[Federal Register Volume 65, Number 99 (Monday, May 22, 2000)]
[Rules and Regulations]
[Pages 32011-32013]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-12672]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-138-AD; Amendment 39-11735; AD 2000-10-11]
RIN 2120-AA64


Airworthiness Directives; Gulfstream Model G-159 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Gulfstream Model G-159 series airplanes, that 
requires an inspection to determine the type of pneumatic deicing 
boots, and an Airplane Flight Manual (AFM) revision only for those 
airplanes equipped with ``modern'' boots. This amendment is 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 this 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.

EFFECTIVE DATE: June 26, 2000.

ADDRESSES: Information pertaining to this amendment may be examined at 
the Federal Aviation Administration (FAA), Transport Airplane 
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; 
or at the FAA, Small Airplane Directorate, Atlanta Aircraft 
Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 
450, Atlanta, Georgia 30349.

FOR FURTHER INFORMATION CONTACT: Neil Berryman, Aerospace Engineer, 
Systems and Flight Test Branch, ACE-116A, FAA, Small Airplane 
Directorate, Atlanta Aircraft Certification Office, One Crown Center, 
1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone 
(770) 703-6098; fax (770) 703-6097.

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 Gulfstream Model G-159 series 
airplanes was published as a supplemental notice of proposed rulemaking 
(NPRM) in the Federal Register on November 18, 1999 (64 FR 62991). That 
action proposed to require

[[Page 32012]]

an inspection to determine the type of pneumatic deicing boots, and an 
airplane flight manual (AFM) change only for those airplanes equipped 
with ``modern'' boots.

Since the Issuance of the NPRM

    The FAA has received information indicating that natural ice 
shedding, melting, or sublimation from the protected areas of the 
pneumatic deicing boot system of the wing and tail leading edge will 
eliminate most residual ice. In light of that information, the FAA has 
determined that a revision of the last bulleted paragraph of the 
airplane flight manual revision specified in paragraph (a) of the NPRM 
is necessary. Consequently, that paragraph has been revised from, ``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,'' to delete the phrase, ``and after 
the airplane is determined to be clear of ice.''

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request to Add Further Requirements

    The commenter, the United Kingdom Civil Aviation Authority, 
requests that the statement in the supplemental notice of proposed 
rulemaking (NPRM) advising that a potential for adverse aerodynamic 
effects of ice adhering to the airplane exists should be addressed in 
more detail. The commenter explains that icing boots contaminated with 
dirt or in a deteriorated condition can induce such ice adhering to the 
airplane. The commenter points out that various cleaning and protection 
fluids are available that provide extended life to the deicing boots, 
protection of the boots against ultraviolet (UV) rays, and assistance 
in maintaining the boots in a clean condition. However, the commenter 
notes that not all maintenance programs schedule tasks effectively for 
the use of such cleaning and protection fluids. Therefore, the 
commenter requests that the FAA consider mandating a specific schedule 
to use such cleaning and protection products. The commenter states that 
such a required schedule should be required for airplanes equipped with 
either the ``modern'' or ``older'' boots.
    The FAA does not concur with the commenter's requests. The FAA 
considers that normal wear and tear on the deicing boot materials is to 
be expected, and that the adhesion characteristics of the boot 
increases as the boot surface degrades over time. Operators have the 
responsibility to monitor the performance of the deicing boots 
installed on their airplanes, and to perform maintenance as required.
    The FAA acknowledges that use of certain ice-phobic chemicals may 
provide an additional safety benefit. However, a variety of factors 
(e.g., normal wear and tear, ``patching,'' and oxidation of boot 
material) exist in varying degrees on individual airplanes. As a 
result, the optimum frequency of application will vary during the life 
of the boot. The FAA has received no quantitative data to demonstrate 
the adequacy of particular amounts of ice-phobic chemical sprays or to 
provide adequate intervals of application. Therefore, the FAA cannot 
establish an appropriate application interval at this time. However, if 
additional data becomes available, the FAA may consider further 
rulemaking.

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

    The FAA estimates that 141 airplanes of U.S. registry will be 
affected by this AD.
    The FAA estimates that it will take approximately 2 work hours per 
airplane to accomplish the AFM revision, at the average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the AD on 
U.S. operators is estimated to be $16,920, or $120 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.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    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.


Sec. 39.13  [Amended]

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

2000-10-11 Gulfstream Aerospace Corporation  (Formerly Grumman): 
Amendment 39-11735. Docket 99-NM-138-AD.

    Applicability: Model G-159 series airplanes equipped with 
pneumatic deicing boots, certificated in any category.
    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.)


[[Page 32013]]


    (a) Within 10 days after the effective date of this AD: Perform 
a visual inspection to determine if the types of pneumatic deicing 
boots installed are 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.
    ``<bullet> 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.
    ``<bullet> 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.
    <bullet> The wing and tail leading edge pneumatic deicing boot 
system may be deactivated only after leaving icing conditions.''

    (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, Atlanta Aircraft Certification 
Office, FAA, Small Airplane Directorate. The request shall be 
forwarded through an appropriate FAA Operations Inspector, who may 
add comments and then send it to the Manager, Atlanta ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta 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 June 26, 2000.

    Issued in Renton, Washington, on May 15, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-12672 Filed 5-19-00; 8:45 am]
BILLING CODE 4910-13-U