[Federal Register Volume 65, Number 57 (Thursday, March 23, 2000)]
[Rules and Regulations]
[Pages 15537-15540]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-7224]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-CE-49-AD; Amendment 39-11646; AD 2000-06-06]
RIN 2120-AA64


Airworthiness Directives; The New Piper Aircraft, Inc. PA-31 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This document adopts a new airworthiness directive (AD) that 
applies to all The New Piper Aircraft, Inc. PA-31 series airplanes that 
are equipped with pneumatic deicing boots. This AD requires revising 
the Airplane Flight Manual (AFM) to include requirements for activation 
of the airframe pneumatic deicing boots. This AD is the result of 
reports of in-flight incidents and an accident that occurred in icing 
conditions where the airframe pneumatic deicing boots were not 
activated. The actions specified by this AD are intended to assure that 
flightcrews activate the pneumatic wing and tail deicing boots at the 
first signs of ice accumulation. This action will prevent reduced 
controllability of the aircraft due to adverse aerodynamic effects of 
ice adhering to the airplane prior to the first deicing cycle.

EFFECTIVE DATE: May 5, 2000.

ADDRESSES: You may examine information related to this AD at the 
Federal Aviation Administration (FAA), Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 99-CE-49-AD, 901 Locust, 
Room 506, Kansas City, Missouri 64106.

FOR FURTHER INFORMATION CONTACT: Mr. John P. Dow, Sr., Aerospace 
Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 506, Kansas 
City, Missouri 64106; telephone: (816) 329-4121; facsimile: (816) 329-
4090.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    What caused this AD? This AD is the result of reports of in-flight 
incidents and an accident that occurred in icing conditions where the 
airframe pneumatic deicing boots were not activated.
    What is the potential impact if the FAA took no action? The 
information necessary to activate the pneumatic wing and tail deicing 
boots at the first signs of ice accumulation is critical for flight in 
icing conditions. If we did not take action to include this 
information, flight crews could experience reduced controllability of 
the aircraft due to adverse aerodynamic effects of ice adhering to the 
airplane prior to the first deicing cycle.
    Has the FAA taken any action to this point? Yes. We issued a 
proposal to amend part 39 of the Federal Aviation Regulations (14 CFR 
part 39) to include an AD that would apply all Piper PA-31 series 
airplanes that are equipped with pneumatic deicing boots. This proposal 
was published in the Federal Register as a notice of proposed 
rulemaking (NPRM) on October 12, 1999 (64 FR 55204). The NPRM proposed 
to require revising the Limitations Section of the AFM to include 
requirements for activating the pneumatic deicing boots at the first 
indication of ice accumulation on the airplane.
    Was the public invited to comment? Yes. Interested persons were 
afforded an opportunity to participate in the making of this amendment. 
The following paragraphs present the comments received on the NPRM. 
Also included is the FAA's response to each comment, including any 
changes incorporated into the final rule based on the comments.

Comment Issue No. 1: Coordinate With Original Equipment 
Manufacturer

    What is the Commenter's Concern? One commenter states that the FAA 
should coordinate with the original equipment manufacturer before 
issuing the AD.
    What is the FAA's Response to the Concern? We concur. The FAA 
coordinates and will continue to coordinate with the manufacturer of 
any affected airplanes before issuing an AD.
    Is it Necessary to Change the AD? No.

Comment Issue No. 2: Provide the Criteria for Determining 
Acceptable Stall Warning Margins

    What is the Commenter's Concern? One commenter requests that the 
FAA provide the criteria for determining whether an airplane has an 
acceptable stall warning margin. The commenter references recent NPRM 
AD withdrawals in the FAA's Transport Airplane Directorate.
    What is the FAA's Response to the Concern? We cannot provide such 
information because no regulatory basis exists for determining or 
applying a mandatory stall margin with contamination. We can review 
manufacturer-provided data to determine what testing was conducted, and 
then determine the effects of ice

[[Page 15538]]

accretion on the stall angle and the handling characteristics in the 
roll axis. This would include reviewing the service history of each 
airplane. With all of this information, we could determine whether the 
stall warning margin was acceptable and if the AD action could be 
withdrawn.
    Such was the case with the NPRM withdrawals in the FAA's Transport 
Airplane Directorate. The airplanes affected were Cessna Models 500, 
501, 550, 551, and 560 series airplanes, and British Aerospace 
Jetstream Model 4101 airplanes. You may find the specific justification 
for each of these withdrawals in the Federal Register through the 
following citations:

    --For the Cessna airplanes: 64 FR 62995, November 18, 1999; and
    --For the Jetstream airplanes: 64 FR 62990, November 18, 1999.

