[Federal Register Volume 60, Number 201 (Wednesday, October 18, 1995)]
[Proposed Rules]
[Pages 53883-53888]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25836]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-146-AD]
Airworthiness Directives; Aerospatiale Model ATR-42 and ATR-72
Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to all Aerospatiale Model ATR-
42 and ATR-72 series airplanes. Unless modifications are accomplished
or alternative procedures and training are adopted, that AD currently
prohibits operation of the airplane in certain icing conditions, and
requires restrictions on the use of the autopilot in certain
conditions. That AD was prompted by an FAA determination that, during
flight in certain icing conditions, and with the airplane in a specific
flight configuration, a ridge of ice can form on the wing and cause an
interruption in the airflow over the ailerons, aileron deflection, and
resultant lateral control forces. The actions specified by that AD are
intended to prevent a roll upset from which the flight crew may be
unable to recover. This action would add requirements for modification
of the deicing boots on the leading edge of the wing and various
follow-on actions.
DATES: Comments must be received by November 28, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-146-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.
The service information referenced in the proposed rule may be
obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex
03, France. This information may be examined at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Gary Lium, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-1112; fax (206) 227-1149.
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
[[Page 53884]]
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 95-NM-146-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-103, Attention: Rules
Docket No. 95-NM-146-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On December 9, 1994, the FAA issued telegraphic AD T94-25-51,
applicable to all Aerospatiale Model ATR-42 and ATR-72 series
airplanes, to address an unsafe condition related to potential hazards
associated with operation of those airplanes in icing conditions. That
AD required an operational limitation that prohibits operation of the
airplane when icing conditions [as defined in the Airplane Flight
Manual (AFM)] are forecast or reported. It also required restrictions
on the use of the autopilot in inadvertent icing encounters, when the
airplane is operated in moderate or greater turbulence, or whenever any
unusual lateral trim situation is observed.
That AD action was prompted by data obtained following an accident
involving a Model ATR-72 series airplane that occurred when the
airplane was enroute from Indianapolis to Chicago. The accident
occurred during the initial descent for approach to Chicago. The
airplane had been in a holding pattern for more than 30 minutes with
flaps at the 15-degree position; icing conditions and turbulence were
reported in the area.
The official cause of the accident has not been determined.
However, preliminary information from the accident investigation
indicates that, immediately after the autopilot disconnected, at an
indicated airspeed of approximately 185 knots, the ailerons abruptly
deflected in the right-wing-down direction, and the airplane entered an
abrupt roll to the right, which was not corrected before the airplane
impacted the ground.
Results of Flight Tests Conducted at Edwards Air Force Base,
California
Prior to the issuance of telegraphic AD T94-25-51, Aerospatiale
conducted wind tunnel and ground tests in Toulouse, France. Subsequent
to the issuance of that AD, Aerospatiale contracted with the United
States Air Force (USAF) to conduct a series of flight tests at Edwards
Air Force Base, California. The test program was developed in
conjunction with the National Transportation Safety Board (NTSB),
National Aeronautics and Space Administration (NASA), the USAF, the
FAA, and the Direction Generale de l'Aviation Civile (DGAC), which is
the airworthiness authority for France.
During these tests, a Model ATR-72 series airplane flew in close
formation behind an ``icing tanker,'' which is a specially modified
aerial refueling airplane designed to create icing conditions by
spraying supercooled water droplets on a test airplane during flight.
Appendix C of part 25 of the Federal Aviation Regulations (14 CFR part
25) defines droplet diameters, liquid water content, temperature, and
horizontal extent parameters for testing leading to approval of flight
in icing conditions. Water droplet diameters specified in part 25 of
the Federal Aviation Regulations (FAR) for certification of transport
category airplanes, and larger droplets well outside the diameters
specified in part 25 of the FAR (commonly referred to as ``freezing
rain or freezing drizzle''), were sprayed onto the leading edges of the
outer wing and on other airplane surfaces to determine ice accretion
characteristics of the various diameter droplets. Droplet diameters
larger than those specified in part 25 of the FAR were tested since
meteorological evidence exists indicating that the accident airplane
encountered such large droplets (freezing rain or freezing drizzle)
prior to the accident.
