[Federal Register Volume 59, Number 93 (Monday, May 16, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8177]
[[Page Unknown]]
[Federal Register: May 16, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-98-AD; Amendment 39-8872; AD 94-08-01]
Airworthiness Directives; British Aerospace Model ATP Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to all British Aerospace Model ATP airplanes, that requires
revising the Airplane Flight Manual (AFM) to prohibit flight in certain
freezing precipitation conditions. This AD also provides an optional
terminating action for the AFM revision. This amendment is prompted by
reports of engine power rollback (loss of engine power) that occurred
in environmental conditions involving freezing precipitation. The
actions specified by this AD are intended to prevent loss of multiple
engine power during flight in freezing precipitation.
DATES: Effective June 15, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 15, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Jetstream Aircraft, Inc., P.O. Box
16029, Dulles International Airport, Washington, DC 20041-6029. This
information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue,
SW., Renton, Washington; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2148; fax (206) 227-1320.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to all British Aerospace Model ATP airplanes was published
in the Federal Register on September 3, 1993 (58 FR 46916). That action
proposed to require revising the Airplane Flight Manual (AFM) to
prohibit flight in certain freezing precipitation conditions.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule, but suggests that the
action should have been issued to require immediate compliance to
reduce the traveling public's exposure to the potential risk of loss of
multiple engine power during flight in freezing precipitation and
possible unplanned landings. The commenter also requests that, since
the AD was issued as a proposal, the time required for publication of
the final rule in the Federal Register be kept to a minimum so as not
to induce an additional administrative delay that would only delay
compliance.
The FAA does not concur with the commenter's suggestion that the
final rule be issued to require immediate compliance. At the time of
issuance of the proposal, the FAA could not justify that an immediate
safety of flight problem existed, especially in light of the fact that
the single operator of the entire U.S. fleet of Model ATP airplanes
already had added an operating restriction similar to that required by
this AD to its FAA-approved operation specifications and had agreed to
operate in accordance with that restriction until further corrective
action could be identified and incorporated. Moreover, the operating
limitation was proposed by the FAA since, at that time, the airplane
manufacturer, the Civil Aviation Authority (CAA), which is the
airworthiness authority for the United Kingdom, and the FAA were
uncertain as to the cause of the engine power rollback problem
described in the preamble to the proposal. However, considerable
information was available at that time to indicate that the problem was
due to ice ingestion into the engines during certain meteorological
conditions. That data, however, had not yet been confirmed through
testing conducted by the manufacturer and the CAA. Consequently, the
FAA determined that a requirement to prohibit flight in certain
freezing precipitation conditions would provide an acceptable level of
safety until terminating action could be identified and developed.
In developing this AD action, the FAA considered all of these
items, and determined that, since the continued operational safety of
the U.S. fleet could be assured during the interim, it was not
impracticable to provide notice and the opportunity for public comment
on the proposed rule.
Two commenters, the CAA and Jetstream, request that the proposed
rule be revised to require establishing a life limit on the engine
igniter plugs, installing a bypass duct outlet eductor, and
incorporating other changes to the airplane flight manual (AFM), in
lieu of the proposed AFM revision. The commenters contend that, if such
interim measures are taken, an acceptable level of safety would be
assured pending longer term corrective action. The commenters explain
that service information has been issued that describes procedures for
those actions, as follows:
1. Jetstream Service Bulletin ATP-80-06, Revision 1, dated October
22, 1993, which describes procedures for placing a life limit on the
engine igniter plugs and replacing those parts at staggered periods in
order to improve ignition reliability.
2. Jetstream Service Bulletin ATP-54-12-35274A, Revision 1, dated
December 15, 1993, which describes procedures for installation of an
eductor plate over the exhaust port of the engine air intake system.
Accomplishment of this installation will increase the air flow rate
down the exhaust port.
3. Temporary Revision No. T/33, Issue 1, dated November 1, 1993,
which revises AFM Document No. ATP 004. This temporary revision
describes revisions to the Limitations and Normal Procedures sections
of the FAA-approved AFM to introduce procedures for operation in icing
conditions. The changes include a ground inspection of the engine inlet
prior to flight, staggered selection of the left- and right-hand engine
de-ice systems to ensure that the likelihood of simultaneous engine
rundown on final approach is minimized, and a small increase in the
final approach speed to ensure safe landing.
Jetstream also suggests two other alternatives that would provide
an adequate level of safety, wherein the proposed AFM limitation could
be removed:
1. Modification of the engine inlets, in addition to accomplishment
of the interim measures discussed previously (a life limit on the
engine igniter plugs, installation of a bypass duct outlet eductor, and
certain changes to the AFM). Jetstream indicates that these modified
engine inlets demonstrate a significant improvement in de-icing
effectiveness in the range of temperatures and airplane speeds in which
power rollbacks have been experienced.