    No specific information was submitted for the Piper PA-31 series 
airplanes.
    Is it Necessary to Change the AD? No.

Comment Issue No. 3: Define the Term ``Modern'' Pneumatic Boot 
Systems

    What is the Commenters' Concern? Two commenters request explanation 
on the use of the term ``modern'' in a similar AD action that the FAA's 
Transport Airplane Directorate initiated.
    What is the FAA's Response to the Concern? The FAA's Transport 
Airplane Directorate addressed the issue of ``modern'' versus ``older'' 
pneumatic boot systems in a recent AD action. That information, in its 
entirety, follows:

    ``Several commenters request that the difference between the 
``older'' and ``modern'' boot systems be explained. These commenters 
express concern that although both systems are addressed in the 
proposal, there may not be a sound technical reason to apply the 
requirements of the proposal to both types of boot systems.
    The FAA acknowledges that definitions of ``older'' and 
``modern'' pneumatic boot systems should be provided. Therefore, for 
the purposes of this AD, ``modern'' pneumatic boot systems may be 
characterized by short segmented, small diameter tubes, which are 
operated at relatively high pressures [18-23 pounds per square inch 
(psi)] by excess bleed air that is provided by turbine engines. 
``Older'' pneumatic boot systems may be characterized by long, 
uninterrupted, large diameter tubes, which were operated at low 
pressures by engine driven pneumatic pumps whose pressure varied 
with engine revolutions per minute (rpm). This low pressure coupled 
with long and large diameter tubes caused early deice systems to 
have very lengthy inflation and deflation cycles and dwell times. 
(Dwell time is the period of time that the boot remains fully 
expanded following the completion of the inflation cycle until the 
beginning of the deflation cycle.)''

    Is it Necessary to Change the AD? No.

Comment Issue No. 4: No Justification for This AD

    What is the Commenter's Concerns? One commenter cites reasons why 
the proposed AD is not justified. These consist of the following:
    1. The original equipment manufacturer installs pneumatic airframe 
components based on ice impingement and accretion analysis and best 
engineering judgement. The pneumatic boot manufacturer performed ice 
tunnel testing of deicers representative of those installed on PA-31 
series airplanes and has issued operating instructions for its 
components. The original equipment manufacturer performs flight test in 
natural icing conditions where the operating instructions on specific 
installations (with unique geometry, speeds, etc.) without flight 
testing to substantiate those procedures. This would seem to violate 
the current FAA rationale for testing for flight into known icing; and
    2. There is no data in the NPRM that pertains to the Piper PA-31 
series airplanes to justify AD action.
    What is the FAA's Response to the Concerns? We do not concur that 
the AD is not justified. Our response to each concern is as follows:
    1. While the information the commenter presents is accurate, the 
intent of this AD is to mandate when the pneumatic deicing boots should 
be activated. As the commenter discusses, the original equipment 
manufacturer tests the components and issues operating instructions for 
its components. The type certificate holder works with the original 
equipment manufacturer to assure that the operating instructions adhere 
to the original design configuration of the affected airplanes. This AD 
only provides the information for and mandates when the pneumatic 
deicing system is activated; and
    2. The AD is based upon reports of in-flight incidents and an 
accident that occurred in icing conditions where the airframe pneumatic 
deicing boots were not activated. Although Piper PA-31 series airplanes 
were not among those in the reports, these airplanes incorporate a 
similar type design. Therefore, the unsafe condition could exist on the 
Piper PA-31 series airplanes and AD action is appropriate.
    Is it Necessary to Change the AD? No.

Comment Issue No. 5: Pneumatic Deicing Boot Manufacturer Should 
Issue Operating Instructions

    What is the Commenter's Concern? One commenter states that the 
deice boot manufacturer should issue any change in the operating 
instructions of the pneumatic deicing system.
    What is the FAA's Response to the Concern? We do not concur that 
the deice boot manufacturer is responsible for developing the operating 
instructions for a specific airplane. The original equipment 
manufacturer or airplane manufacturer should issue changes in the 
operating instructions of the pneumatic deicing system. As discussed in 
the previous comment, the original equipment manufacturer tests the 
components and issues operating instructions for its components. The 
type certificate holder works with the original equipment manufacturer 
to assure that the operating instructions adhere to the original design 
configuration of the affected airplanes. This AD only provides the 
information for and mandates when the pneumatic deicing system is 
activated.
    Is it Necessary to Change the AD? No.

