- Effective
- September 24, 1999
- Published
- August 20, 1999 · 64 FR 45435–45436
- Issued
- August 12, 1999
- Model
- 600N
- Data sheet
- TCDSH3WE
- Registered aircraft
- 26 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-11264
- Docket
- 98-SW-16-AD
- Issued as
- Final rule
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. Only the govinfo PDF is the legal edition. DRS record last changed May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| Official PDF | 118 KB | 86d94f3e…c05e066 | 99-21572.pdf on govinfo.gov |
| FAA DRS HTML | 47 KB | 426d4f6e…75f602e | FAA DRS (API key needed) |
| Federal Register text | 12 KB | a2cbbb87…4a64935 | 99-21572.txt on federalregister.gov |
On this page
Summary
This amendment adopts a new airworthiness directive (AD), applicable to MD Helicopters, Inc. (MDHI) Model 600N helicopters, that requires applying serial numbers to several life-limited components related to pitch control and removing and replacing the components according to new life-limits. This amendment is prompted by fatigue tests that indicate a need for shorter service lives for these components. The actions specified by this AD are intended to prevent failure of the collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, which can cause loss of collective pitch control, and subsequent loss of control of the helicopter.
The airworthiness directive
99-17-18 MD HELICOPTERS INC.: Amendment 39-11264; Docket No. 98-SW-16-AD.
Applicability: Model 600N 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 otherwise 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 request approval for an alternative method of compliance in accordance with paragraph (e) 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 the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent failure of the collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, loss of collective pitch control, and subsequent loss of control of the helicopter, accomplish the following:
(a) On or before reaching 400 hours time-in-service (TIS), apply the serial number (S/N) listed in McDonnell Douglas Helicopter Systems Service Bulletin No. 600N-009, dated February 24, 1998 (SB), to the two collective stick housings, P/N's 369A7347 and 369A7820; the pilot collective pitch control tube, P/N 369A7348; and the co-pilot collective pitch control tube, P/N 369A7809, in the most visible spot for the specified aircraft S/N.
(b) Remove and replace the following flight control components according to the stated life-limits:
P/N Component Life-Limit (Hours TIS) 369A7347 Housing, collective stick 450 369A7348 Tube, collective pitch control (pilot) 400 369H7354-3 Tube assembly, collective pitch (pilot) 600 369A7809 Tube, collective pitch control (co-pilot) 1,800 369A7820 Housing, collective stick 450 369H7837 Housing, collective stick 450 369H7838-3 Tube assembly, collective pitch (co-pilot) 1,000
(c) Create a component history card or equivalent record in the helicopter log and record the helicopter TIS at installation for each of the components listed in paragraph (b) of this AD.
(d) This AD revises the Airworthiness Limitations Section of the maintenance manual by reducing the life-limits of the pilot collective pitch control tube, the collective stick housings, and the collective pitch tube assemblies, and adding the co-pilot collective pitch control tube to the Airworthiness Limitations section, Component Mandatory Replacement Schedule.
(e) 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 2: 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.
(f) 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.
(g) The application of serial numbers shall be done in accordance with the Accomplishment Instructions of McDonnell Douglas Helicopter Systems Service Bulletin No. 600N-009, dated February 24, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from MD Helicopters Inc., Attn: Customer Support Division, 5000 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9797, telephone 1-800-388-3378 or 480-891-6342, datafax 480-891-6782. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective September 24, 1999.
Rule preamble
The FAA’s background, reasoning and cost estimate, published with the AD.
Supplementary information
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that is applicable to MDHI Model 600N helicopters was published in the Federal Register on March 23, 1999 (64 FR 13936). That action proposed to require applying serial numbers to several life-limited components related to pitch control and removing and replacing the components according to new life-limits.
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed with the following exceptions. Since the publication of the Notice of Proposed Rulemaking (NPRM), the name of the type certificate holder has changed from "McDonnell Douglas Helicopter Systems" to "MD Helicopters, Inc." Also, the NPRM contained an error in the part number for the "Housing, collective stick." The part number should have been "369A7347" but was incorrectly listed as "1369A7347." A part number "1369A7347" does not exist for the affected model helicopter. Both the name and the part number have been changed in this final rule AD; the FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
The FAA estimates that 16 helicopters of U.S. registry will be affected by this AD, that it will take approximately 0.5 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $480.
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, Incorporation by reference, 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:
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 26
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1997 | 5 |
|---|---|
| 1998 | 4 |
| 2000 | 2 |
| 2001 | 1 |
| 2002 | 2 |
| 2005 | 1 |
| 2006 | 1 |
| 2007 | 1 |
| 2008 | 2 |
| 2010 | 1 |
6 with no year recorded