AD 96-11-08

[Federal Register Volume 61, Number 103 (Tuesday, May 28, 1996)]
[Rules and Regulations]
[Pages 26429-26431]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-13206]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-SW-27-AD, Amendment 39-9633; AD 96-11-08]
RIN 2120-AA64


Airworthiness Directives; Robinson Helicopter Company Model R22 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Robinson Helicopter Company (Robinson) Model R22 
helicopters, that currently requires installing a low-rotor RPM caution 
light and resetting the low-RPM warning unit to activate the warning 
horn and caution light at 94% to 96% revolutions-per-minute (RPM). This 
amendment requires installation of an improved throttle governor; an 
adjustment to the low RPM warning unit threshold to increase the RPM at 
which the warning horn and caution light activate; and, revisions to 
the R22 Rotorcraft Flight Manual that prohibit flight with the improved 
throttle governor selected off, except in certain situations. This 
amendment is prompted by an FAA Technical Panel review of Model R22 
accident history data which revealed that main rotor (M/R) blade stall 
at abnormally low M/R RPM resulted in accidents. The actions specified 
by this AD are intended to minimize the possibility of pilot 
mismanagement of the M/R RPM, which could result in unrecoverable M/R 
blade stall and subsequent loss of control of the helicopter.

EFFECTIVE DATE: July 2, 1996.

FOR FURTHER INFORMATION CONTACT: Ms. Elizabeth Bumann, Aerospace 
Engineer, FAA, Los Angeles Aircraft Certification Office, 3960 
Paramount Blvd., Lakewood, California 90712-4137, telephone (310) 627-
5265; fax (310) 627-5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 82-23-51, 
Amendment 39-4645, (48 FR 21894, May 16, 1983), which is applicable to 
Robinson Helicopter Model R22 helicopters, was published in the Federal 
Register on December 14, 1995 (60 FR 64129). That action proposed to 
require installation of an improved throttle governor; an adjustment to 
the warning unit threshold to increase the RPM at which the warning 
horn and caution light activate; and, revisions to the R22 Rotorcraft 
Flight Manual.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Discussion of Comments

    Eight commenters responded to the NPRM. These commenters are the 
National Transportation Safety Board (NTSB), Helicopter Association 
International (HAI), Helicopter Association of Australia, Civil 
Aviation Safety Authority Australia, the Robinson Helicopter 
Association, the manufacturer, and two helicopter operators. Comments 
were received on the proposal to increase the threshold of the low 
rotor RPM warning unit, the proposal to require installation of the 
improved throttle governor, the proposal to limit operations with the 
governor selected off, and proposed Rotorcraft Flight Manual (RFM) 
changes and other general comments. The commenters' positions and the 
FAA response to each of these positions are summarized as follows:

Increase in Threshold of Warning Unit

    Three commenters support and no commenters object to the proposal 
to increase the low rotor RPM warning unit horn and caution light 
threshold from 951% RPM to between 96% and 97% RPM. 
Therefore, the proposal is adopted as proposed.

Installation of Improved Throttle Governor

    Three commenters support and five commenters oppose the proposal to 
require installation of a throttle governor on all Model R22 
helicopters. The two commenters from Australia oppose mandating 
installation of a throttle governor and state that although the 
throttle governor would reduce pilot workload and enhance public 
safety, mandatory installation of the governor is unnecessary since no 
conclusive evidence exists to indicate that a Model R22 accident in 
their country was caused by abnormally low RPM. Therefore, very few 
accidents would have been prevented with a governor installed. 
Additionally, these two commenters suggest that the FAA allow more time 
to determine whether implementation of Special Federal Aviation 
Regulation (SFAR 73) on March 27, 1995, mandating awareness training 
for low time pilots and special training requirements for flight 
instructors, will necessitate any further safety action.
    Another commenter states that the improved throttle governor is not 
necessary based upon their analysis of the National Transportation 
Safety Board (NTSB) accident data for the Model R22 from January 1992 
to December 1995. The commenter noted that the overall number of R22 
accidents declined with the implementation of SFAR 73 and the issuance 
of Airworthiness Directive 95-11-09, effective July 14, 1995, 
prohibiting low ``g'' maneuvers.
    Another commenter states that recent accident statistics show that 
no R22 accident in 1995 could be attributed to low rotor RPM. The 
commenter states that the awareness training has had a positive effect 
and that mechanical solutions should be deleted or put on hold until 
evidence is available which indicates that the proposed changes are 
necessary.
    A fifth commenter states that the proposal to require installation 
of the improved throttle governor may not increase safety in any way 
and may cause additional accidents since some low time pilots may 
become too reliant on the governor and not realize other difficulties 
such as carburetor icing.
    The FAA does not concur. Although accident data presented indicates 
that low rotor stall due to improper throttle management has not 
resulted in recent R22 accidents, several of the 31 fatal accidents in 
the period from 1981 to the present involving main rotor to fuselage 
contact have exhibited signs of low rotor stall due to low rotor RPM. 
Accident records provided by the NTSB indicate that there were 33 non-
fatal accidents in a 10 year period, from June 1985 to June 1995, in 
which failure to maintain rotor RPM was a casual factor. These 
accidents all resulted in at least substantial damage to the airframe. 
The FAA's recently completed study indicates that the potential exists 
for these types of accidents due to throttle mismanagement. 
Installation of the improved throttle governor will reduce the 
possibility of throttle mismanagement.
    Even with the improved training, as stipulated in SFAR 73, the 
possibility of M/R stall due to throttle mismanagement still exists. 
The current