Comment Issue No. 6: The AD Should Also Apply to Other Airplane 
Models

    What is the Commenter's Concern? One commenter suggests that the AD 
apply to other Piper airplanes that are of a similar type design. The 
commenter states that the AD should also apply to the following 
airplane models: PA-31T, PA-31T1, PA-31T2, PA-31T3, PA-42, PA-42-720, 
PA-42-720R, and PA-42-1000.
    What is the FAA's Response to the Concern? We concur that all of 
these airplane models are of a similar type design and AD action should 
be taken to address the safety issues. However, the Models PA-31T1, PA-
31T2, and PA-31T3 airplanes were included in the NPRM. Rather than hold 
up the AD, we will initiate a separate AD action (NPRM) for the Piper 
Models PA-42, PA-42-720, PA-42-720R, and PA-42-1000 airplanes.
    Is it Necessary to Change the AD? No. However, as discussed above, 
we will initiate a separate AD action (NPRM) for the Piper Models PA-
42, PA-42-720, PA-42-720R, and PA-42-1000 airplanes.

Comment Issue No. 7: Limit the AFM Change to Approach and Hold 
Phases of Flight

    What is the Commenter's Concern? One commenter requests that the 
FAA limit the AFM change of operating the boots at the first sign of 
ice accretion to

[[Page 15539]]

the approach and hold phases of flight. This commenter references the 
work that the Ice Protection Harmonization Working Group (IPHWP) is 
currently doing. The commenter states that the IPHWP believes that the 
only phases of flight that demonstrate a safety concern are holding 
patterns and various approach segments. Since these operations occur at 
lower speeds, ice accumulating on the wing and tail surfaces could 
cause instability.
    What is the FAA's Response to the Concern? We do not concur to 
limiting the AFM change to the holding and approach phases of flight. 
We acknowledge that the IPHWG is working on a proposed operations rule. 
The IPHWG continues to work on this proposed rule and has not reached 
technical agreement. We have records of in-flight roll upsets in icing 
during the climb and cruise phases of flight on small airplanes that 
are of a similar type design to the Piper PA-31 series airplanes.
    We concur that the ice protection system should not be operated at 
times when no ice is accreting. We have changed the description of the 
atmospheric conditions that the deicing boots must be operated from 
``icing conditions'' to ``known or observed/detected icing that the 
flight crew visually observed on the aircraft or was identified by the 
on-board sensors.'' Is it Necessary to Change the AD? Yes. We have made 
the change described above in the final rule.

Comment Issue No. 8: Require Action To Reduce Adhesion 
Characteristics

    What is the Commenter's Concern? In response to previous NPRM's on 
this subject, a commenter has requested that the FAA mandate actions to 
minimize or reduce the ice adhesion characteristics of boot material. 
The commenter stated that one reason flightcrews see large amounts of 
residual ice is because residual ice sticks to the boot surface as the 
boot ages. This may increase if the adhesion qualities of the boot 
material are not maintained. The commenter suggested the use of certain 
compounds, such as ICEX\TM\ (an ice-phobic chemical spray), to reduce 
ice adhesion.
    What is the FAA's Response to the Concern? We concur that materials 
such as ICEXTM could reduce ice adhesion. However, factors 
such as normal wear and tear, patching, and oxidation of boot material, 
prevent us from establishing an effective level of application or 
adequate intervals of application. We included a Note in previous AD's 
to recommend regular treatment of deicing boots with use of approved 
ice release agents. This is in addition to the required actions.
    Is it Necessary to Change the AD? No. However, as discussed above, 
the FAA included a Note in previous AD's to recommend regular treatment 
of deicing boots with use of approved ice release agents. We are 
including this Note in this AD also.

The FAA's Determination

    What is the FAA's final determination on this issue? After careful 
review of all available information related to the subject presented 
above, we have determined that air safety and the public interest 
require the adoption of the rule as proposed except for the following:

--The change in the description of the atmospheric conditions that the 
deicing boots must be operated;
--The addition of the NOTE to recommend regular treatment of deicing 
boots with use of approved ice release agents; and
--Minor editorial corrections.
    How does the change, addition, and corrections affect the AD? We 
have determined that the change, addition, and minor corrections will 
not change the meaning of the AD and will not add any additional burden 
upon the public than was already proposed.

