- Accumulation of ice on the engine nacelles and
propeller spinners farther aft than normally observed.
• Since the autopilot, when installed and operating,
may mask tactile cues that indicate adverse changes in
handling characteristics, use of the autopilot is
prohibited when any of the visual cues specified above
exist, or when unusual lateral trim requirements or
autopilot trim warnings are encountered while the
airplane is in icing conditions.
• All wing icing inspection lights must be operative
prior to flight into known or forecast icing conditions
at night. [NOTE: This supersedes any relief provided
by the Master Minimum Equipment List (MMEL).]”
(2) Revise the FAA-approved AFM by incorporating the
following into the Normal Procedures Section of the AFM.
This may be accomplished by inserting a copy of this AD in
the AFM.
“THE FOLLOWING WEATHER CONDITIONS
MAY BE CONDUCIVE TO SEVERE
IN-FLIGHT ICING:
• Visible rain at temperatures below 0 degrees Celsius
ambient air temperature.
• Droplets that splash or splatter on impact at
temperatures below 0 degrees Celsius ambient air
temperature.
PROCEDURES FOR EXITING
THE SEVERE ICING ENVIRONMENT:
These procedures are applicable to all flight phases
from takeoff to landing. Monitor the ambient air
temperature. While severe icing may form at
temperatures as cold as -18 degrees Celsius, increased
vigilance is warranted at temperatures around freezing
with visible moisture present. If the visual cues
specified in the Limitations Section of the AFM for
identifying severe icing conditions are observed,
accomplish the following:
• Immediately request priority handling from Air
Traffic Control to facilitate a route or an altitude
change to exit the severe icing conditions in order to
avoid extended exposure to flight conditions more severe
than those for which the airplane has been certificated.
• Avoid abrupt and excessive maneuvering that may
exacerbate control difficulties.
• Do not engage the autopilot.
• If the autopilot is engaged, hold the control wheel
firmly and disengage the autopilot.
• If an unusual roll response or uncommanded roll
control movement is observed, reduce the angle-of-
attack.
• Do not extend flaps when holding in icing conditions.
Operation with flaps extended can result in a reduced
wing angle-of-attack, with the possibility of ice
forming on the upper surface further aft on the wing
than normal, possibly aft of the protected area.
• If the flaps are extended, do not retract them until
the airframe is clear of ice.
• Report these weather conditions to Air Traffic
Control.”
(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 (ACO), FAA, 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 3: 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.
(d) This amendment becomes effective on March 25, 1998.
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.
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