AD 98-21-09

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AD Number:
98-21-09
Document Type:
AD Final Rules
Docket Number:
98-SW-45-AD
Subject Heading:
Airworthiness Directives; Robinson Helicopter Company Model R22 Helicopters
Subject:
Fuel Tank Vent Tube(s) In Mast Fairing
Status:
Current
Citation:
(Federal Register: November 24, 1998 (Volume 63, Number 226))
Citation Publish Date:
11/24/1998
Effective Date:
12/09/1998
Make:
Robinson Helicopter Company
Model:
R22 | R22 ALPHA | R22 BETA | R22 MARINER
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 (63 FR 64849 NO. 226 11/24/98)
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 98-21-09
CITATION:   [Federal Register: November 24, 1998 (Volume 63, Number 226)]

PAGE NUMBER:   [Page 64849]

DOCKET NUMBER:   98-SW-45-AD

AMENDMENT:   39-10908

AD NUMBER:   98-21-09

SUBJECT HEADING:   Airworthiness Directives; Robinson Helicopter Company Model R22 Helicopters

ACTION:   Final rule; request for comments

SUMMARY:   This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-21-09, which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (RHC) Model R22 helicopters by individual letters. This AD requires installing fuel tank vent tube(s), with modified attachment to the mast tube, if not previously accomplished; installing a spring into the flexible tube leading to the main fuel tank; and installing a spring into the flexible tube leading to the auxiliary fuel tank, if an auxiliary fuel tank is installed. This amendment is prompted by an incident in which the flexible vent connecting the rigid vent tube to the main fuel tank kinked, resulting in fuel starvation and a hard landing after uncommanded engine shutdown. The actions specified by this AD are intended to prevent fuel starvation, loss of engine power, and a subsequent forced landing.

DATES:   Effective December 9, 1998. To all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-21-09, issued on September 28, 1998, which contained the requirements of this amendment. Comments for inclusion in the Rules Docket must be received on or before January 25, 1999.

ADDRESSES:   Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional
Counsel, Southwest Region, Attention: Rules Docket No. 98-SW-45-AD, 2601 Meacham Blvd., Room 663, Fort Worth,
Texas 76137.

FOR FURTHER INFORMATION CONTACT:   Ms. Elizabeth Bumann, Aerospace Engineer, FAA, Los Angeles
Aircraft Certification Office, Propulsion Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone (562)
627-5265, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:  

On September 28, 1998, the FAA issued Priority Letter AD 98-21-09, applicable to RHC Model R22 helicopters, which requires installing fuel tank vent tube(s), with modified attachment to the mast tube, if not previously accomplished; installing a spring into the flexible tube leading to the main fuel tank; and installing a spring into the flexible tube leading to the auxiliary fuel tank, if an auxiliary fuel tank is installed. That action was prompted by an incident in which a hard landing resulted from an uncommanded engine shutdown. The pilot reported that the fuel quantity gauges indicated fuel consumption from the auxiliary fuel tank only, with the main fuel tank indication remaining at or near full. When the auxiliary fuel tank quantity gauge reached empty, the engine misfired and then stopped. An inspection revealed a kink in the flexible vent tube connecting the rigid vent tube to the main fuel tank. Two similar incidents have occurred with this single vent design. This condition, if not corrected, could result in fuel starvation, loss of engine power, and a subsequent forced landing.

The FAA has reviewed RHC R22 Service Bulletin SB-83 dated March 4, 1997 (SB-83), which describes procedures for modifying attachment of the fuel tank vent(s); and RHC R22 Service Bulletin SB-84 dated September 8, 1998 (SB-84), which describes procedures for installing springs in the vent tubes to prevent kinks. RHC kit instructions KI-118-1 R22 Fuel Tank Vent Upgrade For Ships Without Auxiliary Tank, dated March 4, 1997, and RHC KI-118-2 R22 Fuel Tank Vent Upgrade For Ships With Auxiliary Tank, dated April 29, 1997, which describe procedures for installing fuel tank vent tube(s), part number (P/N) A731-3, are attached to SB-83. RHC kit instructions KI-140 R22 Fuel Tank Vent Upgrade For Fuel Tanks With Single Vent, dated September 3, 1998, which describe procedures for installing springs into the flexible tube leading to the main fuel tank, and, if an auxiliary fuel tank is installed, into the flexible tube leading to the auxiliary fuel tank, are attached to SB-84.

