[Federal Register Volume 60, Number 102 (Friday, May 26, 1995)]
[Proposed Rules]
[Pages 27926-27932]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12955]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-SW-06-AD]
Airworthiness Directives; Robinson Helicopter Company Model R22
Series Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to Robinson Helicopter Company
Model R22 series helicopters, that currently requires an inspection and
repetitive visual checks for slippage of the tail rotor (T/R) drive and
replacement of the T/R gearbox, if necessary. This action would require
disassembly of the T/R gearbox to verify the installation of the input
and output shaft keys (keys) between the input and output pinions and
their respective shafts. This proposal is prompted by two incidents in
which the key was not installed between the output shaft and the output
pinion during assembly of the T/R gearbox at Robinson Helicopter
Company. The actions specified by the proposed AD are intended to
prevent slippage of the T/R drive, loss of directional control, and
subsequent loss of control of the helicopter.
DATES: Comments must be received by July 25, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 95-SW-06-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137. Comments may be inspected at this location between 9:00
a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Ms. Elizabeth Bumann, Aerospace
Engineer, FAA, Los Angeles Aircraft Certification Office, 3960
Paramount Blvd., [[Page 27927]] Lakewood, California 90712, telephone
(310) 627-5265, fax (310) 627-5210.
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 should 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 No. 95-SW-06-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, Office of the Assistant Chief Counsel, Attention: Rules
Docket No. 95-SW-06-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
Discussion
On August 25, 1994, the FAA issued priority letter AD 94-17-07,
applicable to Robinson Helicopter Company Model R22 series helicopters,
to require an inspection and repetitive visual checks for slippage of
the T/R drive and replacement of the T/R gearbox, if necessary. On
October 24, 1994, the FAA issued the final rule of the priority letter,
AD 94-17-07, Amendment 39-9059 (59 FR 55203, November 4, 1994). Those
actions were prompted by two incidents in which the key was not
installed between the output shaft and the output pinion during
assembly of the T/R gearbox. The key is required to prevent the output
gear from rotating on the output shaft. Both incidents resulted in
slippage of the T/R drive. The requirements of that AD are intended to
prevent slippage of the T/R drive, loss of directional control, and
subsequent loss of control of the helicopter. Owner/operator daily
preflight checks for misalignment of the alignment dots that are
installed on the tail cone skin and the drive shaft flange are allowed.
These owner/operator checks do not require the use of tools, precision
measuring equipment, training, pilot logbook endorsements, or the use
of technical data not contained in the AD. Additionally, these owner/
operator checks are considered part of the normal pilot ``Before
Takeoff'' and ``After Landing'' checks. These owner/operator checks are
additional measures to prevent slippage of the T/R drive until the
installation of the keys is verified. These checks may be performed by
an owner/operator holding at least a private pilot certificate, but
must be entered into the aircraft records showing compliance with this
AD in accordance with sections 43.11 and 91.417 (a)(2)(v) of the
Federal Aviation Regulations.
Since the issuance of that AD, the FAA has determined that the
required terminating action to AD 94-17-07 is verification of the
presence of both keys through disassembly and reassembly of the T/R
gearbox in accordance with the procedures contained in this notice, or
other FAA-approved procedures.
Since an unsafe condition has been identified that is likely to
exist or develop on other Robinson Helicopter Company Model R22 series
helicopters of the same type design, the proposed AD would supersede AD
94-17-07 to require disassembly of the T/R gearbox to verify the
installation of the key between the input and output pinions and their
respective shafts.
The FAA estimates that 500 helicopters of U.S. registry would be
affected by this proposed AD, that it would take approximately 5 work
hours per helicopter to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the proposed AD on U.S. operators is estimated to
be $150,000.
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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. 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 39-9059 (59 FR
55203, November 4, 1994), and by adding a new airworthiness directive
(AD), to read as follows:
Robinson Helicopter Company: Docket No. 95-SW-06-AD. Supersedes AD
94-17-07, Amendment 39-9059.
