Date of issue: June 24, 1999

Applicability: The following very high frequency (VHF) navigation receivers that are installed on, but not limited to, Learjet Model 31A, Fokker Model F27-50, and British Aerospace Model ATP airplanes:

- VN 411B, BPN 3614004-4101, all serial numbers, that are currently at Modification Status 18, 19, or 20;
- VN 411B, BPN/KPN 3614004-4101/066-1101-00, all serial numbers, that are currently at Modification Status 18, 19, or 20;
- VN 411B, P/N 066-1101-00, serial numbers up to and including 4229, that are currently at Modification Status 18, 19, or 20; and
- VN 411B, P/N 066-1101-/31/40/50, serial numbers up to and including 10799, that are currently at Modification Status 19 or 20.

Effective date: August 12, 1999.

Compliance : Required as indicated in FAA AD 99-12-06

99-12-06 ALLIEDSIGNAL INC.: Amendment 39-11190; Docket No. 95-CE-91-AD.

Applicability: The following very high frequency (VHF) navigation receivers that are installed on, but not limited to, Learjet Model 31A, Fokker Model F27-50, and British Aerospace Model ATP airplanes:

- VN 411B, BPN 3614004-4101, all serial numbers, that are currently at Modification Status 18, 19, or 20;

- VN 411B, BPN/KPN 3614004-4101/066-1101-00, all serial numbers, that are currently at Modification Status 18, 19, or 20;

- VN 411B, P/N 066-1101-00, serial numbers up to and including 4229, that are currently at Modification Status 18, 19, or 20; and

- VN 411B, P/N 066-1101-/31/40/50, serial numbers up to and including 10799, that are currently at Modification Status 19 or 20.

NOTE 1: This AD applies to each airplane in which a VHF navigation receiver identified in the preceding applicability provision has been installed, 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 (d) 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 in the body of this AD, unless already accomplished.

To prevent VHF navigation receiver interference from frequency modulation (FM) radio station broadcast frequencies, which could cause distortion of the navigation audio and deflection of the desired flight path of the airplane during landing operations with possible loss of control of the airplane, accomplish the following:

(a) Within the next 90 calendar days after the effective date of this AD or upon replacement or repair of any affected AlliedSignal VHF navigation receiver, whichever occurs first, remove the navigation receiver and install one where an AlliedSignal Bendix/King service center has incorporated Modification 21, in accordance with AlliedSignal Bendix/King Service Bulletin VN 411B-21, dated November 1996.

(b) As of the effective date of this AD, no person may install, on any airplane, one of the affected VHF navigation receivers that does not have Modification 21 incorporated in accordance with AlliedSignal Bendix/King Service Bulletin VN 411B-21, dated November 1996.

(c) 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 airplane to a location where the requirements of this AD can be accomplished.

(d) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Wichita, Kansas 67209. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Wichita ACO.

(e) The removal and installation required by this AD shall be done in accordance with AlliedSignal Bendix/King Service Bulletin VN 411B-21, dated November 1996. 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 AlliedSignal, Inc., 23500 W. 105th Street, Olathe, Kansas 66051-1950. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(f) This amendment becomes effective on July 23, 1999.

FOR FURTHER INFORMATION CONTACT:

Mr. Roger Souter, Aerospace Engineer, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, Kansas 67209; telephone: (316) 946-4134, facsimile: (316) 946-4407.