Results of data from the numerous flight tests conducted revealed
the following significant findings:
--Ice accretion characteristics of the normal diameter droplets, as
specified in the FAR, were entirely satisfactory. This confirmed that
Model ATR-42 and ATR-72 series airplanes comply fully with performance
requirements relating to the icing envelope specified in part 25 of the
FAR for certification of these airplanes.
--Results of additional testing that was conducted with large water
droplets (outside certification standards) revealed that it is possible
for ice to accrete aft of the wing boot surface during a 17-minute
exposure to the tanker spray when the aircraft operates with the flaps
set at 15 degrees. Results of flight tests conducted with the flaps set
at 15 degrees indicated that a spanwise ridge could disrupt the flow of
air over the aileron when the flaps are retracted to the zero-degree
position. This interruption of airflow caused an uncommanded aileron
deflection and resultant unusual lateral control forces. However,
during the tests conducted, the forces required to control the aircraft
were within limits specified by the FAR.
--Exposure to freezing rain or freezing drizzle on the forward side
windows of the cockpit produced ice on a substantial part of the
forward side windows. This ice accretion on the forward side windows
does not appear when the airplane is flying in the icing conditions
defined in part 25 of the FAR. This characteristic ice accretion begins
to form within 30 seconds of the beginning of the encounter with
freezing rain or freezing drizzle. Additionally, test data indicate
that the flight crew can observe the accumulation of ice on the forward
side windows at least several minutes before a significant amount of
ice accumulates on the wings.
The cause of the accident is still under investigation. However, in
light of the findings discussed previously, the FAA has determined that
if a Model ATR-42 or ATR-72 series airplane is in flight with the flaps
set at 15 degrees during freezing rain or freezing drizzle, an unusual
ridge of ice on the wing (aft of the ice protection boots) can accrete.
This ridge can interrupt the airflow over the ailerons when the flaps
are retracted to the zero-degree position. This interruption of airflow
can cause an aileron deflection and resultant unusual lateral control
forces. In actual operations, these unusual forces may result in a roll
upset from which the flight crew may be unable to recover.
Explanation of the Provisions of AD 95-02-51
In an effort to break the chain of events that may lead to an
aircraft roll upset, the manufacturer developed a set of procedures to
be followed if the airplane should inadvertently encounter freezing
rain or freezing drizzle conditions. These procedures were based on
results of the tests conducted at Edwards Air Force Base. These
procedures prohibit dispatch into or operation in known or forecast
freezing rain or freezing drizzle, provide the
[[Page 53885]]
flight crew with a means to identify inadvertent encounters with
freezing rain and freezing drizzle conditions, and describe appropriate
corrective actions. Accomplishment of these procedures will ensure safe
operation of the airplane while operating in all icing conditions,
including inadvertent encounters with freezing rain or freezing
drizzle.
These procedures were incorporated into several documents and
related actions, which formed the basis for the FAA to expand operation
of Model ATR-42 and ATR-72 series airplanes beyond that defined in
telegraphic AD T94-25-51. Subsequently, on February 13, 1995, the FAA
issued AD 95-02-51, amendment 39-9152 (60 FR 9616, February 21, 1995)
to mandate the procedures developed by the manufacturer and approved by
the FAA. Unless modifications are accomplished or alternative
procedures and training are adopted, that AD continues to require an
operational limitation that prohibits operation of the airplane when
icing conditions (as defined in the AFM) are forecast or reported; and
restrictions on the use of the autopilot in inadvertent icing
encounters, when the airplane is operated in moderate or greater
turbulence, or whenever any unusual lateral trim situation is observed.
That AD also permits, as an interim measure prior to installation of an
FAA-approved modification, operation of the airplane into icing
conditions, provided that certain actions have been accomplished, as
follows:
1. The FAA-approved AFM must be revised to incorporate ATR-42 AFM
Temporary Revision 18, dated January 10, 1995 (for Model ATR-42 series
airplanes); or ATR-72 AFM Temporary Revision 14, dated January 10, 1995
(for Model ATR-72 series airplanes).