Applicability: Model R22 series helicopters, certificated in any
category with tail rotor (T/R) gearboxes that were manufactured or
overhauled by Robinson Helicopter Company prior to June 8, 1992. The
following gearbox serial numbers have been determined to have the T/
R input and output shaft keys installed and are therefore exempt
from this AD: 0012, 0013, 0014, 0020, 0021, 0040, 0054, 0062, 0091,
0095, 0098, 0108, 0121, 0134, 0137, 0153, 0169, 0179, 0185, 0191,
0201, 0205, 0227, 0228, 0235, 0248, 0258, 0262, 0272, 0277, 0280,
0321, 0333, 0342, 0365, 0432, 0439, 0444, 0503, 0504, 0525, 0548,
0558, 0559, 0565, 0574, 0576, 0592, 0594, 0597, 0603, 0604, 0605,
0615, 0632, 0641, 0644, 0650, 0656, 0662, 0663, 0674, 0686, 0689,
0696, 0697, 0700, 0702, 0707, 0722, 0734, 0735, 0736, 0742, 0759,
0767, 0777, 0778, 0805, 0832, 0836, 0839, 0842, 0850, 0862, 0866,
0868, 0887, 0892, 0937, 0939, 0983, 0986, 0996, 0998,
[[Page 27928]] 1018, 1021, 1029, 1030, 1035, 1072, 1081, 1087, 1104,
1116, 1121, 1126, 1129, 1132, 1141, 1151, 1176, 1186, 1187, 1199,
1205, 1208, 1217, 1222, 1228, 1233, 1245, 1249, 1269, 1274, 1290,
1293, 1299, 1301, 1307, 1311, 1323, 1330, 1333, 1339, 1341, 1350,
1361, 1379, 1385, 1388, 1392, 1404, 1412, 1428, 1438, 1442, 1450,
1460, 1468, 1494, 1499, 1505, 1509, 1512, 1514, 1526, 1541, 1544,
1578, 1586, 1593, 1595, 1597, 1605, 1610, 1627, 1628, 1636, 1643,
1647, 1648, 1652, 1654, 1686, 1687, 1698, 1701, 1702, 1706, 1710,
1724, 1731, 1732, 1738, 1741, 1750, 1752, 1757, 1759, 1769, 1783,
1800, 1803, 1808, 1814, 1816, 1830, 1844, 1846, 1851, 1852, 1861,
1868, 1871, 1886, 1889, 1901, 1911, 1912, 1927, 1928, 1948, 1959,
1961, 1963, 1965, 1992, 2025, 2034, 2037, 2051, 2071, 2100, 2101,
2103, 2126, 2129, 2136, 2160, 2166, 2170, 2180, 2193, 2203, 2242,
2254, 2265, 2269, 2272, 2279, 2280, 2283, 2294, 2298, 2299, 2304,
2314, 2357, 2377, 2380, 2381, 2395, 2406, 2420, 2421, 2422, 2423,
2425, 2431, 2435, 2436, 2459, 2479, 2492, 2498, 2531, 2539, 2574,
2579, 2582, 2587, 2627, 2634, 2672, 2683, 2697, 2716, 2719, 2721,
2731, 2797, 2863, 2937, 2945.
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 (d) 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 slippage of the T/R drive, loss of directional
control, and subsequent loss of control of the helicopter,
accomplish the following:
(a) Before further flight, install alignment dots as follows:
(1) Remove the transparent inspection cover on the tail cone and
rotate the T/R blades so that one blade leading edge is aligned with
the tail cone centerline. Mark a dot on the tail cone skin aligned
with the tip of the blade leading edge. With the same alignment,
mark a dot on the centerline of the tail cone skin at the edge of
the inspection hole, and mark a corresponding dot on the drive shaft
flange.
(2) Position the aft T/R blade with leading edge approximately
45-degrees above horizontal. Engage the clutch and rotor brake if
the helicopter is so equipped. Use the engine ring gear holding
tool, part number (P/N) MT091-1, or an FAA-approved equivalent, to
keep the engine from rotating.
(b) Conduct the following daily preflight checks for
misalignment of the alignment dots until compliance with paragraph
(c) of this AD has been accomplished: Check for misalignment of the
alignment dots installed on the tail cone skin and the drive shaft
flange by rotating the T/R blade so that the alignment dot is
visible in the inspection window and the tip of the T/R blade
leading edge aligns with the dot on the tail cone skin. Ensure that
the drive shaft flange dot is aligned with the dot on the centerline
of the tail cone skin at the edge of the inspection window. If any
misalignment is detected, before further flight, replace the T/R
gearbox with an airworthy one that has been determined to have both
the input and output keys installed in accordance with paragraph (c)
of this AD or other FAA-approved procedures, or is exempt from the
requirements of this AD as listed in the applicability section of
this AD. The checks required by this AD may be performed by an
owner/operator holding at least a private pilot certificate and must
be entered into the aircraft records showing compliance with this
AD, in accordance with sections 43.11 and 91.417(a)(2)(v) of the
Federal Aviation Regulations.
