Federal Register / Vol. 61, No. 19 / Monday, January 29, 1996 / Rules and Regulations 2705

of the Federal Aviation Regulations (14 CFR

21.197 and 21.199) to operate the aircraft to

a location where the requirements of this AD

can be accomplished.

(e) This amendment supersedes priority

letter AD 94–11–11, issued June 23, 1994.

(f) This amendment becomes effective on

February 13, 1996.

Issued in Burlington, Massachusetts, on

January 11, 1996.

Jay J. Pardee,

Manager, Engine and Propeller Directorate,

Aircraft Certification Service.

[FR Doc. 96–1410 Filed 1–26–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 95–NM–19–AD; Amendment

39–9501; AD 96–03–04]

Airworthiness Directives; General

Dynamics (Convair) Model 240 Series

Airplanes, Including Model T–29

(Military) Airplanes; Model 340 and 440

Series Airplanes; and Model C–131

(Military) Airplanes; Including Those

Modified for Turbo-Propeller Power

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to various General Dynamics

(Convair) airplanes, that requires

revising the Airplane Flight Manual to

require that the flight crew limit the flap

settings during certain icing conditions

and air temperatures. This amendment

is prompted by reports indicating that

incidents involving uncommanded

pitch excursions have occurred due to

ice contaminated tailplane stall (ICTS)

that occurred during or following flight

in icing conditions. If flap settings are

increased for landing when conditions

for ICT S are present, elevator control

could be affected adversely and the

airplane could descend uncontrollably.

The actions specified by this AD are

intended to ensure that the flight crew

is advised of the potential hazard

related to increasing the flap settings

when conditions for ICTS are present,

and the procedures necessary to address

it.

EFFECTIVE DATE: February 28, 1996.

ADDRESSES: Information pertaining to

this rulemaking action may be examined

at the Federal Aviation Administration

(FAA), Transport Airplane Directorate,

Rules Docket, 1601 Lind Avenue SW.,

Renton, Washington; or at the FAA, Los

Angeles Aircraft Certification Office,

Transport Airplane Directorate, 3960

Paramount Boulevard, Lakewood,

California.

FOR FURTHER INFORMATION CONTACT:

Andrew Gfrerer, Aerospace Engineer,

Systems and Equipment Branch, ANM–

130L, FAA, Transport Airplane

Directorate, Los Angeles Aircraft

Certification Office, 3960 Paramount

Boulevard, Lakewood, California 90712;

telephone (310) 627–5338; fax (310)

627–5210.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to

include an airworthiness directive (AD)

that is applicable to various General

Dynamics (Convair) airplanes was

published in the Federal Register on

June 16, 1995 (60 FR 31648). That action

proposed to require revising the FAAapproved Airplane Flight Manual

(AFM) to require that the flight crew

limit the flap settings during certain

icing conditions and air temperatures.

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

comments received.

One commenter supports the

proposed rule.

One commenter supports the

proposed rule, but believes that an

allowance should be made for using a

setting of greater than flaps 30 after

icing conditions have been encountered

if outside air temperatures in the

landing area are well above freezing.

The commenter indicates that icing

conditions may be encountered at

cruising altitudes, but the ground

temperatures could be much warmer.

The commenter believes that there is

virtually no chance that ice would

remain on the tail. From the

commenter’s experience, all ice that has

collected on the wing leading edges,

engine nacelles, windscreens, and

windshield wipers will have

disappeared by the time the indicating

outside air temperature has reached +5

degrees Celsius on descent.

In light of these remarks, the

commenter suggests that the AFM

revision required by paragraph (a) of the

proposed rule be reworded as follows:

‘‘Flap selection is limited to a

maximum of 30 degrees after icing

conditions have been encountered if the

indicated OAT on approach is +5

degrees Celsius or lower; or if icing

conditions are anticipated during

approach and landing; or when the

outside air temperature is +5 degrees

Celsius or below and any visible

moisture is present.’’

The FAA does not concur with the

commenter’s suggestion. Operators

cannot generally assume that accreted

ice will not be present on wings and

tailplanes if the outside air temperatures

are above +5 degrees Celsius on

approach. Ice sublimation, melting, and

shedding are not only functions of

temperature, but also are dependent

upon other factors such as the nature,

size, and extent of ice accretion;

operation of ice protection systems; time

of flight in temperatures above freezing;

and airplane speed.

The commenter’s concern regarding

incurring a flap extension limitation

after encountering, and then departing,

icing conditions has merit. However, the

airplane must be free of ice before the

flaps are extended to greater than 30

degrees. Since ice can accrete on

tailplanes with a small leading edge

radius when there is no evidence of ice

accretion on the wings, a method of

visual inspection of the wings,

tailplanes, and/or proven ice detectors

or ice evidence probes would be

necessary to assure clean surfaces.

One commenter requests that the

proposed AD be withdrawn. The

commenter states that the airplane can

be operated quite safely within the

environment to which it is certified

when the anti-icing system is

operational and functioning, and when

that system is used in the manner in

which it was intended.

The FAA does not concur with the

commenter’s request. Test pilots of

Convair Model 5800 series airplanes

actually experienced evidence of ice

contaminated tailplane stall (ICTS)

during pushover maneuver flight tests.

