Airworthiness Directives; De Havilland Model DHC-8-100 and DHC-8- 300 Series Airplanes

[Federal Register Volume 60, Number 12 (Thursday, January 19, 1995)]
[Rules and Regulations]
[Pages 3737-3739]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-1127]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-235-AD; Amendment 39-9122; AD 94-22-10 R1]


Airworthiness Directives; De Havilland Model DHC-8-100 and DHC-8-
300 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment revises an existing airworthiness directive 
(AD), applicable to certain De Havilland Model DHC-8-100 and DHC-8-300 
series airplanes, that currently requires a revision to the Airplane 
Flight Manual (AFM) to advise flight crew members that certain cockpit 
indications may reveal faulty anti-collision strobe light units, and to 
provide procedures for subsequent flight crew and maintenance action. 
That AD also requires a modification that eliminates the need for the 
AFM revision. That AD was prompted by reports that the function of the 
proximity switch electronics unit (PSEU) may be adversely affected 
during operation of the white anti-collision lights. The actions 
specified by that AD are intended to ensure correct operation of the 
PSEU and its associated systems. This amendment revises the 
applicability of the existing AD to add one model of affected 
airplanes.

DATES: Effective February 3, 1995.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of December 15, 1994 (59 FR 58765, November 15, 1994).
    Comments for inclusion in the Rules Docket must be received on or 
before March 20, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-235-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
De Havilland, Inc., Garratt Boulevard, Downsview, Ontario M3K 1Y5, 
Canada. This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, 
Engine and Propeller Directorate, New York Aircraft Certification 
Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Michele Maurer, Aerospace Engineer, 
Systems and Equipment Branch, ANE-173, New York Aircraft Certification 
Office, FAA, Engine and Propeller Directorate, 181 South Franklin 
Avenue, Room 202, Valley Stream, New York 11581; telephone (516) 791-
6427; fax (516) 791-9024.

SUPPLEMENTARY INFORMATION: On October 26, 1994, the FAA issued AD 94-
22-10, amendment 39-9060 (59 FR 58765, November 15, 1994), which is 
applicable to certain De Havilland Model DHC-8-100 and -300 series 
airplanes. That action requires a revision to the FAA-approved Airplane 
Flight Manual (AFM) to advise the flight crew that certain cockpit 
indications may reveal faulty anti-collision strobe light units, and to 
provide procedures for subsequent flight crew and maintenance action. 
It also requires the installation of a modification that eliminates the 
need for the AFM revision.
    That action was prompted by reports indicating that the electrical 
power supplies of the white anti-collision lights may develop a fault 
that produces greater than normal electrical emissions. The cause of 
this fault has been attributed to a capacitor failure in some 
``Grimes'' strobe light systems. This electromagnetic interference can 
adversely affect the operation of the proximity switch electronics unit 
(PSEU) and its associated systems. Incorrect operation of the PSEU and 
its associated systems may interfere with or distract the flight crew 
in carrying out its regular duties during flight or on the ground, and 
thus serve to compromise the safe operation of the airplane. The 
requirements of AD 94-22-10 are intended to ensure the correct 
operation of the PSEU and its associated systems.
    The AFM revision that is required by AD 94-22-01 is intended to 
advise the flight crew of the fact that the electrical power supplies 
for the white anti-collision lights may fail and cause various abnormal 
indications, such as:

[[Page 3738]]