(c) Within the next 100 hours time-in-service (TIS) after the
effective date of this AD, or at the next annual inspection,
whichever occurs first, verify installation of both the input and
output shaft keys as follows:
(1) Cut and remove the safety wire securing the chip detector to
the sight gage on the T/R gearbox. Place a container under the T/R
gearbox to catch the drained oil and remove the chip detector.
Remove and discard the gasket on the chip detector.
(2) Remove the T/R gearbox from the helicopter in accordance
with the applicable maintenance manual.
(3) Cut and remove the safety wire securing the filler vent plug
to the sight gage on the T/R gearbox and remove the filler vent plug
and sight gage. Remove and discard the gasket on the filler vent
plug and sight gage.
(4) Remove and disassemble the output cartridge, P/N A111-1,
from the T/R gearbox case, P/N A109-1 (see figure 1) as follows:
(i) Place a mark across the gear case, P/N A109-1, and output
cartridge, P/N A111-1, with a felt pen or grease pencil to ensure
proper reassembly.
(ii) Cut and remove the safety wire around the four MS20074-04-
06 bolts, securing the output cartridge to the gear case. Remove the
four bolts and AN960-416L washer(s). Separate the output cartridge
from the gear case (see figure 1).
(iii) Remove and discard the safety wire, MS16562-24 or 52-022-
094-0437 roll pin, and MS14145L6 or LCN6M-624 retaining nut. Remove
the AN960-616L washer(s) and the washer, P/N A141-2, noting the
washer(s) location for reassembly. Do not damage the output shaft,
P/N A107-1, or the shim(s), P/N A118-1 through -6, located next to
the flange of the output cartridge when removing the retaining nut.
(iv) Visually inspect for the presence of the output shaft key,
P/N A114-2, between the pinion gear, P/N A545-1, and the output
shaft (see figure 2).
(v) If the output shaft key is missing, replace the T/R gearbox
with an airworthy one that has been determined to have the output
key installed. Report any T/R gearbox that has a missing key within
10 days after the inspection to the Manager, Los Angeles
Manufacturing Inspection Office, FAA, Northwest Mountain Region,
3960 Paramount Blvd., Lakewood, California 90712, telephone (310)
627-5290, fax (310) 627-5293. Reporting requirements have been
approved by the Office of Management and Budget and assigned OMB
control number 2120-0056.
(vi) If the output key is installed, reinstall the washer, P/N
A141-2, and AN960-616L washer(s). Install a MS14145L6 or LCN6M-624
retaining nut, and torque to 200-250 in.-lbs. plus 20-25 in.-lbs.
nut drag (maximum 275 in.-lbs.). Install a MS16562-24 or 52-022-094-
0437 roll pin, and safety wire using 0.032-inch stainless steel
safety wire. The safety wire pigtail must be wrapped tightly around
the retaining nut. Vibro-etch the final rule AD number on the output
cartridge attachment flange.
(5) Remove and disassemble the input cartridge, P/N A110-1, from
the T/R gear case, P/N A109-1, as follows:
(i) Place two marks across the gear case, P/N A109-1, and input
cartridge, P/N A110-1, with a felt pen or grease pencil to ensure
proper reassembly.
(ii) Cut and remove the safety wire around the four MS20074-04-
06 bolts securing the input cartridge to the gear case. Remove the
four bolts and AN960-416L washer(s). Separate the input cartridge
from the gear case (see figure 1).
(iii) Secure the input cartridge to a block of wood through the
two bolt holes in the input shaft assembly, P/N A116-1 (see figure
1). Place the block of wood in a vise. Remove and discard the safety
wire, roll pin, and retaining nut. Remove the AN960-616L washer(s),
and washer, P/N A141-1, noting the washer(s) location for
reassembly. Do not damage the input shaft or shim(s), P/N A118-1
through -6, located next to the flange of the input cartridge.
(iv) Visually inspect for the presence of the input shaft key,
P/N A114-1, between the gear, P/N A545-2, and the input shaft (see
Note on figure 2).
(v) If the input shaft key is missing, replace the T/R gearbox
with an airworthy one that has been determined to have the input key
installed. Report any T/R gearbox that has a missing key within 10
days after the inspection to the Manager, Los Angeles Manufacturing
Inspection District Office, FAA, Northwest Mountain Region, 3960
Paramount Blvd., Lakewood, California 90712, telephone (310) 627-
5290, fax (310) 627-5293. Reporting requirements have been approved
by the Office of Management and Budget, and assigned OMB control
number 2120-0056.
(vi) If the input key is installed, reinstall the AN960-616L
washer(s) and washer, P/N A141-1. Install a MS14145L6 or LCN6M-624
retaining nut, and torque to 200-250 in.-lbs. plus 20-25 in.-lbs.
nut drag (maximum 275 in.-lbs.). Install a MS16562-24 or 52-022-094-
0437 roll pin and safety wire using 0.032-inch stainless steel
safety wire. The safety wire pigtail must be wrapped tightly around
the retaining nut. Remove the two [[Page 27929]] bolts securing the
input shaft assembly to the block of wood. Vibro-etch the final rule
AD number on the input cartridge attachment flange.
(6) Reassemble the input and output cartridges to the T/R case
as follows:
(i) Color the ``X'' marked on the pinion gear, P/N A545-1, (one
tooth only) of the output cartridge and on the gear, P/N A545-2,
(located on two consecutive teeth) of the input cartridge with a red
marker to make reinstallation easier. Note that these three gear
teeth may already be colored (see figure 3).
(ii) Visually inspect the edge of the chamfers in the gear case,
making sure they are round and smooth so that the O-ring will not be
damaged upon installation.
(iii) Remove and discard the O-ring on both the input cartridge
and output cartridge. Replace the O-ring with National P/N AS142
B46-70, or Parker P/N 2-142 N674-70 O-ring. Lubricate the
replacement O-ring with oil, P/N A257-2, and install an O-ring on
each cartridge.
(iv) Reinstall the output cartridge on the gear case with four
MS20074-04-06 bolts and AN960-416L washers. Reinstall the input
cartridge on the gear case with four MS20074-04-06 bolts and AN960-
416L washers. Do not torque the bolts.
(v) Look through the sight gage opening while using a flashlight
pointed into the filler vent hole to verify the gears are meshed
properly. Gears are properly meshed when the ``X'' marked on the
pinion gear of the output cartridge is between the two ``X's''
marked on the gear of the input cartridge (see figure 3). Do not
torque the bolts until both cartridges are installed on the case and
the gears are properly meshed. Torque the output cartridge first,
then the input cartridge to 60 in.-lbs. Safety wire with 0.032-inch
stainless steel safety wire.
(vi) Reinstall sight gage with MS35769-11 or AN900-10 gasket.
Oil threads to prevent threads from locking up. Torque to 200 in.-
lbs.
(vii) Reinstall the chip detector with a MS35769-8 or AN900-9
gasket after lubricating the threads with oil. Torque the chip
detector to 150 in.-lbs. Safety wire the sight gage to the chip
detector using 0.032-inch stainless steel safety wire.
(viii) Fill the T/R gearbox with oil to the level indicated on
the T/R sight glass decal. Reinstall the filler vent plug, P/N A610-
1, with a MS35769-9 or AN900-8 gasket, after lubricating the threads
with oil.
(ix) Inspect the T/R gearbox assembly to ensure that the shafts
and gears rotate freely.
(7) Reinstall the T/R gearbox onto the helicopter in accordance
with the applicable maintenance manual. Verify that the oil level of
the T/R gearbox is at the recommended mark on the sight glass.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used when approved by the Manager, Los Angeles Aircraft
Certification Office, FAA. Operators shall submit their requests
through an FAA Principal Maintenance Inspector, who may concur or
comment and then send it to the Manager, Los Angeles Aircraft
Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles Aircraft Certification Office.
(e) 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.
BILLING CODE 4910-13-P
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BILLING CODE 4910-13-C
Issued in Fort Worth, Texas, on May 19, 1995.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certificatin Service.
[FR Doc. 95-12955 Filed 5-25-95; 8:45 am]
BILLING CODE 4910-13-P