(Model 5800 series airplanes are similar

to Model 340 series airplanes equipped

with turbo-prop engines.) For this

reason the type certificate holder agreed

with the FAA that a flap extension

restriction during operation in icing

conditions is necessary. The specific

flight test used to determine

susceptibility to ICTS is a pushover

maneuver to generate an increased angle

of attack on the horizontal tailplane.

This maneuver is performed with ice

shapes on the tailplane and flaps in

approach and landing positions, at

speeds from near approach to maximum

for the configurations. The test

procedure requires a push force

throughout the maneuver to zero load

factor. A force reversal would be

indicative of an elevator hinge moment

reversal caused by airflow separation

due to accreted ice and an increased

angle of attack due to pitch rate, and

would define the aircraft as susceptible

to ICTS. Because all affected Convair

airplane models have tailplane designs

that are similar to the model tested, this

AD requires a flap limitation.

The FAA has revised this final rule to

clarify that the unsafe condition
2706 Federal Register / Vol. 61, No. 19 / Monday, January 29, 1996 / Rules and Regulations

specified in this AD can occur if the flap

settings are increased when conditions

for ICTS are present.

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 rule as proposed.

There are approximately 282 Model

240 series airplanes, including Model

T–29 (military) airplanes; Model 340

and 440 series airplanes; Model C–131

(military) airplanes, and those models

modified for turbo-propeller power; of

the affected design in the worldwide

fleet. The FAA estimates that 197

airplanes of U.S. registry will be affected

by this AD, that it will take

approximately 1 work hour per airplane

to accomplish the required actions, and

that the average labor rate is $60 per

work hour. Based on these figures, the

cost impact of the AD on U.S. operators

is estimated to be $11,820, or $60 per

airplane.

The cost impact figure discussed

above is based on assumptions that no

operator has yet accomplished any of

the requirements of this AD action, and

that no operator would accomplish

those actions in the future if this AD

were not adopted.

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

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

96–03–04 General Dynamics (Convair):

Amendment 39–9501. Docket 95–NM–

19–AD.

Applicability: All Model 240 series

airplanes, including Model T–29 (military)

airplanes; Model 340 and 440 series

airplanes; and Model C–131 (military)

airplanes; including those models modified

for turbo-propeller power (commonly

referred to as Model 580, 600, and 640 series

airplanes); certificated in any category.

Compliance: Required as indicated, unless

accomplished previously.

To ensure that the flight crew is advised of

the potential hazard associated with

increasing the flap settings when ice

contaminated tailplane stall (ICTS)

conditions are present, and the procedures

necessary to address it, accomplish the

following:

(a) Within 30 days after the effective date

of this AD, revise the Limitations Section of

the FAA-approved Airplane Flight Manual

(AFM) to include the following procedures,

which will limit the flap settings during

certain icing conditions and air temperatures.

This may be accomplished by inserting a

copy of this AD in the AFM.

‘‘FLAP LIMITATION IN ICING CONDITIONS

Flap selection is limited to a maximum of

30 degrees after icing conditions have been

encountered; or when icing conditions are

anticipated during approach and landing; or

when the outside air temperature is +5

degrees Celsius or below and any visible

moisture is present.’’

(b) 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 (ACO),

FAA, Transport Airplane Directorate.

Operators shall submit their requests through

an appropriate FAA Principal Maintenance

Inspector, who may add comments and then

send it to the Manager, Los Angeles ACO.

Note: Information concerning the existence

of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Los Angeles ACO.

(c) 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 airplane to

a location where the requirements of this AD

can be accomplished.

(d) This amendment becomes effective on

February 28, 1996.

Issued in Renton, Washington, on January

23, 1996.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 96–1517 Filed 1–26–96; 8:45 am]

BILLING CODE 4910–13–U

14 CFR Part 39

[Docket No. 95–CE–88–AD; Amendment 39–

9500; AD 95–24–10]

Airworthiness Directives; Michelin

Aircraft Tire Corporation Part Number

028–520–1 (22x5.75–12/10PR) Tires

Installed on the Main Landing Gear of

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule; request for

comments.

SUMMARY: This document publishes in

the Federal Register an amendment

adopting Airworthiness Directive (AD)

95–24–10, which was sent previously to

all known U.S. owners and operators of

airplanes with a Michelin Aircraft Tire

Corporation part number (P/N) 028–

520–1 (22x5.75–12/10PR) tire installed

on the main landing gear. This AD

requires replacing any of the affected

tires with an FAA-approved tire. Two

reports of failure (rupture) of the main

landing gear tire during landing

operations on Cessna Citation VII

airplanes prompted priority letter AD

95–24–10. The actions specified by this

AD are intended to prevent loss of

control of the airplane during landing

operations because of failure of a P/N

028–520–1 (22x5.75–12/10PR) tire.

DATES: Effective February 21, 1996, to

all persons except those to whom it was

made immediately effective by priority

letter AD 95–24–10, issued November

21, 1995, which contained the

requirements of this amendment.

Comments for inclusion in the Rules

Docket must be received on or before

April 30, 1996.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Central Region,

Office of the Assistant Chief Counsel,

Attention: Rules Docket 95–CE–88–AD,

Room 1558, 601 E. 12th Street, Kansas

City, Missouri 64106.

Information that relates to this AD

may be examined at the Rules Docket at

the address above, or at the Office of the

Federal Register, 800 North Capitol

Street NW., 7th Floor, suite 700,

Washington, DC.

FOR FURTHER INFORMATION CONTACT: Ms.

Denise Bosonetto, Aerospace Engineer,