    1. flashing of the landing gear green locked down advisory lights 
during cruise;
    2. fluctuation of cabin pressurization rate needle during cruise;
    3. retraction and extension of roll and ground spoilers during 
ground operation;
    4. loss of nose landing gear steering subsequent to landing; and
    5. loss of wheel brakes below 35-40 knots.
    The AFM revision advises the flight crew that, if any of these 
abnormal indications are observed, they must select the ``A/COL light 
switch--RED,'' and leave the switch in this position for the remainder 
of the flight.
    The flight crew and maintenance procedures that are required by AD 
94-22-10 are described in De Havilland Alert Service Bulletin S.B. A8-
33-33, dated May 31, 1993. These procedures are intended to detect 
faulty power supply units. The alert service bulletin also describes 
procedures for replacement of any faulty ``Grimes'' unit with either a 
new or serviceable ``Grimes'' unit or a new ``Whelan'' system 
(Modification 8/1273).
    The terminating modification that is required by AD 94-22-10 is 
described in De Havilland Service Bulletin S/B 8-33-19, ``Revision A'', 
dated May 31, 1993. This modification (Modification 8/1273) entails 
replacing the existing anti-collision strobe light system (consisting 
of anti-collision strobe lights, brackets, and power supplies) at all 
three locations with a new, improved ``Whelan'' anti-collision strobe 
light system. (The ``Whelan'' system includes new dual strobes, new 
brackets, and new power supplies.) This new system is considered more 
durable than the currently installed anti-collision strobe light 
system. The ``Whelan'' system also has a back-up strobe light at each 
position.
    Subsequent to the issuance of AD 94-22-10, the FAA identified a 
typographical error in the applicability of the rule: The applicability 
statement of the AD listed ``de Havilland Model DHC-8-302'' as a series 
of airplanes that is subject to the requirements of the rule; however, 
that model should have been listed as ``de Havilland Model DHC-8-301.'' 
This airplane model is manufactured in Canada and is type certificated 
for operation in the United States under the provisions of Section 
21.29 of the Federal Aviation Regulations and the applicable bilateral 
airworthiness agreement.

    Note: There is no ``Model DHC-8-302'' that is currently type 
certificated.

    The FAA has determined that the unsafe condition addressed by AD 
94-22-10 is likely to exist or develop in Model DHC-8-301 series 
airplanes. Therefore, AD 94-22-10 must be revised to correctly add 
these airplanes to its applicability, thereby making them subject to 
its requirements.
    There currently are no Model DHC-8-301 series airplanes on the U.S. 
Register, however. These airplanes are operated currently by non-U.S. 
operators under foreign registry; therefore, they are not directly 
affected by this AD action. However, the FAA considers that this 
revision to the existing AD is necessary to ensure that the unsafe 
condition is addressed in the event that any of these airplanes are 
imported and placed on the U.S. Register in the future.
    Should an affected Model DHC-8-301 series airplane be imported and 
placed on the U.S. Register in the future, it would require 
approximately 16 work hours to accomplish the required actions, at an 
average labor charge of $60 per work hour. Required parts for 
installation of Modification 8/1273 at all three locations would cost 
approximately $1,397 per airplane. Based on these figures, the total 
cost impact of this AD on an operator of a Model DHC-8-301 series 
airplane would be $2,357 per airplane.

(The current requirements of AD 94-24-01 affect approximately 74 
airplanes of U.S. registry. Accomplishment of the currently required 
actions take approximately 16 work hours per airplane, at an average 
labor rate of $60 per airplane. Required parts for installation of 
Modification 8/1273 at all three locations cost approximately $1,397 
per airplane. Based on these figures, the total cost impact of the 
current requirements of this rule on U.S. operators is estimated to be 
$174,418, or $2,357 per airplane.)
    Since this revision action does not affect any airplane that is 
currently on the U.S. register, it has no adverse economic impact and 
imposes no additional burden on any person. Therefore, notice and 
public procedures hereon are unnecessary and the amendment may be made 
effective in less than 30 days after publication in the Federal 
Register.

Comments Invited

    Although this action is in the form of a final rule and was not 
preceded by notice and opportunity for public comment, comments are 
invited on this rule. Interested persons are invited to comment on this 
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 under the caption 
ADDRESSES. All communications received on or before the closing date 
for comments will be considered, and this rule may be amended in light 
of the comments received. Factual information that supports the 
commenter's ideas and suggestions is extremely helpful in evaluating 
the effectiveness of the AD action and determining whether additional 
rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-235-AD.'' The postcard will be date stamped and 
returned to the commenter.
    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, Incorporation by 
reference, Safety. 

[[Page 3739]]


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. 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 removing amendment 39-9060 (59 FR 
58765, November 15, 1994), and by adding a new airworthiness directive 
(AD), amendment 39-9122, to read as follows:

94-22-10 R1  De Havilland: Amendment 39-9122. Docket 94-NM-235-AD. 
Revises AD 94-22-10, Amendment 39-9060.