Cost Impact

    How many airplanes does this AD impact? We estimate that 2,314 
airplanes in the U.S. registry will be affected.
    What is the cost impact of the affected airplanes on the U.S. 
Register? There is no dollar cost impact. We estimate that to 
accomplish the AFM revision it will take you less than 1 workhour. You 
can accomplish this action if you hold at least a private pilot 
certificate as authorized by Sec. 43.7 of the Federal Aviation 
Regulations (14 CFR 43.7). You must make an entry into the aircraft 
records that shows compliance with this AD, in accordance with 
Sec. 43.9 of the Federal Aviation Regulations (14 CFR 43.9). The only 
cost impact of this AD is the time it will take you to insert the 
information into the AFM.

Regulatory Impact

    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.
    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 copy of the final 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 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 
(AD) to read as follows:


2000-06-06  The New Piper Aircraft, Inc.: Amendment 39-11646; Docket 
No. 99-CE-49-AD.

    (a) What airplanes are affected by this AD? PA-31, PA-31-300, 
PA-31-325, PA-31-350, PA-31P, PA-31T, PA-31T1, PA-31T2, PA-31T3, and 
PA-31P-350 airplanes, all serial numbers, that are:
    (1) equipped with pneumatic deicing boots; and
    (2) certificated in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above airplanes on the U.S. Register. The AD does not 
apply to your airplane if it is not equipped with pneumatic de-icing 
boots.
    (c) What problem does this AD address? The information necessary 
to activate the pneumatic wing and tail deicing boots at the first 
signs of ice accumulation is critical for flight in icing 
conditions. If we did not take action to include this information, 
flight crews could experience reduced controllability of the 
aircraft due to adverse aerodynamic effects of ice adhering to the 
airplane prior to the first deicing cycle.
    (d) What must I do to address this problem? To address this 
problem, you must revise the Limitations Section of the FAA-approved 
Airplane Flight Manual (AFM) to

[[Page 15540]]

include the following requirements for activation of the ice 
protection systems. You must accomplish this action within the next 
10 calendar days after the effective date of this AD, unless already 
accomplished. You may insert a copy of this AD in the AFM to 
accomplish this action:
    `` Except for certain phases of flight where the AFM 
specifies that deicing boots should not be used (e.g., take-off, 
final approach, and landing), compliance with the following is 
required.
     Wing and Tail Leading Edge Pneumatic
    Deicing Boot System, if installed, must be activated:
    --At the first sign of ice formation anywhere on the aircraft, 
or upon annunciation from an ice detector system, whichever occurs 
first; and
    --The system must either be continued to be operated in the 
automatic cycling mode, if available; or the system must be manually 
cycled as needed to minimize the ice accretions on the airframe.
     The wing and tail leading edge pneumatic deicing boot 
system may be deactivated only after:
    --leaving known or observed/detected icing that the flight crew 
has visually observed on the aircraft or was identified by the on-
board sensors; and
    --after the airplane is determined to be clear of ice.''

    Note: The FAA recommends periodic treatment of deicing boots 
with approved ice release agents, such as ICEX\TM\, in accordance 
with the manufacturer's application instructions.

    (e) Can the pilot accomplish the action? Yes. Anyone who holds 
at least a private pilot certificate, as authorized by section 43.7 
of the Federal Aviation Regulations (14 CFR 43.7), may incorporate 
the AFM revisions required by this AD. You must make an entry into 
the aircraft records that shows compliance with this AD, in 
accordance with section 43.9 of the Federal Aviation Regulations (14 
CFR 43.9).
    (f) Can I comply with this AD in any other way? Yes.
    (1) You may use an alternative method of compliance or adjust 
the compliance time if:
    (i) Your alternative method of compliance provides an equivalent 
level of safety; and
    (ii) The Manager, Small Airplane Directorate, approves your 
alternative. Submit your request through an FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager.
    (2) This AD applies to each airplane 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 airplanes 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)(1) 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 you have not eliminated the unsafe 
condition, specific actions you propose to address it.
    (g) Where can I get information about any already-approved 
alternative methods of compliance? Contact the Small Airplane 
Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; 
telephone: (816) 329-4121; facsimile: (816) 329-4091.
    (h) What if I need to fly the airplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your airplane to a location where 
you can accomplish the requirements of this AD.
    (i) When does this amendment become effective? This amendment 
becomes effective on May 5, 2000.


    Issued in Kansas City, Missouri, on March 17, 2000.
Carolanne L. Cabrini,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-7224 Filed 3-22-00; 8:45 am]
BILLING CODE 4910-13-P