Jetstream service bulletins that relate to the engine inlet
modification are described as follows: Jetstream Service Bulletin ATP-
54-13-35274B, dated October 9, 1993, describes procedures for
installing engine air inlet ducts that incorporate electrical de-ice
heaters with increased power and area. The service bulletin also
describes procedures for performing associated electrical system
changes. The installation involves installing engine air inlet ducts
that incorporate an enlarged heater mat with revised electrical power
densities adjacent to the engine intake flange. Jetstream Service
Bulletin ATP-54-14, dated October 14, 1993, describes procedures for
repetitive visual inspections of the heater mats for damage, and
replacement of the engine air intake, if necessary.
2. Accomplishment of special operating procedures, not specifically
defined by the commenter. Jetstream considers that requiring such
operating procedures is a proven and acceptable means of providing an
adequate level of safety, as generally demonstrated by the operation of
aircraft throughout their flight spectra, in accordance with AFM's.
Jetstream submits one final suggestion in the event the FAA
proceeds with requiring the proposed operating limitation. In this
case, the commenter suggests that the actions described in Jetstream
Service Bulletins ATP-54-13-35274B and ATP-54-14, in addition to the
interim measures discussed previously (a life limit on the engine
igniter plugs, installation of a bypass duct outlet eductor, and
certain changes to the AFM), be accomplished as an alternative method
of compliance for the proposed operating limitation.
The FAA concurs partially. The interim measures proposed by the CAA
and Jetstream were based, to a large extent, on the flight crew
performing special operating procedures to ensure a safe landing after
one or both engines had run down due to ice ingestion. However, the FAA
considers that requiring the flight crew to perform such special
operating procedures over a long term period may not provide the degree
of safety assurance necessary for these airplanes. The FAA has
determined that requiring the proposed operating limitation to prohibit
flight into certain meteorological conditions known to cause engine
rundown will provide an acceptable level of safety until additional
hardware modifications can be identified and installed on these
airplanes.
However, the FAA concurs with Jetstream's suggestion that the
accomplishment of the interim measures and modification of the engine
inlets may be accomplished as optional terminating action for the
operating limitation. Since the issuance of the proposed rule,
Jetstream has issued Temporary Revision No. T/38, Issue 1, dated
February 16, 1994, which revises certain pages of Temporary Revision
No. T/33 (discussed previously). Temporary Revision No. T/38 amends the
Normal Procedures section of the AFM as related to operation of engine
continuous ignition during flight in icing conditions. The FAA finds
that this new information must be included in the AFM for Model ATP
airplanes in order to assure continued reliability and to prevent
unnecessary wear on engine ignition systems.
Accordingly, the final rule has been revised to include a new
paragraph (b), which includes the following optional terminating
action:
1. Revising the Limitations section and the Normal and Abnormal
Procedures sections of the FAA-approved AFM, to include the information
specified in Temporary Revision No. T/33, Issue 1, dated November 1,
1993, and Temporary Revision No. T/38, Issue 1, dated February 16,
1994, to introduce procedures for operation in icing conditions.
2. Revising the FAA-approved maintenance program to place a life
limit on the engine igniter plugs and to replace those parts at
specified intervals in accordance with Jetstream Service Bulletin ATP-
80-06, Revision 1, dated October 22, 1993.
3. Installing an eductor plate over the exhaust port of the engine
air intake system in accordance with Jetstream Service Bulletin ATP-54-
12-35274A, Revision 1, dated December 15, 1993.
4. Installing engine air inlet ducts that incorporate electrical
de-ice heaters with increased power and area, and performing associated
electrical system changes, in accordance with Jetstream Service
Bulletin ATP-54-13-35274B, dated October 9, 1993.
5. Revising the FAA-approved maintenance program to include
repetitive visual inspections of the heater mats for damage; and, if
any damage is found, replacement of the engine air intake; in
accordance with Jetstream Service Bulletin ATP-54-14, dated October 14,
1993. -
This is considered to be interim action until final action is
identified, at which time the FAA may consider further rulemaking.
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 with the changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
The FAA estimates that 9 airplanes of U.S. registry will be
affected by this AD, that it will take approximately 1 work hour per
airplane to accomplish the required AFM revision, and that the average
labor rate is $55 per work hour. The cost for required parts is
expected to be negligible. Based on these figures, the total cost
impact of the AD on U.S. operators is estimated to be $495, or $55 per
airplane. This total cost figure assumes that no operator has yet
accomplished the requirements of this AD.
Should an operator elect to accomplish the optional terminating
action that is provided by this AD action, the number of work hours
required to accomplish it is approximately 159 per airplane, at an
average labor rate of $55 per work hour. Required modification parts
would be supplied by Jetstream at no cost to operators. Based on these
figures, the total cost impact of the AD for accomplishment of the
optional terminating action is $8,745 per airplane.
