[Federal Register Volume 64, Number 11 (Tuesday, January 19, 1999)]
[Rules and Regulations]
[Pages 2821-2823]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-1064]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-SW-13-AD; Amendment 39-11002; AD 98-26-06]
Airworthiness Directives; Schweizer Aircraft Corporation Model
269D Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This document publishes in the Federal Register an amendment
adopting Airworthiness Directive (AD) 98-26-06 which was sent
previously to all known U.S. owners and operators of Schweizer Aircraft
Corporation (Schweizer) Model 269D helicopters by individual letters.
This AD requires removing the main rotor drive shaft (shaft) and
inspecting it for cracks. If a crack is found, replacing the shaft with
an airworthy shaft is required. This AD also requires periodically
verifying the torque of the main rotor hub (hub) bolts. This amendment
is prompted by four reports of cracking in the shaft of helicopters
with a large diameter hub. Wear patterns indicate cracking was caused
by loss of clamping torque on the hub and shaft assembly due to the use
of grease between the hub and shaft. This condition, if not corrected,
could result in failure of the shaft and subsequent loss of control of
the helicopter.
DATES: Effective February 3, 1999, to all persons except those persons
to whom it was made immediately effective by Priority Letter AD 98-26-
06, issued on December 9, 1998, which contained the requirements of
this amendment.
Comments for inclusion in the Rules Docket must be received on or
before March 22, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 98-SW-13-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
FOR FURTHER INFORMATION CONTACT: Raymond H. Reinhardt, Aerospace
Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York
Aircraft Certification Office, 10 Fifth St., Valley Stream, NY,
telephone (516) 256-7532, fax (516) 568-2716.
SUPPLEMENTARY INFORMATION: On December 9, 1998, the FAA issued Priority
Letter AD 98-26-06, applicable to Schweizer Model 269D helicopters,
which requires removing the shaft and inspecting it for cracks. If a
crack is found, replacing the shaft with an airworthy shaft is
required. That AD also requires periodically verifying the torque of
the hub bolts. That action was prompted by four reports of cracking in
the shaft of helicopters with a large diameter hub. Wear patterns
indicate cracking was caused by loss of clamping torque on the hub and
shaft assembly due to the use of grease between the hub and shaft. A
pilot reported excessive vibration in one incident. An inspection
following that incident revealed a 2.5-inch horizontal crack in the
shaft. The crack started from one of the three lower bolt holes,
propagated to an adjacent bolt hole, and then propagated from the
second bolt hole in a downward direction. This condition, if not
corrected, could result in failure of the shaft and subsequent loss of
control of the helicopter.
Since the unsafe condition described is likely to exist or develop
on other Schweizer Model 269D helicopters of the same type design, the
FAA issued Priority Letter AD 98-26-06 to prevent failure of the shaft
and subsequent loss of control of the helicopter. The AD requires,
prior to 200 hours time-in-service (TIS), and thereafter at intervals
not to exceed 100 hours TIS, inspecting the shaft for cracks in the
area of the six hub attach bolts using a 10-power or higher magnifying
glass and bright light. If no crack is found as a result of the visual
inspection, the AD requires inspecting the shaft using a magnetic
particle inspection method. If a crack is found, the AD requires
replacing the shaft with an airworthy shaft. The AD also requires
periodically verifying the torque of the hub bolts. The short
compliance time involved is required because the previously described
critical unsafe condition can adversely affect the controllability of
the helicopter. Therefore, the inspections and replacement, if
necessary, are required prior to further flight, and this AD must be
issued immediately.
Since it was found that immediate corrective action was required,
notice and opportunity for prior public comment thereon were
impracticable and contrary to the public interest, and good cause
existed to make the AD effective immediately by individual letters
issued on December 9, 1998, to all known U.S. owners and operators of
Schweizer Model 269D helicopters. These conditions still exist, and the
AD is hereby published in the Federal Register as an amendment to
section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to
make it effective to all persons.
The FAA estimates that 6 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours for
the periodic inspections and 22 work hours to replace the shaft, if
necessary, per helicopter, and the average labor rate is $60 per work
hour. Required parts will cost approximately $12,000 per replacement
shaft. Based on these figures, the total cost impact of the AD on U.S.
operators is estimated to be $80,640 to replace the shafts in all the
helicopters, and $7,200 a year for 10 inspections per year on each
helicopter.
[[Page 2822]]
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an 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 should 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 No. 98-SW-13-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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, 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 a new airworthiness directive
to read as follows:
98-26-06 Schweizer Aircraft Corporation: Amendment 39-11002. Docket
No. 98-SW-13-AD.
Applicability: Model 269D helicopters with a large diameter main
rotor hub (hub), part number (P/N) 269A1002-11, and main rotor drive
shaft (shaft), P/N 269A5305-139, -143, -145, or -147, installed,
certificated in any category.
Note 1: This AD applies to each helicopter 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 helicopters that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (c) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition, or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any helicopter from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the shaft and subsequent loss of control
of the helicopter, accomplish the following:
(a) Prior to 200 hours time-in-service (TIS) since the assembly
of the hub and a shaft having zero hours TIS, and thereafter at
intervals not to exceed 100 hours TIS,
(1) Remove the shaft from the power train system.
(2) Clean and inspect the shaft for a crack in the area of the
six hub attach bolt (bolt) holes using a 10-power or higher
magnifying glass and bright light.
(3) If no crack is found, inspect the shaft using a direct or
indirect magnetic particle inspection method in accordance with ASTM
Standard No. E1444 as follows:
(i) For direct magnetization, use an AC, DC, or AC/DC wet
continuous method with fluorescent or nonfluorescent particles.
(A) Circular (Head Shot)--1,100 amperes
Look for a longitudinal crack.
(B) Longitudinal (Coil Shot)--Because of variations in coil
design, only the length-to-diameter ratio based on effective
diameter and inspection region is provided.
Effective diameter--1.279 inches,
Length--6.00 inches,
L/D Ratio--5,
Look for a circumferential crack.
(C) Demagnetize and clean the inspection areas with solvent to
remove residual particles.
(ii) For indirect magnetization, use an AC electromagnetic yoke
(Magnaflux product No. Y-6 or equivalent). Set the spacing and the
angle to suit the external diameter of the shaft.
(A) Magnetize each of the six hole areas by applying the AC
electromagnetic yoke (yoke) circumferentially across the hole.
(B) During each magnetization, apply dry color contrasting
particles to the inspection area and look for a circumferential
crack propagating from any hole.
(C) Demagnetize and repeat the inspections with the poles of the
yoke positioned longitudinally across each hole group looking for a
circumferential crack.
(D) Demagnetize and clean the inspection areas with solvent to
remove residual particles.
(iii) If no crack is found as a result of the magnetic particle
inspection, reassemble the hub and shaft.
Note 2: Procedures in Model 269D Handbook of Maintenance
Instructions (HMI) revised on June 12, 1998, include installing a
three-piece retention fitting, applying a higher torque to each
bolt, assembling with no lubricant, and applying zinc chromate
primer between the hub and the shaft.
(4) If a crack is found, replace the shaft with an airworthy
shaft.
(b) At intervals not to exceed 50 hours TIS after accomplishing
paragraph (a),
(1) Unsafety and clean the exterior of the bolts.
(2) Unsafety and loosen the droop stop nut.
(3) Apply 390 in-lbs of torque to each of the six bolts. If any
bolt rotates, accomplish the requirements of paragraph (a).
(4) Apply 390 to 410 in-lbs of torque to each of the six bolts
and resafety.
(5) Torque and safety the droop stop nut.
(6) Seal the exterior of the bolts and washers with a corrosion
preventative compound.
(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, New York Aircraft Certification
Office, FAA. Operators
[[Page 2823]]
shall submit their requests through an FAA Principal Maintenance
Inspector, who may concur or comment and then send it to the
Manager, New York Aircraft Certification Office.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the New York Aircraft Certification Office.
(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 helicopter to a location where
the requirements of this AD can be accomplished.
(e) This amendment becomes effective on February 3, 1999, to all
persons except those persons to whom it was made immediately
effective by Priority Letter AD 98-26-06, issued December 9, 1998,
which contained the requirements of this amendment.
Issued in Fort Worth, Texas, on January 8, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-1064 Filed 1-15-99; 8:45 am]
BILLING CODE 4910-13-P
