Airworthiness Directives; Fokker Model F28 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-174-AD; Amendment 39-9087; AD 94-25-03]

Airworthiness Directives; Fokker Model F28 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that

is applicable to all Fokker Model F28 series airplanes. This action

requires a revision to the Airplane Flight Manual that prohibits

takeoff in certain icing conditions unless either a tactile inspection

is performed or specific takeoff procedures are followed. This

amendment is prompted by several accidents in which Fokker Model F28

series airplanes lost aerodynamic lift when attempting takeoff with ice

contamination on their wings. The actions specified in this AD are

intended to prevent degradation of aerodynamic lift during takeoff when

icing conditions exist.

DATES: Effective December 21, 1994.

Comments for inclusion in the Rules Docket must be received on or

before February 6, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 94-NM-174-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

Information concerning this amendment may be examined at the FAA,

Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

FOR FURTHER INFORMATION CONTACT: Timothy J. Dulin, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2141; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: The FAA has received reports of at least

three accidents involving Fokker Model F28 series airplanes in which

the probable cause has been attributed to wing ice contamination prior

to takeoff. The FAA has determined that airplanes with wings that do

not have leading edge high lift devices, such as the Fokker Model F28

series airplanes, are particularly susceptible to loss of lift when

attempting to take off with minimal amounts of ice accumulation

(contamination) on the wings. Further, the FAA finds that airplanes

with this configuration account for a disproportionate number of the

total number of accidents attributable to wing ice contamination. In

light of this, the FAA has determined that, for airplanes with this

configuration, an extra degree of protection is necessary beyond

reliance solely on operation in accordance with the current

requirements specified in section 121.629 (``Operation in icing

conditions''), amendment 121-231, of the Federal Aviation Regulations

(14 CFR 121.629).

The FAA has determined that one acceptable (interim) method of

addressing icing problems associated with airplanes having this

configuration is a physical (tactile) and visual check of the leading

edge and upper wing surfaces to verify that there is no accumulation of

ice, frost, and snow prior to takeoff. The FAA previously issued AD 93-

11-01 [amendment 39-8593 (58 FR 33898, June 22, 1993)], which requires

such a tactile check of McDonnell Douglas Model DC-9-10 series

airplanes; those airplanes, like the Model F28, do not have leading

edge high lift devices. The intent of checks such as these is to

prevent takeoff with wing ice contamination, which can result in the

degradation of wing lift, and can result in the airplane stalling at

lower than normal angles-of-attack during takeoff.

Additionally, the Rijksluchtvaartdienst (RLD), which is the

airworthiness authority for the Netherlands, issued Netherlands

Airworthiness Directive (BLA) 93-167/2 (A), dated April 29, 1994,

applicable to Fokker Model F28 series airplanes operating in the

Netherlands. This BLA describes an ``alternative'' takeoff procedure

that can be followed to improve stall margins whenever icing conditions

exist. [This ``alternative'' takeoff procedure was developed in

response to the U.S. National Transportation Safety Board's (NTSB)

Safety Recommendation A-93-023.] The ``alternative'' takeoff procedure

requires the availability of 120 percent of the minimum takeoff

distance for the actual gross weight. Additionally, the 20 percent

increase in takeoff distance must be accounted for in the obstacle

clearance analysis. The BLA specifies that the ``alternative'' takeoff

procedure is an optional procedure that is available for use when

sufficient runway length and obstacle clearance margin are available.

The FAA has reviewed and approved this ``alternative'' takeoff

procedure as an interim measure that will acceptably address the

problems associated with takeoff and operation of Model F28 series

airplanes in icing conditions. Although the RLD has classified the

procedure as optional, the FAA has determined that it must be mandated

as one method to ensure that these airplanes have adequate lift to

effect a safe takeoff when icing conditions exist.

As indicated previously, the FAA has determined that the

accomplishment of these types of additional actions is necessary in

order to provide an extra degree of protection for Model F28 series

airplanes, beyond that provided by the current operating requirements

specified in part 121 of the FAR.

