[Federal Register Volume 66, Number 25 (Tuesday, February 6, 2001)]
[Rules and Regulations]
[Pages 9031-9034]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-3103]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-SW-02-AD; Amendment 39-12100; AD 2001-01-52]
RIN 2120-AA64


Airworthiness Directives; Bell Helicopter Textron Canada Model 
407 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) 2001-01-52, which was sent 
previously to all known U.S. owners and operators of Bell Helicopter 
Textron Canada (BHTC) Model 407 helicopters by individual letters. This 
AD requires, before further flight, reducing the maximum approved never 
exceed velocity (Vne); inserting a copy of this AD into the Rotorcraft 
Flight Manual (RFM); installing a temporary placard on the flight 
instrument panel to indicate the reduced Vne limit; and installing a 
new redline Vne limit on all airspeed indicators. This amendment is 
prompted by an accident resulting from a suspected tail rotor strike to 
the tailboom. The actions specified by this AD are intended to prevent 
tail rotor blades from striking the tailboom, separation of the aft 
section of the tailboom with the tail rotor gearbox and vertical fin, 
and subsequent loss of control of the helicopter.

DATES: Effective February 21, 2001, to all persons except those persons 
to whom it was made immediately effective by Emergency AD 2001-01-52, 
issued on January 10, 2001, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before April 9, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 9032]]

Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2001-SW-02-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: [email protected].

FOR FURTHER INFORMATION CONTACT: Sharon Miles, Aviation Safety 
Engineer, FAA, Rotorcraft Directorate, Regulations Group, Fort Worth, 
Texas 76193-0111, telephone (817) 222-5122, fax (817) 222-5961.