[[Page 26430]]

R22 fleet consists of helicopters that have no governors, and that have 
either throttle/collective governors or throttle governors. The FAA 
considers issuance of this AD to be necessary due to the different 
operating characteristics and associated safety implications of this 
mixed fleet, particularly in the training environment. The differences 
in flight operating characteristics between the governor configurations 
are significant and could cause confusion and an unsafe condition for 
students and low-time pilots, especially while operating in adverse 
flying conditions. Based on these safety concerns, the proposal to 
install or upgrade, as appropriate, a governor on the Model R22 
helicopters is adopted as proposed.
    Another commenter, although supportive of the proposal to require a 
throttle governor, states that installation of a governor caution light 
should be mandatory to indicate governor failure.
    The FAA does not concur. A governor caution light is not necessary 
since the main rotor RPM gage and low rotor RPM warning horn and light 
should provide sufficient information to the pilot to indicate that a 
governor failure has occurred. This suggestion is beyond the scope of 
the proposal, is unecessary, and is not adopted.

Operations With the Governor Selected Off

    One commenter supports the proposed rule to prohibit flight with 
the throttle governor selected off, except for system malfunction and 
emergency procedures training with an instructor pilot. Three 
commenters oppose this action.
    Two commenters state that pilots should be allowed to operate 
without the throttle governor during all dual training operations with 
a qualified helicopter flight instructor to ensure the continuing 
acceptance of the R22 helicopter as a generic piston helicopter 
trainer.
    The FAA does not concur. The FAA considers flight with the governor 
off to be emergency procedures training and disagrees that the governor 
should remain off during all flight with a qualified flight instructor 
to support training for flight in other piston helicopters.
    One commenter states that the proposed action is too restrictive 
and may have a negative impact on safety in that it precludes low-time 
pilots from continuing to reinforce their training through hands-on 
flying.
    The FAA does not concur. The proposed action does not preclude a 
low time pilot from practicing flight with the governor selected off 
when that pilot is with an instructor. Therefore, there is still the 
opportunity to continue to reinforce flight training with the governor 
selected off.