Since the unsafe condition described is likely to exist or develop on other RHC Model R22 helicopters of the same type design, the FAA issued priority letter AD 98-21-09 to prevent fuel starvation, loss of engine power, and a subsequent forced landing. The AD requires, within 25 hours time-in-service (TIS) or 30 calendar days after the effective date of this AD, whichever occurs first, installing fuel tank vent tube(s), P/N A731-3, with modified attachment to the mast tube, if not previously accomplished; installing a spring, P/N B408-2, into the flexible tube leading to the main fuel tank; and installing a spring, P/N B408-1, into the flexible tube leading to the auxiliary fuel tank, if an auxiliary fuel tank is installed. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability of the helicopter. Therefore, the installations are required prior to further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on September 28, 1998, to all known U.S. owners and operators of RHC Model R22 helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

The only change to the priority letter in this published version of this AD is that the reference in NOTE 1 to the alternative methods of compliance is corrected from paragraph "(d)" to paragraph "(c)".

The FAA estimates that 700 helicopters of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per helicopter to accomplish the required actions, and the average labor rate is $60 per work hour. Required parts will cost approximately $65 for each helicopter without an auxiliary fuel tank installed or $105 for each helicopter with an auxiliary fuel tank installed. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $225 per helicopter for helicopters with an auxiliary fuel tank installed, or $185 per helicopter for helicopters without an auxiliary fuel tank installed.

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 should 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 No. 98-SW-45-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. 106(g) 40113, 44701.

§ 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

REGULATORY TEXT:  
98-21-09 ROBINSON HELICOPTER COMPANY: Amendment 39-10908. Docket No. 98-SW-45-AD.

Applicability: Model R22 helicopters, serial numbers 0002 through 1451, inclusive, certificated in any category.

NOTE 1: This AD applies to each helicopter 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 helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (c) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required within 25 hours time-in-service or 30 calendar days after the effective date of this AD, whichever occurs first, unless accomplished previously.

To prevent fuel starvation, loss of engine power, and a subsequent forced landing, for helicopters overhauled by Robinson Helicopter Company (RHC) prior to January 1, 1991, which do not have a main fuel tank (only) with dual vent tubes, or, if the auxiliary fuel tank is installed, do not have a crossover vent tube between the fuel tanks, accomplish the following:

(a) Visually inspect the fuel tank vent tube(s) in the mast fairing. If each fuel tank vent tube is attached only to the mast tube at two locations, the helicopter complies with the requirements of paragraph (a) of this AD. If each fuel tank vent tube is attached to the mast tube at one location, and to the rain scupper (channel), part number (P/N) A032-16, on the fuel tank cowling at another location:

(1) For helicopters without an auxiliary fuel tank installed, remove the existing vent tube, P/N A731-1, and install an airworthy vent tube, P/N A731-3, with flexible tube, P/N A729-7, using an MS27039C0806 screw and AN960-8L washer (alternate P/N NAS1149FN816P) at the lower clamp, P/N A695-1 (see Figure 1).

(2) For helicopters with an auxiliary fuel tank installed, remove the existing main fuel tank vent tube, P/N A731-1, and auxiliary fuel tank vent tube, P/N A731-2, and install airworthy vent tubes, P/N A731-3, with flexible tube, P/N A729-7, for main tank and flexible tube, P/N A729-17, for auxiliary tank using MS27039C0807 screw and AN960-8L washer (alternate P/N NAS1149FN816P) at lower clamp, P/N A695-1 (see Figure 2).

(b) Install spring, P/N B408-2, into the flexible vent tube, P/N A729-7, leading to the main fuel tank; and install spring, P/N B408-1, into the flexible vent tube, P/N A729-17, leading to the auxiliary fuel tank (if an auxiliary fuel tank is installed), in accordance with RHC kit instructions KI-140 R22 Fuel Tank Vent Upgrade For Fuel Tanks With Single Vent, dated September 3, 1998.

NOTE 2: RHC R22 Service Bulletin SB-83, dated March 4, 1997, and RHC R22 Service Bulletin SB-84, dated September 8,1998, pertain to the subject of this AD.

(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, Los Angeles Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.

(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 helicopter to a location where the requirements of this AD can be accomplished.

(e) This amendment becomes effective on December 9, 1998, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-21-09, issued September 28, 1998, which contained the requirements of this amendment.



HELICOPTER WITHOUT AUXILIARY FUEL TANK
FIGURE 1
AD 98-21-09





HELICOPTER WITH AUXILIARY FUEL TANK

FIGURE 2
AD 98-21-09


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