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Small Airplane Directorate
601 E. 12th Street
Kansas City, MO 64106


JAN 24 1990

 

Messrs. Norman L. Horton and Jerry L. Wells
Aviation Safety and Management Consultants
4582 Old Stage Road
Central Point, Oregon 97502

 

Gentlemen:

 

Administrator Busey has asked me to respond to your letter of December 21, 1989, concerning fuel contamination in Piper PA-23 airplanes. While your letter fully describes the action you have taken to alleviate the problem, it implies that the Federal Aviation Administration (FAA) has ignored your suggestions for corrective action and has made little effort to correct the problem.

 

In response to service reports and inquiries from your organization, the FAA established a team in 1987, to conduct an independent evaluation of the Piper PA-23 fuel system, with respect to water contamination and drain provisions. Mr. Horton was invited to participate, but was unable to do so because of a previous commitment. As a result of the investigation, the FAA issued Airworthiness Directive 88-21-07, copy enclosed, which requires repetitive inspections of the fuel vent/drain lines, the thermos type fuel caps, and the fuel filler compartment cover in accordance with Piper Service Bulletin (SB) No. 340. A General Aviation Airworthiness Alert was published in the October, 1988 issue of the Advisory Circular 43-16, copy enclosed, which addresses precautions to be taken to avoid water and other fuel contaminants in general aviation aircraft. Further action was taken by Piper on November 4, 1988, with the issuance of FAA approved Piper SB No. 827A, which revised the fuel system draining procedures of a previous 1986 SB No. 827 and announced the availability of an Apache dual fuel drain kit. The FAA investigation team considered the preflight inspection procedures for Apache airplanes to be adequate, and will minimize water entrapment in the tanks if the inspections are performed in accordance with the earlier Piper SB No. 827.

The design, test, and procurement of internal "wedges" in the forward and aft inboard corners of the fuel tanks installed in Apache and Aztec aircraft with non-baffled fuel tanks, and larger capacity fuel bowls for Aztec aircraft with baffled fuel tanks, has proven to take longer than originally expected. We have received a final draft copy of Piper SB kits and enlarged fuel bowl kits for PA-23 Apache and Aztec airplanes. Unfortunately, these kits are not available at this time. We intend to issue a Notice of Proposed Rule Making (NPRM) which will propose mandating the incorporation of SB No. 932 in PA-23 airplanes, as soon as kits are available. In the interim, a NPRM will be issued to propose mandating Piper SB No. 827A.

In your letter, you suggested grounding PA-23 aircraft until the problem is corrected. We believe such action would be unfair to the majority of PA-23 owners and operators who properly operate and maintain their fuel systems in accordance with the applicable Service Letters, Service Bulletins, and Alerts. Based on available data, we believe that most water entrapment problems occur primarily in airplanes with low utilization and that the major causes of water-in fuel problems on PA-23 airplanes are loose filler cap seals and blocked vent/drain lines.

We believe that the actions we have taken have been effective in minimizing fuel contamination problems and that the proposed action on SB No. 827A and SB No. 932 will provide further safeguards to controlling fuel contamination in Piper Pa-23 airplanes.

 

Sincerely,

Barry D. Clements, Manager,
Small Airplane Directorate
Aircraft Certification Division

Enclosures

Airworthiness Directive 88-21-07

General Aviation Airworthiness Alerts AC No. 43-16

cc:
ACE-115A
ACE-107 (Alpiser)

 

"Nothing in this letter (the above one and the FAA's corrected version of it that follows [SumpThis]) speaks to or corrects the problem of the tank itself; i.e., the after inboard corner of every tank is below the outlet and will trap large amounts of water, which cannot be drained--regardless of how it got there." (Norman L. Horton)

Horton's above comment is handwritten on the bottom right of the last page of the letter.(SumpThis)


 

Small Airplane Directorate

601 E. 12th Street
Kansas City, MO 64106

JAN 29 1990

 

Messrs. Norman L. Horton and Jerry L. Wells
Aviation Safety and Management Consultants
4582 Old Stage Road
Central Point, Oregon 97502

 

Gentlemen:

 

Our letter to you on January 24, 1990, concerning the Piper PA-23 fuel contamination issue, omitted the last line of the first page and incorrectly numbered page 2 as page 3.

 

We are enclosing a correted copy of this letter and regret any inconvenience it may have caused you.

Sincerely,

Barry D. Clements, Manager,
Small Airplane Directorate
Aircraft Certification Division

Enclosure

 

Small Airplane Directorate

601 E. 12th Street
Kansas City, MO 64106

JAN 29 1990

 

Messrs. Norman L. Horton and Jerry L. Wells
Aviation Safety and Management Consultants
4582 Old Stage Road
Central Point, Oregon 97502

 

Gentlemen:

 

Administrator Busey has asked me to respond to your letter of December 21, 1989, concerning fuel contamination in Piper PA-23 airplanes. While your letter fully describes the action you have taken to alleviate the problem, it implies that the Federal Aviation Administration (FAA) has ignored your suggestions for corrective action and has made little effort to correct the problem.

 

In response to service reports and inquiries from your organization, the FAA established a team in 1987, to conduct an independent evaluation of the Piper PA-23 fuel system, with respect to water contamination and drain provisions. Mr. Horton was invited to participate, but was unable to do so because of a previous commitment. As a result of the investigation, the FAA issued Airworthiness Directive 88-21-07, copy enclosed, which requires repetitive inspections of the fuel vent/drain lines, the thermos type fuel caps, and the fuel filler compartment cover in accordance with Piper Service Bulletin (SB) No. 340. A General Aviation Airworthiness Alert was published in the October, 1988 issue of the Advisory Circular 43-16, copy enclosed, which addresses precautions to be taken to avoid water and other fuel contaminants in general aviation aircraft. Further action was taken by Piper on November 4, 1988, with the issuance of FAA approved Piper SB No. 827A, which revised the fuel system draining procedures of a previous 1986 SB No. 827 and announced the availability of an Apache dual fuel drain kit. The FAA investigation team considered the preflight inspection procedures for Apache airplanes to be adequate, and will minimize water entrapment in the tanks if the inspections are performed in accordance with the earlier Piper SB No. 827.

The design, test, and procurement of internal "wedges" in the forward and aft inboard corners of the fuel tanks installed in Apache and Aztec aircraft with non-baffled fuel tanks, and larger capacity fuel bowls for Aztec aircraft with baffled fuel tanks, has proven to take longer than originally expected. We have received a final draft copy of Piper SB No. 932 which announces installation instructions for "wedge" kits (Emphasis added by SumpThis to indicate what was omitted in the first version of this letter) and enlarged fuel bowl kits for PA-23 Apache and Aztec airplanes. Unfortunately, these kits are not available at this time. We intend to issue a Notice of Proposed Rule Making (NPRM) which will propose mandating the incorporation of SB No. 932 in PA-23 airplanes, as soon as kits are available. In the interim, a NPRM will be issued to propose mandating Piper SB No. 827A.

In your letter, you suggested grounding PA-23 aircraft until the problem is corrected. We believe such action would be unfair to the majority of PA-23 owners and operators who properly operate and maintain their fuel systems in accordance with the applicable Service Letters, Service Bulletins, and Alerts. Based on available data, we believe that most water entrapment problems occur primarily in airplanes with low utilization and that the major causes of water-in fuel problems on PA-23 airplanes are loose filler cap seals and blocked vent/drain lines.

We believe that the actions we have taken have been effective in minimizing fuel contamination problems and that the proposed action on SB No. 827A and SB No. 932 will provide further safeguards to controlling fuel contamination in Piper Pa-23 airplanes.

 

Sincerely,

Original Signed By
Barry D. Clements

Barry D. Clements, Manager,
Small Airplane Directorate
Aircraft Certification Division

Enclosures

Airworthiness Directive 88-21-07

General Aviation Airworthiness Alerts AC No. 43-16

 

 

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