AD 95-26-04

This amendment supersedes an existing airworthiness directive (AD), applicable to Robinson Helicopter Company (RHC) Model R22 helicopters, that currently requires revisions to the Limitations section, the Normal Procedures section, and the Emergency Procedures section of the R22 Rotorcraft Flight Manual, revised February 4, 1993. These revisions limit operations in high winds and turbulence; provide information about main rotor (M/R) stall and mast bumping; and provide recommendations for avoiding these situations. Additionally, emergency procedures are provided for use should certain conditions be encountered. This action would require similar revisions to the Limitations, Normal Procedures and Emergency Procedures sections required by the existing AD, but the revision to the Limitations section would prohibit only pilots without a certain level of experience and training from operating in the flight conditions specified. This action is prompted by data that indicates pilots who possess a certain level of experience and training are more able to recognize and react to the adverse meteorological conditions specified in the AD. The actions specified by this AD are intended to prevent M/R stall or mast bumping, which could result in the M/R blades contacting the fuselage causing failure of the M/R system and subsequent loss of control of the helicopter.

Final rule

95-26-04 ROBINSON HELICOPTER COMPANY: Amendment 39-9462. Docket No. 95-SW-29-AD. Supersedes AD 95-04-14, Amendment 39-9166.

Applicability: Model R22 helicopters, 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 (b) 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 before further flight, unless accomplished previously.

NOTE 2: Regardless of the experience level of the pilot manipulating the controls or the amount or quality of the awareness training received by the pilot manipulating the controls, these changes to the flight manual are in no way intended to authorize flight in any condition(s) or under any circumstance(s) that are otherwise contrary to other Federal Aviation Regulations.

To prevent main rotor (M/R) stall or mast bumping, which could result in the M/R blades contacting the fuselage causing failure of the M/R system, and subsequent loss of control of the helicopter, accomplish the following:

(a) Insert the following information into the Model R22 Rotorcraft Flight Manual. Compliance with the Limitations section is mandatory. The Normal Procedures and Emergency Procedures sectionsare informational.

LIMITATIONS SECTION

The following limitations (1-3) are to be observed unless the pilot manipulating the controls has logged 200 or more flight hours in helicopters, at least 50 of which must be in the RHC Model R22 helicopter, and has completed the awareness training specified in Special Federal Aviation Regulation (SFAR) No. 73, issued February 27, 1995.
(1) Flight when surface winds exceed 25 knots, including gusts, is prohibited.
(2) Flight when surface wind gust spreads exceed 15 knots is prohibited.
(3) Continued flight in moderate, severe, or extreme turbulence is prohibited.

Adjust forward airspeed to between 60 knots indicated airspeed (KIAS) and 0.7 Vne, but no lower than 57 KIAS, upon inadvertently encountering moderate, severe, or extreme turbulence.

Note: Moderate turbulence is turbulence that causes: (1) changes in altitude or attitude; (2) variations in indicated airspeed; and (3) aircraft occupants to feel definite strains against seat belts.

NORMAL PROCEDURES SECTION NOTE

Until the FAA completes its research into the conditions and aircraft characteristics that lead to main rotor blade/fuselage contact accidents, and corrective type design changes and operating limitations are identified, Model R22 pilots are strongly urged to become familiar with the following information and comply with these recommended procedures.

Main Rotor Stall: Many factors may contribute to main rotor stall and pilots should be familiar with them. Any flight condition that creates excessive angle of attack on the main rotor blades can produce a stall. Low main rotor RPM, aggressive maneuvering, high collective angle (often the result of high-density altitude, over-pitching [exceeding power available] during climb, or high forward airspeed) and slow response to the low main rotor RPM warning horn and light may result in main rotor stall. The effect of these conditions can be amplified in turbulence. Main rotorstall can ultimately result in contact between the main rotor and airframe. Additional information on main rotor stall is provided in the Robinson Helicopter Company Safety Notices SN-10, SN-15, SN-20, SN-24, SN-27, and SN-29.

Mast Bumping: Mast bumping may occur with a teetering rotor system when excessive main rotor flapping results from low "G" (load factor below 1.0) or abrupt control input. A low "G" flight condition can result from an abrupt cyclic pushover in forward flight. High forward airspeed, turbulence, and excessive sideslip can accentuate the adverse effects of these control movements. The excessive flapping results in the main rotor hub assembly striking the main rotor mast with subsequent main rotor system separation from the helicopter.

To avoid these conditions, pilots are strongly urged to follow these recommendations:
(1) Maintain cruise airspeeds between 60 KIAS and less than 0.9 Vne, but no lower than 57 KIAS.
(2) Use maximum "power-on" RPM atall times during powered flight.
(3) Avoid sideslip during flight. Maintain in-trim flight at all times.
(4) Avoid large, rapid forward cyclic inputs in forward flight, and abrupt control inputs in turbulence.

EMERGENCY PROCEDURES SECTION

(1) RIGHT ROLL IN LOW "G" CONDITION
Gradually apply aft cyclic to restore positive "G" forces and main rotor thrust. Do not apply lateral cyclic until positive "G" forces have been established.

(2) UNCOMMANDED PITCH, ROLL, OR YAW RESULTING FROM FLIGHT IN TURBULENCE.
Gradually apply controls to maintain rotor RPM, positive "G" forces, and to eliminate sideslip. Minimize cyclic control inputs in turbulence; do not overcontrol.

(3) INADVERTENT ENCOUNTER WITH MODERATE, SEVERE, OR EXTREME TURBULENCE.
If the area of turbulence is isolated, depart the area; otherwise, land the helicopter as soon as practical.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used when approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(c) Special flight permits, pursuant to sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199), will not be issued.

(d) This amendment becomes effective on January 26, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 95-04-14, Amendment 39-9166, which superseded Priority Letter AD 95-02-03, issued January 12, 1995, which is applicable to RHC Model R22 helicopters, was published in the Federal Register on October 12, 1995 (60 FR 53148). That action proposed to require revisions to the Limitations section, the Normal Procedures section, and the Emergency Procedures section of the R22 Rotorcraft Flight Manual, revised February 4, 1993. These revisions limit operations in high winds and turbulence; provide information about M/R stalls and mast bumping; and provide recommendations for avoiding these situations. Additionally, emergency procedures are provided for use should certain conditions be encountered. This supersedure will reduce limitations for pilots who have the flight experience specified by the AD and who have completed the SFAR No. 73 training.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comment received. The sole commenter agrees with the FAA's proposal that the FAA's exemption of those pilots with sufficient training and experience from limitations that might in some cases substantially restrict their Model R22 flight operations is justified.

After careful review of the available data, including the comment, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 800 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately one-half work hour per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $24,000.

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.

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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 USC 106(g), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by removing Amendment 39-9166, and by adding a new airworthiness directive (AD), Amendment 39-9462, to read as follows: