AD 2001-01-02

This amendment adopts a new airworthiness directive (AD) that applies to certain British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes that are equipped with certain nose landing gear units. This AD requires you to inspect the steering jack assembly to assure proper clearance between the bush heads on the steering plates and the shim on the steering jack trunnions and to assure that there is adequate lubrication at both trunnions and the eye end fitting. This AD also requires you to adjust the clearance and provide adequate lubrication, as necessary. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent cracked steering jack piston rods caused by inadequate clearance or inadequate lubrication of the steering jack pivot points. The condition could result in failure of the nose wheel steering system with consequent loss of airplane control.

Final rule

2001-01-02 BRITISH AEROSPACE: Amendment 39-12072; Docket No. 99-CE-83-AD.

(a) What airplanes are affected by this AD? This AD affects Models HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes, all serial numbers, that are:

(1) equipped with a nose landing gear unit 1873, B00A702852A, B00A703064A, or B00A703056A; and

(2) certificated in any category.

(b) Who must comply with this AD? Anyone who wishes to operate any of the above airplanes must comply with this AD.

(c) What problem does this AD address? The actions specified by this AD are intended to prevent cracked steering jack piston rods caused by inadequate clearance or inadequate lubrication of the steering jack pivot points. The condition could result in failure of the nose wheel steering system with consequent loss of airplane control.

(d) What actions must I accomplish to address this problem? To address this problem, you must accomplish the following:Action
Compliance Time
Procedures
(1) Inspect the steering jack assembly to assure proper clearance between the bush heads on the steering plates and the shim on the steering jack trunnions and to assure that there is adequate lubrication at both trunnions and the eye end fitting
Within the next 200 hours time-in-service (TIS) after March 5, 2001, the effective date of this AD, unless already accomplished
Accomplish in accordance with the instructions in APPH Ltd. Service Newsletter, Issue 2, Jetstream 31 Steering Jack Part Number 618200, as referenced in British Aerospace Mandatory Service Bulletin 32-JA 981043, dated March 5, 1999.
(2) Adjust the clearance and provide adequate lubrication, as necessary.
Prior to further flight after the inspeciton required by paragraph (d)(1) of this AD.
Accomplish in accordance with the instructions in APPH Ltd. Service Newsletter, Issure 2, Jetstream 31 Steering Jack Part Number 618200, as referenced in British Aerospace Mandatory Service Bulletin 32-JA 981043, dated March 5, 1999.


(e) 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, Small Airplane Directorate.

Note 1: 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 (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 you have not eliminated the unsafe condition, specific actions you propose to address it.

(f) Where can I get information about any already-approved alternative methods of compliance? Contact Mr. Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4059; facsimile: (816) 329-4090.

(g) 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.

(h) Are any service bulletins incorporated into this AD by reference? Actions required by this AD must be done in accordance with APPH Ltd. Service Newsletter, Issue 2, Jetstream 31 Steering Jack Part Number 618200, as referenced in British Aerospace Mandatory Service Bulletin 32-JA 981043, dated March 5, 1999. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You can get copies from British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland. You can look at copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(i) When does this amendment become effective? This amendment becomes effective on March 5, 2001.

Note 2: The subject of this AD is addressed in British AD 012-03-99.

Discussion
What events have caused this AD? The Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, recently notified the FAA that an unsafe condition may exist on certain British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes. The CAA reports incidents where cracking has occurred at the base of the thread in the steering jack piston rod, part number 618212, in the nose landing gear unit. The condition could occur on the referenced airplanes that are equipped with nose landing gear unit 1873, B00A702852A, B00A703064A, or B00A703056A.

Inadequate clearance or inadequate lubrication of the steering jack pivot points can result in unusually high operational loads. These loads could result in such cracks in the steering jack piston rod.

What are the consequences if the condition is not corrected? A cracked steering jack piston rod could result in failure of the nose wheel steering system with consequent loss of airplane control.

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 certain British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes that are equipped with certain nose landing gear units. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on October 24, 2000 (65 FR 63553). The NPRM proposed to require you to inspect the steering jack assembly to assure proper clearance between the bush heads on the steering plates and the shim on the steering jack trunnions and to assure that there is adequate lubrication at both trunnions and the eye end fitting. The NPRM also proposed to require you to adjust the clearance and provide adequate lubrication, as necessary.

Accomplishment of the proposed action would be in accordance with APPH Ltd. Service Newsletter, Issue 2, Jetstream 31 Steering Jack Part Number 618200, as referenced in British Aerospace Mandatory Service Bulletin 32-JA 981043, dated March 5, 1999.

Was the public invited to comment? Interested persons were afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

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 minor editorial corrections. We determined that these 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 300 airplanes in the U.S. registry.
What is the cost impact of this AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the inspection:

Labor Cost
Parts Cost
Total Cost Per
Airplane
Total Cost on
U.S. Operators
1 workhour X $60 per hour
.
No parts required to
accomplish the inspection
$60 per airplane
$18,000

We estimate the following costs to accomplish any necessary adjustments that are required based on the results of the inspections. We have no way of determining the number of airplanes that may need such adjustments:

Labor Cost

Parts Cost

Total Cost Per Airplane
1 workhour X $60 per hour.
No parts necessary for adjustment.
$60 per airplane.

Regulatory Impact
Does this AD impact various entities? 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 distributionof 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.

Does this AD involve a significant rule or regulatory action? 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, Incorporation by reference, 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 [Amended]
2. FAA amends 39.13 by adding a new AD to read as follows: