[Federal Register Volume 65, Number 3 (Wednesday, January 5, 2000)]
[Proposed Rules]
[Pages 399-400]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-136]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-261-AD]
RIN 2120-AA64


Airworthiness Directives; Construcciones Aeronauticas, S.A. 
(CASA) Model CN-235-100 and CN-235-200 Series Airplanes

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 all CASA Model CN-235-100 and CN-
235-200 series airplanes. This proposal would require replacement of 
existing anti-icing distributor valves with new, improved valves. This 
proposal is prompted by issuance of mandatory continuing airworthiness 
information by a foreign civil airworthiness authority. The actions 
specified by the proposed AD are intended to prevent ice accumulation 
on the wings or tail of the airplane, which could result in reduced 
controllability of the airplane.

DATES: Comments must be received by February 4, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-261-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.
    The service information referenced in the proposed rule may be 
obtained from Construcciones Aeronauticas, S.A., Getafe, Madrid, Spain. 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 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 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-261-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-261-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On December 26, 1989, a British Aerospace Jetstream Model BA-3101 
series airplane impacted the ground approximately 400 feet short of the 
runway while executing an instrument landing system (ILS) approach. The 
accident occurred at the Tri-Cities Airport, Pasco, Washington. The 
National Transportation Safety Board (NTSB) determined that the 
probable cause of the accident was the flightcrew's decision to 
continue an unstabilized ILS approach that led to a stall, most likely 
of the horizontal stabilizer, and loss of control at low altitude. 
Contributing to the stall and loss of control was the accumulation of 
leading edge ice, which degraded the aerodynamic performance of the 
airplane.
    One result of the NTSB investigation was the determination that the 
flight deck wing de-icing light illuminated at a lower pressure than 
the pressure required to fully inflate the de-icing boots. The 
premature illumination of the wing de-icing light was due to a failure 
within the wing de-icing boot system, which allowed sufficient air 
pressure to give the appearance of normal operation based on the de-
icing light, without actually inflating the boots sufficiently to 
remove ice.
    Based on an NTSB Safety Recommendation, the FAA reviewed the 
pneumatic de-icing boot system designs for airplanes operated under 
parts 121 and 135 of the Federal Aviation Regulations to ensure that 
the pneumatic pressure threshold at which each de-icing boot indication 
light is designed to illuminate is sufficient pressure for effective 
operation of the pneumatic de-icing boots. The FAA has determined that 
the existing design of the flight deck pneumatic de-icing boot pressure 
indicator switch on CASA Model CN-235-100 and CN-235-200 series 
airplanes may allow the flight deck indicator light to illuminate at a 
lower pressure than the pressure required to fully inflate the de-icing 
boots [15 pounds per square inch gage (psig)]. Illumination of the 
light at a lower pressure would indicate to the flightcrew that the 
pneumatic ice boots are operating normally, though the boots may not be 
sufficiently inflated to shed ice. This condition, if not corrected, 
could result in ice accumulation on the wings or tail of the airplane, 
which could result in reduced controllability of the airplane.

[[Page 400]]

Explanation of Relevant Service Information

    CASA has issued Service Bulletin SB-235-30-14, dated August 13, 
1999, which describes procedures for replacement of existing anti-icing 
distributor valves in the wing and tail areas of the airplane with new, 
improved valves. The new, improved valves increase the weak pressure of 
the anti-icing distributor valves pressure sensor to 15.5 psig 
(<plus-minus>0/5 psig). Accomplishment of the actions specified in the 
service bulletin is intended to adequately address the identified 
unsafe condition. The Direccion General de Aviacion Civil (DGAC), which 
is the airworthiness authority for Spain, classified this service 
bulletin as mandatory and issued Spanish airworthiness directive 04/99, 
dated July 30, 1999, in order to assure the continued airworthiness of 
these airplanes in Spain.

FAA's Conclusions

    These airplane models are manufactured in Spain 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. Pursuant to this 
bilateral airworthiness agreement, the DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, reviewed all available information, and determined that AD 
action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    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 proposed AD would require accomplishment of 
the actions specified in the service bulletin described previously.

Cost Impact

    The FAA estimates that 2 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 30 work 
hours per airplane to accomplish the proposed replacement, and that the 
average labor rate is $60 per work hour. Required parts would cost 
approximately $4,671 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $12,942, 
or $6,471 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 a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Construcciones Aeronauticas, S.A. (CASA): Docket 99-NM-261-AD.

    Applicability: All Model CN-235-100 and CN-235-200 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 (c) 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 prevent ice accumulation on the wings or tail of the 
airplane, which could result in reduced controllability of the 
airplane, accomplish the following:

Replacement

    (a) Within 4 months after the effective date of this AD, replace 
the existing anti-icing distributor valves, having part number (P/N) 
AC960013, in the wing and tail areas of the airplane, with new, 
improved valves, having P/N AC911016, in accordance with CASA 
Service Bulletin SB-235-30-14, dated August 13, 1999.
    (b) As of the effective date of this AD, no person shall install 
a distributor valve having P/N AC960013 on any airplane.

Alternative Methods of Compliance

    (c) 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, International Branch, ANM-116, 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, International 
Branch, ANM-116.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

Special Flight Permits

    (d) 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.

    Note 3: The subject of this AD is addressed in Spanish 
airworthiness directive 04/99, dated July 30, 1999.

    Issued in Renton, Washington, on December 29, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-136 Filed 1-4-00; 8:45 am]
BILLING CODE 4910-13-U