Fokker has advised the FAA that it is currently developing a

modification to the thermal anti-ice system on all Fokker Model F28

series airplanes. This modification would allow the thermal anti-ice

system to operate on the ground, which would prevent reformation of ice

on the wing leading edges after ground equipment has been used to

properly de-ice/anti-ice the airplane, and would minimize the effect of

undetected ice/frost/snow contamination. Fokker has indicated that this

proposed modification will be similar to the one required by AD 93-11-

01 for McDonnell Douglas DC-9-10 series airplanes. (That AD requires a

modification of the wing leading edge bleed air anti-ice system on so

that it can operate on the ground to prevent the reformation of ice

after de-icing procedures have been accomplished.) However, because

this proposed modification for Model F28 series airplanes currently is

under development, any associated modification instructions or required

parts are not available at this time.

This airplane model is manufactured in the Netherlands and is type

certificated for operation in the United States under the provisions of

section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and

the applicable bilateral airworthiness agreement. The FAA has

determined that AD action is necessary for products of this type design

that are certificated for operation in the United States.

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design registered

in the United States, this AD is being issued to prevent degradation of

the aerodynamic lift during takeoff due to wing ice contamination,

which could result in the airplane stalling at lower than normal

angles-of-attack during takeoff. This AD requires a revision to the

Limitations Section of the FAA-approved Airplane Flight Manual (AFM),

which requires that, whenever icing conditions exist, one of the

following actions must be accomplished:

1. A physical (tactile) check to detect ice, frost, and snow

accumulation on the leading edge and upper wing surfaces must be

performed prior to takeoff. (This check is similar to that required by

AD 93-11-01 for McDonnell Douglas Model DC-9-10 series airplanes). Or

2. The airplane must be operated in accordance with the

``alternative'' takeoff procedure developed by Fokker that improves

stall margins. Use of the ``alternative'' takeoff procedure would

require weight to be off loaded, if necessary, to meet the revised

takeoff distance and obstacle clearance requirements. -

This AD also provides for the termination of these requirements if

the airplane's thermal anti-ice system is modified and operated in

accordance with a method approved by the FAA. -

This is considered to be interim action. As stated previously,

Fokker currently is developing a design modification that will

positively address the unsafe condition that is the subject of this

rulemaking action. Once this modification, as well as its associated

operating procedures and an implementation schedule, are developed,

approved, and available, the FAA may consider additional rulemaking

action. -

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

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 shall 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, both before and after the closing date for comments, 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 comments

submitted in response to this rule must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 94-NM-174-AD.'' The postcard will be date stamped and

returned to the commenter. -

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. -

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

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. 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 adding the following new

airworthiness directive:

94-25-03 Fokker: Amendment 39-9087. Docket 94-NM-174-AD.

-Applicability: All Model F28 series airplanes (all Marks and all

serial numbers), certificated in any category. -

Compliance: Required as indicated, unless accomplished previously.

-

To prevent degradation of aerodynamic lift during takeoff when

icing conditions exist, accomplish the following: -

(a) Within 10 days after the effective date of this AD, incorporate

the following into the Limitations Section of the FAA-approved Airplane

Flight Manual (AFM). This may be accomplished by inserting a copy of

this AD in the AFM.

``Wing De-Icing/Anti-Icing Prior To Takeoff

CAUTION

The Model F28 series airplane has a wing design with no leading

edge high lift devices, such as slats. Wings without leading edge high

lift devices are particularly susceptible to loss of lift due to wing

icing. Minute amounts of ice or other contamination (equivalent to

medium grit sandpaper) on the leading edges or upper wing surfaces can

cause significant reduction in the stall angle-of-attack. This can

increase stall speed up to 30 knots. The increased stall speed can be

well above the stall warning (stick shaker) activation speed.

Takeoff shall not be attempted unless the pilot-in-command has

ensured that the aircraft surfaces are free of ice, frost, and snow

accumulation, as required by sections 91.527 and 121.629 of the Federal

Aviation Regulations (FAR).