RFM Changes and Other General Comments

    The manufacturer comments that the R22 Rotorcraft Flight Manual 
(RFM) requires the governor be selected off for autorotations. It 
further states that a high time experienced pilot should be able to 
practice autorotations without an instructor.
    The FAA concurs. Pilots should be able to reinforce their training 
by practicing maneuvers in which they have already demonstrated 
proficiency. Persons who have received an endorsement from a certified 
flight instructor to act as a pilot in command of a Robinson R22 
helicopter should be allowed to practice emergency procedures training 
without the assistance of a flight instructor. This final rule is 
revised to require the Flight and Maneuver Limitations section of the 
R22 RFM to read ``Flight prohibited with governor selected off, with 
exceptions for inflight system malfunction or emergency procedures 
training.''
    The manufacturer states that the cost estimate in the proposal is 
$1,000,000 too high, since only one-half of the 1, 014 helicopters will 
require the complete governor at a cost of $2,150 per helicopter.
    The costs stated in the proposal are estimates. Since it is unknown 
how many Model R22's will require the upgrade to the throttle/
collective governor, there are no data to support a change and 
therefore the estimated total cost in the proposal will remain 
unchanged.
    The manufacturer also states that the reference to the July 6, 1995 
date, the revision date of the Rotorcraft Flight Manual (RFM), in 
paragraph (d) of the NPRM should be omitted. Additionally, the 
manufacturer states that the requirement to add page 2-2 to the FAA 
approved R22 RFM is not appropriate since it is already in the earlier 
revision to the RFM and is not related to the proposed actions.
    The FAA concurs. Changes to page 2-2 of the FAA approved RFM, 
revised July 6, 1995, do not pertain to the actions of this AD. 
Therefore, the reference to page 2-2 of the RFM is omitted in this 
final rule. Also, since the proposal indicated that page 2-7 would be 
inserted into the RFM, it was necessary to state the revision date, 
July 6, 1995, of that change. However, this final rule only requires 
that a specific statement be inserted into the Flight and Maneuver 
Limitations section of the RFM and not that the manufacturer centss 
specific revised page be inserted into the RFM; hence, the revision 
date of July 6, 1995 is no longer needed. Therefore, with the exception 
of omitting the reference to page 2-2 and reorganization of the 
requirement to add a statement to the Flight and Maneuver Limitations 
section of the RFM, this action is adopted as proposed.
    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 rules as proposed except for 
revisions to paragraph (d) to delete the words ``with an instructor 
pilot'' from the requirement ``flight prohibited with governor selected 
off, with exceptions for inflight system malfunction or emergency 
procedures training with an instructor pilot,'' deletion of page 2-2 as 
referenced, and deletion of the reference to page 2-7.
    The FAA estimates that 1,014 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 8 work hours to 
install the improved throttle governor, or 7 hours to upgrade the 
throttle/collective governor, and approximately 0.2 work hour to 
accomplish the adjustment of the light/warning horn RPM, and that the 
average labor rate is $60 per work hour. Required parts will cost 
approximately $2,150 per helicopter to install the improved throttle 
governor, or approximately $500 for upgrading the throttle/collective 
governor per helicopter. Based on these figures, the total cost impact 
of the AD on U.S. operators is estimated to be $2,678,988. This cost 
estimate assumes that no helicopters are currently equipped with a 
governor and all will need the improved throttle governor installed.
    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

[[Page 26431]]

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, 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 removing Amendment 39-4645 (48 FR 
21894, May 16, 1983), and by adding a new airworthiness directive (AD), 
Amendment 39-9633, to read as follows:

AD 96-11-08  Robinson Helicopter Company: Amendment 39-9633. Docket 
No. 95-SW-27-AD. Supersedes AD 82-23-51, Amendment 39-4645.

    Applicability: Model R22 helicopters, serial numbers (S/N) 0002 
to 2537, 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 (e) 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 within 30 days after the effective date of 
this AD, unless accomplished previously.
    To minimize the possibility of pilot mismanagement of the main 
rotor (M/R) revolutions-per-minute (RPM), which could result in 
unrecoverable M/R blade stall and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) Adjust the A569-1 or -5 low-RPM warning unit so that the 
warning horn and caution light activate when the M/R RPM is between 
96% and 97% rotor RPM in accordance with the procedures contained in 
the Model R22 maintenance manual.
    (b) For Model R22 helicopters that do not have a governor 
currently installed, install a Robinson Helicopter Company KI-67-2 
Governor Field Installation Kit in accordance with the kit 
instructions.
    (c) For Model R22 helicopters that have a throttle/collective 
governor currently installed, upgrade the governor with a Robinson 
Helicopter Company KI-67-3 Governor Upgrade Kit in accordance with 
the kit instructions.
    (d) Upon accomplishment of paragraphs (b) or (c) of this AD, 
revise the FAA-approved Robinson Helicopter Company R22 Rotorcraft 
Flight Manual (RFM) to include the following statement in the Flight 
and Maneuver Limitations section. This may be accomplished by 
inserting a copy of this AD into the RFM.
    ``Flight prohibited with governor selected off, with exceptions 
for inflight system malfunction or emergency procedures training.''
    (e) 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, Los Angeles Aircraft Certification 
Office, FAA. Operators shall submit their requests through FAA 
Principal Maintenance Inspectors, 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.

    (f) 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.

    Issued in Fort Worth, Texas, on May 15, 1996.
Daniel P. Salvano,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 96-13206 Filed 5-24-96; 8:45 am]
BILLING CODE 4910-13-P