SUPPLEMENTARY INFORMATION: On September 25, 1998, the FAA issued 
Priority Letter AD 98-20-41, Docket No. 98-SW-53-AD, for BHTC Model 407 
helicopters, which restricted the airspeed to 25 knots indicated 
airspeed (KIAS) less than the Vne airspeeds indicated on the airspeed 
limitation placard. The priority letter also required installing an 
airspeed limitation placard; marking a redline at a Vne of 115 KIAS; 
applying a red arc from 115 to 140 KIAS on all airspeed indicators; and 
revising the Limitations section of the RFM that requires pilots to 
maintain yaw trim within one ball width of the centered position of the 
turn and bank (slip) indicator. That action was prompted by two 
accidents involving in-flight tail rotor blade strikes against the 
tailboom on BHTC Model 407 helicopters. Persons aboard both helicopters 
reported hearing a loud ``bang'' immediately before losing directional 
control of the helicopter. Subsequent inspection of the helicopters 
revealed that the aft section of the tailboom, including the tail 
rotor, the tail rotor gearbox, and the vertical fin, had separated from 
the helicopters in-flight. In both cases, inspection of the retrieved 
tailbooms confirmed that the tailbooms had been struck at least three 
times by the rotating tail rotor blades. The specific cause of these 
two in-flight tail rotor blade strikes against the tailboom has not 
been determined; however, flight test data indicated that tail rotor 
blade strikes were more likely to occur at higher airspeeds and 
altitudes. The data indicated that the cause of the tail rotor strikes 
may be excessive tail rotor blade flapping. Tail rotor blade flapping 
may be aggravated by left pedal input. Excessive tail rotor flapping, 
if not corrected, could result in the tail rotor blades striking the 
tailboom, separation of the aft section of the tailboom with the tail 
rotor gearbox and vertical fin, and subsequent loss of control of the 
helicopter. Transport Canada, which is the airworthiness authority for 
Canada, issued AD CF-98-36, dated September 25, 1998, to require that 
the airspeed be reduced to minimize the risk of a tailboom strike 
during flight.
    After issuing Priority Letter AD 98-20-41, BHTC issued Technical 
Bulletin No. 407-98-13, dated December 12, 1998 (TB), which recommended 
a reduction in Vne of only 15 KIAS with the installation of a left 
pedal stop to limit maximum tail rotor blade pitch. Transport Canada 
notified the FAA that an unsafe condition may continue to exist on BHTC 
Model 407 helicopters. Transport Canada advised that installing the 
tail rotor pitch-limiting left-pedal stop in accordance with the TB and 
further reducing the Vne were required to minimize the risk of a 
tailboom strike during flight. Transport Canada classified the TB as 
mandatory, and issued AD CF-98-36R3, dated March 5, 1999, to ensure the 
continued airworthiness of these helicopters in Canada. That action was 
prompted by a third accident involving an in-flight tail rotor blade 
strike against the tailboom on BHTC Model 407 helicopters. The pilot in 
that accident reported that the helicopter was in straight and level 
cruise flight at 110 KIAS in non-turbulent conditions when the 
helicopter experienced an uncommanded left pedal hardover. The pilot 
reported that this uncommanded full left pedal movement was followed by 
a loud ``bang'' and then a loss of directional control of the 
helicopter. Subsequent inspection of the helicopter revealed that the 
aft section of the tailboom, including the tail rotor, the tail rotor 
gearbox, and the vertical fin, had separated from the helicopter in-
flight. The helicopter did not have the tail rotor pitch-limiting left-
pedal stop installed.
    As a result of BHTC issuing the TB and because of the additional 
accident, the FAA issued Priority Letter AD 99-06-15, Docket No. 99-SW-
16-AD, on March 9, 1999, that superseded Priority Letter AD 98-20-41. 
AD 99-06-15 was published in the Federal Register as Amendment 39-11111 
(64 FR 16801, April 7, 1999). AD 99-06-15 required, before further 
flight, installing a tail rotor pitch-limiting left-pedal stop and 
adjusting the rigging of the directional controls; installing a new 
airspeed limitation placard; marking a new Vne limit of 100 KIAS on all 
airspeed indicators; and revising the RFM to reduce the airspeed 
limitation further and to maintain the previously revised yaw-
operational limitations. The AD was intended to prevent the tail rotor 
blades from striking the tailboom, which could result in separation of 
the aft section of the tailboom with the tail rotor gearbox and 
vertical fin, and subsequent loss of control of the helicopter.
    After the FAA issued AD 99-06-15, the manufacturer made a design 
change to the tail rotor system to eliminate tail rotor strikes to the 
tailboom and also made design changes to the pedal stop. Subsequently, 
the FAA issued superseding AD 2000-14-16, Docket No. 2000-SW-10-AD (65 
FR 45703, July 25, 2000) which requires, before further flight after 
January 31, 2001, installing a redesigned tail rotor system and 
modifying the vertical fin and horizontal stabilizer to allow restoring 
the Vne to 140 KIAS.
    Since the issuance of that AD, there has been an accident in which 
a helicopter flying at approximately 140 KIAS was destroyed on water 
impact following an in-flight occurrence. One of the suspected 
contributing factors is an in-flight tail rotor strike to the tailboom. 
As a precautionary measure, pending further investigation into the 
accident and before the suspected in-flight tail rotor strike can be 
confirmed or eliminated, Transport Canada issued AD No. CF-2001-01, 
dated January 8, 2001, to reduce Vne speed. The FAA agrees with this 
precautionary measure.
    Since the unsafe condition described is likely to exist or develop 
on other BHTC Model 407 helicopters of the same type design, the FAA 
issued Emergency AD 2001-01-52 to prevent tail rotor blades from 
striking the tailboom, separation of the aft section of the tailboom 
with the tail rotor gearbox and vertical fin, and subsequent loss of 
control of the helicopter. The AD requires the following before further 
flight:
     Reducing the maximum approved Vne to 100 KIAS if an 
airspeed actuated pedal stop is not installed or to 110 KIAS if an 
airspeed actuated pedal stop is installed;
     Inserting a copy of this AD into the RFM;
     Installing a temporary placard on the flight instrument 
panel to indicate the reduced Vne limit; and
     Installing a new redline Vne limit at either 100 or 110 
KIAS, as applicable, on all airspeed indicators.
    The short compliance time involved is required because the 
previously described critical unsafe condition can adversely affect the 
structural integrity of the helicopter. Therefore, the actions 
previously listed are required before 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