2. All Model ATR-42 and ATR-72 flight crew members must attend an
FAA-approved training course prior to flight in known or forecast icing
conditions. This training course provides instruction in the
recognition of characteristic ice accretion on the cockpit forward side
windows. This course also defines the procedures designed to escape
freezing rain and freezing drizzle conditions and to minimize the
hazard posed by flight in freezing rain or freezing drizzle. Documents
used in this training course include the following: ATR Icing
Conditions Procedures Brochure, Version 1.0 or 2.0; ATR Technical
Background Paper, Version 1.0, dated January 6, 1995; Flight Crew
Operation Manual, Revision 20, dated January 11, 1995 (for Model ATR-42
series airplanes); and Flight Crew Operation Manual, Revision 12, dated
January 11, 1995 (for Model ATR-72 series airplanes).
3. Operators must establish an FAA-approved system to provide
forecasts and reports of freezing rain and freezing drizzle at enroute
altitudes along the route of flight and at all airports considered in
the flight planning process.
4. Operators of Model ATR-72 series airplanes must install ATR
Modification Number 4213 to eliminate the multi-function computer
inhibition against flap extension. The modification permits movement of
the flaps above limit speed to give crews more operational discretion
in an emergency.
That AD also provides for an optional terminating action, which, if
accomplished, would terminate the requirements of the AD. The optional
terminating action, which must be approved by the FAA, involves
installing a modification that precludes the formation of hazardous ice
accumulation during flight in freezing rain or freezing drizzle
conditions. The AD requires that, upon accomplishment of the optional
terminating action, ATR Modification Number 4213 must be removed from
Model ATR-72 series airplanes.
The expanded operation provided by AD 95-02-51 includes the
resumption of dispatch of the airplane into or operation in known or
forecast icing conditions. (However, as specified in the AFM revisions
cited in that AD, flight into known or forecast freezing drizzle or
freezing rain conditions continues to be prohibited.)
The procedures provided by AD 95-02-51 were permitted as an interim
measure to allow resumption of normal flight operations in icing
conditions until June 1, 1995, at which time an FAA-approved
modification was to have been developed, tested, approved, and
installed. The AD specifies that if such a modification was not
installed by June 1, 1995, operation of the airplane when icing
conditions are forecast or reported would again be prohibited and
restrictions on the use of the autopilot in certain conditions would
again be required.
Explanation of a Letter to Affected Operators
While AD 95-02-51 was being developed, the manufacturer was
developing certain modifications to the deicing boots on the leading
edges of the wing. Subsequently, Aerospatiale issued Service Bulletins
ATR42-30-0059, Revision 1, dated April 10, 1995 (for Model ATR-42
series airplanes), and ATR72-30-1023, Revision 1, dated April 10, 1995
(for Model ATR-72 series airplanes). These service bulletins describe
procedures for modification of the deicing boots by extending the
coverage of the deicing boots on the leading edges of the outer wing.
Accomplishment of the modification will increase the deiced area of the
leading edges of the outer wing. [The Aerospatiale modification numbers
are: 4216 (retrofit) and 4222 (production line), for Model ATR-42
series airplanes; and 4215 (retrofit) and 4221 (production line), for
Model ATR-72 series airplanes. These modifications were approved by the
FAA on March 20, 1995, as type design changes to Model ATR-42 and ATR-
72 series airplanes.]
During development of those modifications and following issuance of
AD 95-02-51, it became clear to the FAA that installation of modified
deicing boots alone would not be sufficient to ensure an acceptable
level of safety. Consequently, the FAA determined that certain existing
flight crew procedures specified currently in AD 95-02-51 must remain
in place and must be used in conjunction with the modified deicing
boots. Further, the FAA recognized that a new AD to mandate
installation of the deicing boots and observation of flight crew
procedures could not be completed before the June 1, 1995, deadline
specified in AD 95-02-51, and that sufficient justification existed to
extend that deadline.
In light of this, the FAA approved an alternative method of
compliance for the requirements of AD 95-02-51 in accordance with the
provisions of paragraph (d) of that AD. This approval is contained in a
letter that was distributed to all operators of the affected airplanes
on May 26, 1995. The approval allowed continued operation of these
airplanes in icing conditions beyond June 1, 1995, provided that
certain additional procedures and restrictions were observed and
modification of the deicing boots, as described previously, was
accomplished.