In addition, takeoff shall not be attempted when the Outside Air

Temperature (OAT) is below 6 degrees C (Centigrade) [42 degrees F

(Fahrenheit)]; and either the difference between the dew point

temperature and OAT is less than 3 degrees C (5 degrees F), or visible

moisture (rain, drizzle, sleet, snow, fog, etc.) is present, unless the

operator complies with either OPTION 1 or OPTION 2, below:

OPTION 1

The leading edge and upper wing surfaces have been physically

checked for ice/frost/snow and the flight crew verifies that a visual

check and a physical (hands-on) check of the leading edge and upper

wing surfaces has been accomplished and that the wing is clear of ice/

frost/snow accumulation.

OR

OPTION 2

The following takeoff procedure is used:

WARNING:

The following technique cannot be used unless the pilot-in-command

has ensured that the aircraft surfaces are free of ice, frost, and

snow, as required by sections 91.527 and 121.629 of the FAR.

(All Marks, except Mark 0100 and Mark 0070) When using

flight director for takeoff, select HDG mode and 10 degrees pitch

attitude.

Select the largest flap setting that is permissible for

the takeoff weight/altitude/temperature conditions.

(All Marks, except Mark 0100 and Mark 0070) Use rated

takeoff thrust.

(Mark 0100 and Mark 0070) Use takeoff/go-around (TOGA)

thrust.

Do not use FLEXIBLE thrust.

At VR rotate slowly (less than 3 degrees per second)

to 10 degrees pitch attitude.

When positively climbing, select gear UP.

DO NOT EXCEED 10 DEGREES PITCH UNTIL AIRSPEED IS ABOVE

V2+20 KTS.

When above V2+20 KTS, slowly increase the pitch

attitude, keeping the speed above V2+20 KTS.

Retract the flaps at or above VFR + 20 KTS.

Notes to Option 2

1. The available field length must be greater than or equal to 120

percent of the takeoff distance required by regulation for the actual

gross weight. Also, the 20 percent increase in takeoff distance must be

accounted for in the obstacle clearance analysis. WEIGHT MUST BE OFF-

LOADED, IF NECESSARY, TO MEET THESE CONDITIONS.

2. (Mark 0100 and Mark 0070) Do not follow the Flight Director

pitch command during rotation for takeoff and initial climb, as this

will result in exceeding the recommended maximum pitch angle of 10

degrees before reaching the speed of V2+20 KTS.

3. (Mark 0100 and Mark 0070) Do not engage the auto-pilot until

leaving the Automated Flight Control and Augmentation System (AFCAS)

takeoff (TO) mode.

4. For the case of an engine failure, refer to the applicable

procedure in Section 4.17.01 SINGLE ENGINE OPERATION of the F28 Mark

0100 (Fokker 100) and F28 Mark 0070 (Fokker 70) AFM, or Section 1.7.4

OPERATION UNDER ABNORMAL CONDITIONS of the F28 FHB, as applicable.

5. During takeoff, the first indication of wing contamination will

probably be airframe buffet when the pitch angle is increased above 10

degrees, followed by wing drop and insufficient climb rate. DO NOT

EXCEED 10 DEGREES PITCH UNTIL AIRSPEED IS ABOVE V2+20 KTS.''

Note 1: If an operator elects to implement in its fleet only one

of the two OPTIONS specified in this paragraph, the other OPTION

does not have to be included in the Limitations Section of the AFM.

However, the OPTION that is implemented must be incorporated in the

AFM verbatim as it appears in this paragraph.

-(b) Modification of the thermal anti-ice system so that it can be

operated on the ground, in accordance with a method approved by the

Manager, Standardization Branch, ANM-113, FAA, Transport Airplane

Directorate, constitutes terminating action for the requirements of

this AD.

Note 2: Incorporation of the leading edge thermal anti-ice

modification and associated operating instructions does not relieve

the requirement that aircraft surfaces are free of ice, frost, and

snow accumulation as required by sections 91.527 and 121.629 of the

Federal Aviation Regulations (14 CFR 91.527 and 121.629).

-(c) 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, Standardization Branch, ANM-113. Operators

shall submit their requests through an appropriate FAA Principal

Operations Inspector, who may add comments and then send it to the

Manager, Standardization Branch, ANM-113.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

-(d) 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. -

(e) This amendment becomes effective on December 21, 1994.

Issued in Renton, Washington, on November 30, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-29921 Filed 12-5-94; 8:45 am]

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