[[Page 9033]]

good cause existed to make the AD effective immediately by individual 
letters issued on January 10, 2001, to all known U.S. owners and 
operators of BHTC Model 407 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. However, there was an error in 
paragraphs (a) and (b) of the emergency AD. The word ``minimum'' was 
inadvertently used when the intent was to use the word ``maximum.'' The 
correction is made in this AD; the FAA has determined that this change 
will neither increase the economic burden on an operator nor increase 
the scope of the AD.
    The FAA estimates that 200 helicopters of U.S. registry will be 
affected by this AD. It will take approximately 3 work hours per 
helicopter to manufacture and install each airspeed limitation placard. 
The average labor rate is $60 per work hour. Required parts will cost 
approximately $10 per helicopter. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $38,000 to 
install an airspeed limitation placard on all helicopters in the U.S. 
fleet.

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 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 mailed 
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. 2001-SW-02-AD.'' The postcard will be date 
stamped and returned to the commenter.
    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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 
FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham 
Blvd., Room 663, Fort Worth, Texas 76137.

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:

2001-01-52  Bell Helicopter Textron Canada: Amendment 39-12100. 
Docket No. 2001-SW-02-AD.

    Applicability: Model 407 helicopters, certificated in any 
category.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 request approval for an 
alternative method of compliance in accordance with paragraph (f) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required before further flight, unless accomplished 
previously.
    To prevent the tail rotor blades from striking the tailboom, 
separation of the aft section of the tailboom with the tail rotor 
gearbox and vertical fin, and subsequent loss of control of the 
helicopter, accomplish the following:
    (a) For helicopters that do not have an airspeed actuated pedal 
stop installed, reduce the maximum approved placarded never exceed 
velocity (Vne) to 100 knots indicated airspeed (KIAS) except in 
autorotation where it remains 100 KIAS maximum or where the basic 
flight manual or operation installation limitations indicate less 
than these values.
    (b) For helicopters that have an airspeed actuated pedal stop 
installed, reduce the maximum approved placarded Vne to 110 KIAS 
except in autorotation where it remains 100 KIAS maximum or where 
the basic flight manual or operation installation limitations 
indicate less than these values.
    (c) Insert a copy of this AD into the Rotorcraft Flight Manual 
(BHT-407-FM-1) at the front of the Flight Limitations Section.
    (d) Install a temporary locally manufactured placard on the 
flight instrument panel over the existing Vne placard to indicate 
the new Vne limit specified in paragraph (a) or (b) of this AD.
    (e) Install a new redline Vne limit at either 100 or 110 KIAS on 
all airspeed indicators, corresponding to the new limit specified in 
the appropriate paragraph of this AD. Obscure or remove all previous 
redline limits. If the new redline is installed on the instrument 
glass, also install a slippage mark on the glass and on the 
instrument case.
    (f) 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, Regulations Group, Rotorcraft 
Directorate, FAA. Operators shall submit their requests through an 
FAA Principal Maintenance Inspector, who may concur or comment and 
then send it to the Manager, Regulations Group.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Regulations Group.


[[Page 9034]]


    (g) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the helicopter to a location where 
the requirements of this AD can be accomplished provided that the 
Vne limits specified in this AD are not exceeded.
    (h) This amendment becomes effective on February 21, 2001, to 
all persons except those persons to whom it was made immediately 
effective by Emergency AD 2001-01-52, issued January 10, 2001, which 
contained the requirements of this amendment.

    Note 3: The subject of this AD is addressed in Transport Canada 
(Canada) AD No. CF-2001-01, dated January 8, 2001.


    Issued in Fort Worth, Texas, on January 30, 2001.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 01-3103 Filed 2-5-01; 8:45 am]
BILLING CODE 4910-13-P