The specific additional procedures and restrictions specified in
the letter to operators included the following:
1. For Model ATR-72 series airplanes only, Aerospatiale
Modification 4213, ``Flaps Extension Inhibition Above VFE 15 ,'' must
be installed (or remain installed, if already accomplished). Procedures
for accomplishment of the modification are contained in Aerospatiale
Service Bulletin ATR72-27-1039, dated January 12, 1995. The
modification removes the flap movement cutout at speeds greater than
[[Page 53886]]
185 knots to provide flight crews more operational discretion in an
emergency.
2. Flight crew training based on the revised ATR Icing Procedures
Brochure ``Freezing Drizzle: Towards a Better Knowledge and a Better
Protection,'' Issue 1, dated May 11, 1995, must be conducted prior to
flight in icing conditions, and at least annually thereafter, for all
ATR-42 and ATR-72 flight crews. (Training conducted previously in
compliance with AD 95-02-51 may serve as the initial training for
purposes of computing the training interval.)
3. ATR-42 AFM Temporary Revision 20, dated May 1995 (for Model ATR-
42 series airplanes), or ATR-72 AFM Temporary Revision 16, dated May
1995 (for Model ATR-72 series airplanes), must be inserted into the
Limitations Section of the respective AFM. These temporary revisions
specify that dispatch or operation into known freezing rain or freezing
drizzle conditions is prohibited. Once inserted, the AFM revision
required by AD 95-02-51 may be removed.
The FAA determined that observing the procedures and restrictions
outlined above, in addition to installing modified deicing boots, will
provide an additional margin of safety during flight in icing
conditions or during an inadvertent encounter with freezing rain or
freezing drizzle conditions. The FAA also determined that the
procedures identified in the letter to operators will provide the
flight crews with an acceptable means to identify and safely exit those
conditions.
It should be noted that the procedures specified in the letter to
operators are essentially the same as those mandated by AD 95-02-51
with the exception that the letter allows dispatch into forecast (but
not actual or reported) freezing rain or freezing drizzle conditions,
while the AD prohibits such dispatch. Based on its determination that
installing the modifications and observing the operational procedures
and restrictions discussed previously will provide an additional margin
of safety while flying in icing conditions, the FAA finds that the
restriction specified in AD 95-02-51 concerning dispatch into forecast
(but not actual or reported) freezing drizzle or freezing rain
conditions can be eliminated.
Explanation of the Provisions of the Proposed AD
Based on the information discussed previously, and since an unsafe
condition has been identified that is likely to exist or develop on
other airplanes of the same type design registered in the United
States, the FAA proposes to supersede AD 95-02-51 with a new AD with
the following requirements:
Unless modifications are accomplished or alternative procedures and
training are adopted, the proposed AD would continue to prohibit
operation of the airplane in certain icing conditions, and requires
restrictions on the use of the autopilot in certain conditions.
The proposed AD would require installation of the FAA-approved
modification of the deicing boots on the leading edges of the wing,
which must be used in conjunction with certain flight crew procedures.
Accomplishment of the modification and observation of the flight crew
procedures would terminate the requirements of AD 95-02-51, thereby
allowing operation of the airplane in certain icing conditions,
allowing use of the autopilot in certain conditions, and eliminating
the restriction specified in that AD concerning dispatch into forecast
(but not actual or reported) freezing drizzle or freezing rain
conditions.
In addition, the FAA finds that the requirement specified in AD 95-
02-51 for operators to establish an FAA-approved system to provide
forecasts and reports of freezing rain and freezing drizzle at enroute
altitudes along the route of flight and at all airports considered in
the flight planning process must be retained in this proposed AD.
The proposed actions would be required to be accomplished in
accordance with various documents described previously.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this notice to clarify this long-standing requirement.
Cost Estimate
The airplane models affected by this proposed AD action are
manufactured in France and are type certificated for operation in the
United States under the provisions of section 21.29 of the Federal
Aviation Regulations (14 CFR 21.29) and the applicable bilateral
airworthiness agreement.
