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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-CE-36-AD; Amendment 39-11762; AD 2000-11-14] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule. 

# SUMMARY:

This document adopts a new airworthiness directive (AD) that applies to all Pilatus Aircraft Ltd. (Pilatus) Models PC-12 and PC-12/45 airplanes that are equipped with pneumatic deicing boots. This AD requires you to revise 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 (on airplanes other than the affected Pilatus airplanes) that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The Pilatus Models PC-12 and PC-12/45 airplanes have a similar type design (as it relates to airframe pneumatic ice boots) to the incident and accident airplanes. 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:

July 17, 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-36-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 (on airplanes other than the affected Pilatus airplanes) that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The Pilatus Models PC-12 and PC-12/45 airplanes have a similar type design (as it relates to airframe pneumatic ice boots) to the incident and accident airplanes. 

### What Is the Potential Impact If 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 FAA Taken Any Action to This Point? 

                    We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all Pilatus Models PC-12 and PC-12/45 airplanes that are equipped with pneumatic deicing boots. This proposal published in the                     **Federal Register**                     as a notice of proposed rulemaking (NPRM) on October 8, 1999 (64 FR 54833). The NPRM proposed to require revising the Limitations Section of the AFM to include requirements for activation of pneumatic deicing boots at the first indication of ice accumulation on the airplane.                 

### Was the Public Invited To Comment? 

The FAA invited interested persons to participate in the making of this amendment. Following is a summary of the two comments received with FAA's response. 

## Comment Issue No. 1: Allow the Use of Recent Airplane Flight Manual (AFM) Additions 

### What Is the Commenter's Concern? 

Pilatus requests that FAA allow the operators of the affected airplanes to use as an alternative method of compliance the most recent information for Section 2, Limitations, of the Pilatus PC12 Airplane Flight Manual (AFM). This information is included in Report No.: 01973-001, page 2-12, Revision 9: September 1, 1999, and includes the following language:

The wing and tail leading edge pneumatic deicing boot system must be activated at the first sign of ice formation anywhere on the aircraft, or upon annunciation from an ice detector system (if installed), whichever occurs first. 

The wing and tail leading edge pneumatic deicing boot system may be deactivated only after leaving icing conditions and after the aircraft is determined to be clear of ice.

### What Is FAA's Response to the Concern? 

We have determined that inserting this report into the Section 2, Limitations, of the Pilatus PC12 AFM provides an equivalent level of safety to the actions included in the NPRM. Therefore, we are changing the AD to include the option of incorporating into the AFM the information proposed in the NPRM or Report No.: 01973-001, page 2-12, Revision 9: September 1, 1999.

## Comment Issue No. 2: Information is Already Included in the Normal Procedures Section of the AFM 

### What Are the Commenter's Concerns? 

The Federal Office for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, believes that the intent of this AD is already covered in the Pilatus PC12 AFM. The FOCA's concerns are as follows: 

1. The appropriate time to activate the pneumatic deice boots on the affected Pilatus airplanes is prior to entry into icing conditions, and until the airfoils are free of ice after exiting icing conditions. This information is included in Section 4.10 (Normal Procedures) of the PC12 AFM; 

                    2. These instructions are not necessary in the Limitations Section of the AFM. The Limitations Section should only include limitations relating to speeds, environment (temperatures),                           ( print page 35271)                        or system functions (time limits or configurations). Guidance for this is in FAA Advisory Circular (AC) 25.1419-1, dated August 18, 1999. Paragraph 12(b)(2) of this AC identifies the Procedures Section as the proper place for information “. . . when the ice protection system should be activated.”                

The FOCA requests FAA withdraw the NPRM. 

### What Is FAA's Response to the Concerns? 

We concur that the information is currently in the Normal Procedures section of the Pilatus PC12 AFM and that previous guidance (advisory circulars) provides information for putting this information in such a section. However, section 91.9 of the Federal Aviation Regulations (14 CFR 91.9) only mandates the operating limitations (Limitations Section): “no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual.” 

Based upon the importance of operating the deice boots at the appropriate time, we determined that the information is mandatory. The only method FAA has of changing the Limitations Section of an AFM is through AD action, provided an unsafe condition is demonstrated. 

Therefore, we do not concur that the NPRM should be withdrawn. We are not changing the AD as a result of this comment. 

## The FAA's Determination 

### What Is 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: 

—Including the option of incorporating Report No.: 01973-001, page 2-12, Revision 9: September 1, 1999, into Section 2, Limitations, of the Pilatus PC12 AFM; and 

—Minor editorial corrections. 

### How Does Including This Option and the Minor Editorial Corrections Affect the AD? 

We have determined that including the AFM option and the 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 this AD affects 100 airplanes in the U.S. registry. 

### What Is the Cost Impact of the Affected Airplanes on the U.S. Register?

There is no dollar cost impact. We estimate 1 workhour for you to insert the AFM revision. You can accomplish this action if you hold at least a private pilot certificate as authorized by section 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 section 43.9 of the Federal Aviation Regulations (14 CFR 43.9). Therefore, 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 in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## Adoption of the Amendment 

Accordingly, under 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 

2. FAA amends Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: 

**2000-11-14 PILATUS AIRCRAFT LTD.**                            : Amendment 39-11762; Docket No. 99-CE-36-AD.                         

                            (a)                             *What airplanes are affected by this AD?*                             Models PC-12 and PC-12/45 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 FAA-approved Airplane Flight Manual (AFM) to include the following requirements for activation of the ice protection systems. You must accomplish this action within the next 10 calendar days after July 17, 2000 (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)                             *Have I accomplished the intent of this AD if I have incorporated the latest Pilatus PC12 AFM report into Section 2, Limitations?*      ( print page 35272)                                As an alternative method of compliance to the actions required by paragraphs (a), (a)(1), and (a)(2) of this AD, you may incorporate Report No.: 01973-001, page 2-12, Revision 9: September 1, 1999, into Section 2, Limitations, of the Pilatus PC12 AFM.                         

                            (f)                             *Can the pilot accomplish the action?*                             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, showing compliance with this AD, in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9).                         

                            (g)                             *Can I comply with this AD in any other way?*                             You may use an alternative method of compliance or adjust the compliance time if:                         

(1) Your alternative method of compliance provides an equivalent level of safety; and 

(2) 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.

# Note:

This AD applies to each airplane identified in paragraph (a) of this AD, 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 (g) 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.

                            (h)                             *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.                         

                            (i)                             *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.                         

                            (j)                             *When does this amendment become effective?*                             This amendment becomes effective on July 17, 2000.                        

Issued in Kansas City, Missouri, on May 24, 2000.

James E. Jackson, 

Acting Manager, Small Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-13874 Filed 6-1-00; 8:45 am] 

BILLING CODE 4910-13-U