Applicability: Model DHC-8-102, -103, -301, and -311 series 
airplanes, having serial numbers 003 through 214, inclusive; on 
which Modification 8/1273 (as described in De Havilland Service 
Bulletin S/B No. 8-33-19, Revision `A', dated May 31, 1993) has not 
been accomplished; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure correct operation of the proximity switch electronics 
unit (PSEU) and its associated systems, accomplish the following:
    (a) Within the applicable time specified in paragraph (a)(1) or 
(a)(2) of this AD, revise the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) to include the following 
statement. The revision of the AFM may be accomplished by inserting 
a copy of this AD into the AFM.
    ``The electrical power supplies for the white anti-collision 
lights may fail and cause the following abnormalities:

--Flashing of the landing gear green locked down advisory lights 
during cruise;
--Fluctuation of cabin pressurization rate needle during cruise; and
--Retraction and extension of roll and ground spoilers during ground 
operation.

    The failure may also result in loss of nose landing gear 
steering subsequent to landing, and loss of wheel brakes below 35-40 
knots.
    If any of these abnormal indications are observed, select A/COL 
light switch--RED. Leave the switch in this position for the 
remainder of the flight.''
    (1) For Model DHC-8-102, -103, and -311 series airplanes: 
Accomplish the revision of the AFM within 30 days after December 15, 
1994 (the effective date of AD 94-22-01, amendment 39-9060),
    (2) For Model DHC-8-301 series airplanes: Accomplish the 
revision of the AFM within 30 days after the effective date of this 
amendment.
    (b) If the flight crew reports the occurrence of any of the 
cockpit indications stated in paragraph (a) of this AD: Prior to the 
next flight, perform the maintenance procedures to confirm and 
isolate the faulty power supply unit, in accordance with paragraph 
III., Part B, Accomplishment Instructions of de Havilland Alert 
Service Bulletin S.B. A8-33-33, dated May 31, 1993.
    (1) If any power supply unit is determined to be faulty, prior 
to further flight, replace the unit with a new or serviceable 
``Grimes'' unit or a new ``Whelen'' system in accordance with the 
alert service bulletin.
    (2) If the specific unit causing the faults cannot be 
determined, prior to further flight, replace all three units with 
new or serviceable ``Grimes'' units or a new ``Whelen'' system in 
accordance with the alert service bulletin. Installation of a new 
``Whelen'' system at all three locations constitutes terminating 
action for the requirements of this AD and, following installation, 
the AFM revision required by paragraph (a) of this AD may be 
removed.
    (c) Within 6 months after the effective date of this AD, install 
Modification 8/1273 (which entails replacement of the existing anti-
collision strobe lights, brackets, and power supplies with the 
```Whelen' Anti-Collision Strobe Light System'') at all three 
locations, in accordance with de Havilland Service Bulletin S/B No. 
8-33-19, Revision `A', dated May 31, 1993. Following installation, 
the AFM revision required by paragraph (a) of this AD may be 
removed.
    (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, New York Aircraft Certification 
Office (ACO), ANE-170, FAA, Engine and Propeller Directorate. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, New York ACO.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the New York ACO.

    (e) Special flight permits may be issued in accordance with 
Secs. 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.
    (f) The actions shall be done in accordance with de Havilland 
Alert Service Bulletin S.B. A8-33-33, dated May 31, 1993; and de 
Havilland Service Bulletin S/B No. 8-33-19, Revision `A', dated May 
31, 1993; as applicable. This incorporation by reference was 
approved previously by the Director of the Federal Register, in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51, as of December 
15, 1994 (59 FR 58765, November 15, 1994). Copies may be obtained 
from de Havilland, Inc., Garratt Boulevard, Downsview, Ontario M3K 
1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
FAA, Engine and Propeller Directorate, New York Aircraft 
Certification Office, 181 South Franklin Avenue, Room 202, Valley 
Stream, New York; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on February 3, 1995.

    Issued in Renton, Washington, on January 11, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-1127 Filed 1-18-95; 8:45 am]
BILLING CODE 4910-13-M

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