There are approximately 158 Model ATR-42 and ATR-72 series
airplanes of U.S. registry that would be affected by this proposed AD.
The AFM revision that is currently required by AD 95-02-51 takes
approximately 1 work hour per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the total cost
impact on U.S. operators of the actions currently required is estimated
to be $9,480, or $60 per airplane.
The AFM revision that is proposed in this AD would take
approximately 1 work hour per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the total cost
impact on U.S. operators for the proposed AFM revision is estimated to
be $9,480, or $60 per airplane.
Accomplishment of training concerning the use of icing forecasts
and reports, as proposed in this AD, would be approximately $300,000
annually, or $1,900 per airplane. Accomplishment of flight crew
training based on the Icing Procedures Brochure discussed previously,
as proposed in this AD, would cost approximately $150,000 annually, or
$950 per airplane.
For Model ATR-42 series airplanes, Modification 4216 (or 4222), as
proposed in this AD, would take approximately 52 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Required parts would be supplied by the manufacturer at no cost to
operators. Based on these figures, the total cost impact on U.S.
operators for this proposed modification is estimated to be $492,960,
or $3,120 per airplane.
For Model ATR-72 series airplanes, Modification 4215 (or 4221), as
proposed in this AD, would take approximately 96 work hours per
airplane to accomplish. Required parts for this modification would be
supplied by the manufacturer at no cost to operators. Modification
4213, as proposed in this AD, would take approximately 4 work hours to
accomplish. Required parts would cost approximately $200 per airplane.
The average labor rate for accomplishment of both modifications is $60
per work hour. Based on these figures, the total cost impact on U.S.
operators for these proposed modifications is estimated to be $979,600,
or $6,200 per airplane.
The total cost impact figures discussed above are based on
[[Page 53887]]
assumptions that no operator has yet accomplished any of the current or
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 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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9152 (60 FR
9616, February 21, 1995), and by adding a new airworthiness directive
(AD), to read as follows:
Aerospatiale: Docket 95-NM-146-AD. Supersedes AD 95-02-51, Amendment
39-9152.
Applicability: All Model ATR-42 and ATR-72 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 use the authority
provided in paragraph (d) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To minimize the potential hazards associated with operating in
icing conditions, as defined in the Airplane Flight Manual (AFM),
accomplish the following:
(a) For all airplanes: Except as provided in paragraphs (b) and
(c) of this AD, within 24 hours after receipt of telegraphic AD T94-
25-51, incorporate the following information into the Limitations
Section of the FAA-approved AFM. This may be accomplished by
inserting a copy of this AD in the AFM.
``(1) Operation of the airplane into forecast or reported icing
conditions, as such conditions are defined in the AFM, is
prohibited.
``(2) Use of the autopilot is prohibited during inadvertent
flight in icing conditions, as defined in the AFM, or when the
airplane is operated in moderate or greater turbulence.
``(3) If any unusual lateral trim situations are observed, such
as excessive trim displacement; illumination of the message `RETRIM
ROLL R WING DN' or `RETRIM ROLL L WING DN' on the advisory display
unit (ADU); illumination of the message `AILERON MISTRIM' on the
ADU; or abnormal flight characteristics of the airplane: Disconnect
the autopilot and manually fly the airplane prior to adjusting the
lateral trim. The autopilot may be re-engaged following manual
adjustment of the lateral trim.''
(b) For Model ATR-42 series airplanes: Within 6 months after the
effective date of this AD, accomplish the requirements of paragraph
(b)(1), (b)(2), (b)(3), and (b)(4) of this AD. Accomplishment of the
requirements of this paragraph constitutes terminating action for
the requirements of paragraph (a) of this AD.
(1) Modify the deicing boots on the leading edges of the wing by
accomplishing Aerospatiale Modification 4216 (during retrofit) or
4222 (during production) in accordance with Aerospatiale Service
Bulletin ATR42-30-0059, Revision 1, dated April 10, 1995.
(2) Insert ATR-42 AFM Temporary Revision 20, dated May 1995,
into the Limitations Section of the FAA-approved AFM. Once inserted,
the AFM revision required by AD 95-02-51 may be removed from the
AFM.
