[Federal Register Volume 60, Number 116 (Friday, June 16, 1995)]
[Proposed Rules]
[Pages 31647-31649]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-14766]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-19-AD]
Airworthiness Directives; General Dynamics (Convair) Model 240
Series Airplanes, Including Model T-29 (Military) Airplanes; Model 340
and 440 Series Airplanes; and Model C-131 (Military) Airplanes;
Including Those Modified for Turbo-Propeller Power
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to various General Dynamics (Convair)
airplanes. This proposal would require revising the Airplane Flight
Manual to require that the flight crew limit the flap settings during
certain icing conditions and air temperatures. This proposal is
prompted by reports indicating that incidents involving uncommanded
pitch excursions have occurred due to ice contaminated tailplane stall
(ICTS) that occurred during or following flight in icing conditions. If
flap settings are increased for landing when ICTS is present, elevator
control could be affected adversely and the airplane could descend
uncontrollably. The actions specified by the proposed AD are intended
to ensure that the flight crew is advised of the potential hazard
related to increasing the flap settings when ICTS is present, and the
procedures necessary to address it.
DATES: Comments must be received by August 14, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-19-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9 a.m. and 3 p.m., Monday through Friday, except Federal
holidays.
FOR FURTHER INFORMATION CONTACT: Andrew Gfrerer, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount
Boulevard, Lakewood, California 90712; telephone (310) 627-5338; fax
(310) 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 95-NM-19-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-19-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports indicating that incidents involving
uncommanded pitch excursions have occurred on various turbo-propeller
powered airplanes, including General Dynamics (Convair) airplanes.
These pitch excursions were caused by ice contaminated tailplane stall
(ICTS), which occurred during or following flight in icing conditions.
If the flap settings are increased for landing when ICTS is present,
elevator control could be affected adversely. This condition, if not
corrected, could result in uncontrollable descent of the airplane.
Icing conditions can be encountered during the approach for the
landing phase of flight. Further, ice can accumulate on the tailplane
before it begins to accumulate on the wings. Since ice may form
quickly, in the case of the tailplane, such ice formation could reach
hazardous proportions during the approach phase without any prior
evidence of its presence in the ``clean'' (cruise) configuration.
The flight crew can only determine if ice is forming on the
airplane by looking out the window at the wings. If the flight crew
does not observe any ice on the wings, they could assume that the
airplane is free of ice and proceed to select certain flap settings
during the approach phase without properly configuring the airplane for
icing conditions by turning on the anti-icing system. In addition, the
flight crew may increase the flap settings for landing and,
consequently, elevator control can be affected adversely.
In response to the reports of uncommanded pitch excursions, the FAA
and the National Aeronautics and Space Administration (NASA) sponsored
two International Tailplane Icing workshops in November 1991 and April
1993. In addition to representatives from the FAA and NASA, workshop
participants included representatives from certain foreign
airworthiness authorities, foreign and domestic manufacturers, and
industry. As a result of these workshops, emphasis was placed on
improving flight crew awareness of ICTS. For the longer term, a review
of certain Federal Aviation Regulations (FAR) that pertain to ice
protection/detection and tailplane aerodynamic issues also was
conducted.
Additionally, the FAA conducted flight tests on various turbo-
propeller powered airplanes, including General Dynamics (Convair) Model
5800 series airplanes. (This airplane model is similar to a Model 340
series airplane equipped with turbo-prop engines.) During the
certification of Model 5800 series airplanes, the FAA performed a
series of flight test maneuvers to determine if the airplane would be
susceptible to ICTS. Results of these flight test maneuvers indicate
that these airplanes are susceptible to ICTS. Such susceptibility is
directly related to the angle-of-attack (AOA) of the tailplane and the
sensitivity of the airfoil to degradation by contamination often
associated with efficient airfoil design.
The FAA has issued a number of airworthiness directives (AD) to
correct the same unsafe condition described previously on various
transport category airplane types. Examples of those AD's include the
following:
--AD 86-20-02, amendment 39-5429 (51 FR 34452, September 29, 1986),
applicable to Aerospatiale Model ATR-42 series airplanes;
--AD 91-16-01, amendment 39-7091 (56 FR 37468, August 7, 1991),
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applicable to Mitsubishi Heavy Industries (MHI) Model YS-11 and -11A
series airplanes; and
--AD 86-06-03 R1, amendment 39-5917 (53 FR 16385, May 9, 1988),
applicable to SAAB-Fairchild Model SF-340A series airplanes.
The FAA finds that the FAA-approved Airplane Flight Manual (AFM)
for General Dynamics (Convair) Model 240 series airplanes [including
Model T-29 (military) airplanes], Model 340 and 440 series airplanes,
and Model C-131 (military) airplanes, including those modified for
turbo-propeller power, must be revised. This revision must include
procedures to ensure that the flight crew does not select a flap
setting of more than 30 degrees after icing conditions have been
encountered, when icing conditions are anticipated during approach and
landing, or when the outside air temperature is +5 degrees Celsius or
below and any visible moisture is present. The FAA has determined that
such procedures currently are not defined adequately in the AFM for
these airplanes.
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require revising the Limitations Section of the FAA-
approved AFM to limit flap selection during certain icing conditions
and air temperatures.
There are approximately 282 Model 240 series airplanes, including
Model T-29 (military) airplanes; Model 340 and 440 series airplanes;
Model C-131 (military) airplanes, and those models modified for turbo-
propeller power; of the affected design in the worldwide fleet. The FAA
estimates that 197 airplanes of U.S. registry would be affected by this
proposed AD, that it would take approximately 1 work hour per airplane
to accomplish the proposed actions, and that the average labor rate is
$60 per work hour. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $11,820, or $60 per
airplane.
The total 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.
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 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 adding the following new
airworthiness directive:
General Dynamics (Convair): Docket 95-NM-19-AD.
Applicability: All Model 240 series airplanes, including Model
T-29 (military) airplanes; Model 340 and 440 series airplanes; and
Model C-131 (military) airplanes; including those models modified
for turbo-propeller power (commonly referred to as Model 580, 600,
and 640 series airplanes); certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure that the flight crew is advised of the potential
hazard associated with increasing the flap settings when ice
contaminated tailplane stall (ICTS) is present, and the procedures
necessary to address it, accomplish the following:
(a) Within 30 days after the effective date of this AD, revise
the Limitations Section of the FAA-approved Airplane Flight Manual
(AFM) to include the following procedures, which will limit the flap
settings during certain icing conditions and air temperatures. This
may be accomplished by inserting a copy of this AD in the AFM.
``Flap Limitation in Icing Conditions
Flap selection is limited to a maximum of 30 degrees after icing
conditions have been encountered; or when icing conditions are
anticipated during approach and landing; or when the outside air
temperature is +5 degrees Celsius or below and any visible moisture
is present.''
(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. 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.
(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 June 12, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-14766 Filed 6-15-95; 8:45 am]
BILLING CODE 4910-13-U