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.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations 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:
94-08-01 British Aerospace (Commercial Aircraft), Limited:
Amendment 39-8872. Docket 93-NM-98-AD.
Applicability: All Model ATP airplanes, certificated in any
category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent loss of multiple engine power during flight in
freezing precipitation, 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 statement. This may be accomplished
by inserting a copy of this AD in the AFM.
``Flight is prohibited into forecast or reported freezing
precipitation conditions where the outside air temperature is
between +5 deg.C and -5 deg.C.''
(b) Accomplishment of the actions specified in paragraphs
(b)(1), (b)(2), (b)(3), (b)(4), and (b)(5) constitutes terminating
action for the AFM revision required by paragraph (a) of this AD.
(1) Revise the Limitations section and the Normal Procedures
section of the FAA-approved AFM, to include the information
specified in Temporary Revision No. T/33, Issue 1, dated November 1,
1993, and Temporary Revision No. T/38, Issue 1, dated February 16,
1994, which introduce procedures for operation in icing conditions,
as specified in the temporary revision; and operate the airplane in
accordance with those limitations and procedures.
Note 1: This may be accomplished by inserting copies of
Temporary Revision No. T/33 and No. T/38 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 No. T/33 and No. T/38.
(2) Incorporate a revision into the FAA-approved maintenance
program that provides for replacement of engine igniter plugs at the
intervals specified in Jetstream Service Bulletin ATP-80-06,
Revision 1, dated October 22, 1993. Initial replacement of an engine
igniter plug with a new plug shall be accomplished prior to the
accumulation of 200 total hours time-in-service on the engine
igniter plug, or within 50 hours time-in-service after incorporating
the maintenance program revision, whichever occurs later. -
(3) Install an eductor plate over the exhaust port of the engine
air intake system in accordance with Jetstream Service Bulletin ATP-
54-12-35274A, dated September 28, 1993, or Revision 1, dated
December 15, 1993. Any eductor plate installed in accordance with
the original issue of the service bulletin must be inspected for any
aperture profile mismatch, in accordance with paragraph 2., Part B.,
of the Accomplishment Instructions of Revision 1 of the service
bulletin. If any mismatch is found that exceeds the limit specified
in that service bulletin, prior to further flight, the discrepancy
must be corrected in accordance with paragraph 2., Part C, of
Revision 1 of the service bulletin.
(4) Install engine air inlet ducts that incorporate electrical
de-ice heaters with increased power and area, and perform associated
electrical system changes, in accordance with Jetstream Service
Bulletin ATP-54-13-35274B, dated October 9, 1993.
(5) Revise the FAA-approved maintenance program to include
repetitive visual inspections of the heater mats for damage at
intervals not to exceed 50 hours time-in-service, in accordance with
Jetstream Service Bulletin ATP-54-14, dated October 14, 1993; and,
if any damage is found, prior to further flight, replace the engine
air intake, in accordance with the service bulletin.
(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, Standardization Branch, ANM-113,
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,
Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(d) Special flight permits may be issued in accordance with
Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the
airplane to a location where the requirements of this AD can be
accomplished.
(e) The actions shall be done in accordance with the following
documents, as applicable, which contain the specified effective
pages:
------------------------------------------------------------------------
Service bulletin
referenced and Page No. Revision level shown Date shown on page
date----- on page-
------------------------------------------------------------------------
Temporary Revision 1-5 1.................... November 1, 1993.
No. T/33; Issue
1, November 1,
1993.
Temporary Revision 1-2, 7-8 1.................... February 16, 1994.
No. T/38; Issue 3-4 (These pages are
1, February 16, 5-6 removed). March 5, 1993.
1994. Original
ATP 80-06; 1-3 1.................... October 22, 1993.
Revision 1,
October 22, 1993.
ATP-54-13-35274B, 1-44- Original............. October 9, 1993.
October 9, 1993.
ATP-54-14, October 1-5 Original............. October 14, 1993.
14, 1993.
ATP-54-12-35274A, 1-3, 5, 7 Original............. September 28,
September 28, 4, 6 (These pages are not 1993.
1993. used)
ATP-54-12-35274A; 1-5, 7, 9 1.................... December 15, 1993.
Revision 1, 6, 8 (These pages are not
December 15, 1993. used)
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This incorporation by reference was approved by the Director of
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies may be obtained from Jetstream Aircraft, Inc., P.O.
Box 16029, Dulles International Airport, Washington, DC 20041-6029.
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(f) This amendment becomes effective on June 15, 1994.
Issued in Renton, Washington, on March 31, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-8177 Filed 5-13-94; 8:45 am]
BILLING CODE 4910-13-U