Note 2: This may be accomplished by inserting copies of
Temporary Revision 20 in the AFM. When these temporary revisions
have been incorporated into general revisions of the AFM, the
general revisions may be inserted in the AFM, provided the
information contained in the general revisions is identical to that
specified in Temporary Revision 20.
(3) Establish an FAA-approved system to provide forecasts and
reports of freezing rain and freezing drizzle at enroute altitudes
along the route of flight and at all airports considered in the
flight planning process. Training concerning the use of these icing
forecasts and reports shall be accomplished at intervals not to
exceed one year in accordance with Flight Standards Information
Bulletin ``ATR-42 and ATR-72 Airworthiness Directive T95-02-51
Compliance Procedures,'' dated January 11, 1995.
Note 3: Training conducted previously in compliance with the
requirements of AD 95-02-51, amendment 39-9152, may serve as initial
training for purposes of computing the training interval.
(4) Prior to flight in known or forecast icing conditions, and
thereafter at intervals not to exceed one year, conduct flight crew
training based on the revised ATR Icing Procedures Brochure
``Freezing Drizzle: Towards a Better Knowledge and a Better
Protection,'' Issue 1, dated May 11, 1995.
Note 4: Training conducted previously in compliance with the
requirements of AD 95-02-51, amendment 39-9152, may serve as initial
training for purposes of computing the training interval.
(c) For Model ATR-72 series airplanes: Within 6 months after the
effective date of this AD, accomplish the requirements of paragraph
(c)(1), (c)(2), (c)(3), (c)(4), and (c)(5) of this AD.
Accomplishment of the requirements of this paragraph constitutes
terminating action for the requirements of paragraph (a) of this AD.
(1) Modify the deicing boots on the leading edges of the wing by
accomplishing Aerospatiale Modification 4215 (during retrofit) or
4221 (during production) in accordance with Aerospatiale Service
Bulletin ATR72-30-1023, Revision 1, dated April 10, 1995.
(2) Install Aerospatiale Modification 4213, ``Flaps Extension
Inhibition Above VFE 15 deg.,'' in accordance with Aerospatiale
Service Bulletin ATR72-27-1039, dated January 12, 1995.
(3) Insert ATR-72 AFM Temporary Revision 16, dated May 1995,
into the Limitations Section of the FAA-approved AFM. Once inserted,
the AFM revision required by AD 95-02-51 may be removed from the
AFM.
Note 5: This may be accomplished by inserting copies of
Temporary Revision 16 in the AFM. When these temporary revisions
have been incorporated into general revisions of the AFM, the
general revisions may be inserted in the AFM, provided the
[[Page 53888]]
information contained in the general revisions is identical to that
specified in Temporary Revision 16.
(4) Establish an FAA-approved system to provide forecasts and
reports of freezing rain and freezing drizzle at enroute altitudes
along the route of flight and at all airports considered in the
flight planning process. Training concerning the use of these icing
forecasts and reports shall be accomplished at intervals not to
exceed one year in accordance with Flight Standards Information
Bulletin ``ATR-42 and ATR-72 Airworthiness Directive T95-02-51
Compliance Procedures,'' dated January 11, 1995.
Note 6: Training conducted previously in compliance with the
requirements of AD 95-02-51, amendment 39-9152, may serve as initial
training for purposes of computing the training interval.
(5) Prior to flight in known or forecast icing conditions, and
thereafter at intervals not to exceed one year, conduct flight crew
training based on the revised ATR Icing Procedures Brochure
``Freezing Drizzle: Towards a Better Knowledge and a Better
Protection,'' Issue 1, dated May 11, 1995.
Note 7: Training conducted previously in compliance with the
requirements of AD 95-02-51, amendment 39-9152, may serve as initial
training for purposes of computing the training interval.
(d) 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, Standardization Branch, ANM-113,
FAA, Transport Airplane Directorate. Operators shall submit their
requests through an appropriate FAA Principal Operations Inspector,
who may add comments and then send it to the Manager,
Standardization Branch, ANM-113.
Note 8: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(e) 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 October 12, 1995.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-25836 Filed 10-17-95; 8:45 am]
BILLING CODE 4910-13-U
