# AD 84-14-01: T4 Indicator System Check - Type: Airworthiness directive - Status: Current - Products: Honeywell International LTS101-600A-2 - Superseded by: Nothing supersedes this AD - Product type: Engine - Registered aircraft: 32 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9E85D682AB82F8BE862568420059A255.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/84-14-01 ## The airworthiness directive 84-14-01 AVCO LYCOMING: Letter issued July 20, 1984. Pursuant to the authority of the Federal Aviation Act of 1958, delegated to me by the Administrator, the following AD is issued and made applicable to Avco Lycoming LTS101-600A-2 model engines. Compliance required in the sequence indicated, unless already accomplished: 1. Perform a T4 indicator system check on those AS350D helicopters having Brion Leroux T4 indicator part number 5626-524-00-00 installed, in accordance with Aerospatiale Maintenance Manual Maintenance Work Card (MWC) 77.00.00.501 at four approximately equal increments between 680 degrees C and 820 degrees C, within the next 50 engine operating hours and thereafter at intervals not to exceed 300 engine operating hours. (NOTE: Approved calibration equipment is described in Aerospatiale Telex Number AHC/SE/BH/84T/114T, paragraph EE.) Comply with following instructions (A), (B), and (C) if the T4 indicator system error is greater than zero plus minus 5 degreesC at any of the four increments and comply additionally with paragraph 4 below prior to further flight if the T4 indicator system reads low by 15 degrees C or greater at any of the four increments. (A) Check that the thermocouple loop resistance (without indicator) is not greater than 5.7 OHMS. (B) If the thermocouple loop resistance (without indicator) is greater than 5.7 OHMS, check the harness for loose or contaminated connections. Tighten, clean, or replace the aircraft harness components, or check and replace engine thermocouple components as required to bring the resistance to 5.7 OHMS or less. (C) When the thermocouple loop resistance (without indicator) is 5.7 OHMS or less, calibrate the T4 indicator system to result in zero plus minus 5 degrees C error at a selected point within the range of 760 degrees C to 770 degrees C, by adjusting the indicator setscrew (reference MWC 77.00.00.501) or replacing the indicator if required. 2. Perform an engine condition checkin accordance with the Aerospatiale AS350D helicopter flight manual, Section II, paragraph 10, within the next 50 engine operating hours. If the condition of the engine is proved to be unsatisfactory and cannot be corrected through normal maintenance procedures, comply with paragraph 4 below prior to further flight. 3. Perform an engine vibration survey in accordance with Avco Lycoming Service Bulletin Number LTS 101A-71-00-0061, Section II, Item B, within the next 50 engine operating hours. If the revised vibration limits are exceeded, comply with paragraph 4 below prior to further flight. 4. Comply with the accomplishment instructions in Avco Lycoming Service Bulletin Number LTS 101A-71-00-0061, Section II, Items F, G, H, and I, at each 600 hour periodic inspection and prior to further flight as directed by the preceding paragraphs. Aircraft may be ferried in accordance with the provisions of Federal Aviation Regulations (FAR) 21.197 and 21.199 to a base where the AD can be accomplished. Upon request of an operator, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, Engine Certification Office, FAA, New England Region. This airworthiness directive becomes effective upon receipt. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E5NE](https://openairdocs.org/tcds/E5NE): Intermountain Turbine Services Inc.; names 1 of 13 models: LTS101-600A-2 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 32 (0 by airframe model, 32 by engine model) - Makers: Bell 12, Messerschmitt-Bolkow-Blohm 9, MBB 3, Messerschmitt 3, Aerospatiale 2, Eurocopter Deutschland 2, S N I A S 1 Models with the most aircraft: - [Lycoming LTS-101 series](https://openairdocs.org/engine/lycoming-lts-101-series): 29 aircraft (engine model) - [Lycoming LTS-101 600A series](https://openairdocs.org/engine/lycoming-lts-101-600a-series): 3 aircraft (engine model) All 2 models: https://openairdocs.org/ad/84-14-01/models.md Every aircraft: https://openairdocs.org/ad/84-14-01/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.