[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.

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    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