Heated Windshield Test Procedure

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Piper Aircraft, Inc. 2926 Piper Drive Vero Beach, FL, U.S.A. 32960 Date: August 17, 2016 (S) (OVeR) SERVICE LETTER NO. 1204 Subject: Heated WindSHield teSt Procedure ModelS affected: Serial nuMberS affected: PA-46-350P Mirage/M350 4622003 through 4622200; 4636001 and Up PA-46R-350T Matrix 4692001 and Up PA-46-500TP Meridian/M500 4697001 and Up PA-46-600TP M600 4698001 and Up coMPliance tiMe: Owner/operator discretion aPProval: The engineering aspects of this service document have been shown to comply with the applicable Federal Aviation Regulations and are FAA approved. PurPoSe: In-cockpit ammeter readings are erroneously being used to assess the serviceability of heated windshields installed in the affected airplanes. This service letter provides an approved method of determining heated windshield serviceability. NOTe: This service letter is applicable to aircraft that have a factory-installed heated windshield. ATA/JASC: 3040 Maintenance alert Service letter no. 1204 PaGe 2 of 4 inStructionS: NOTe: Pilot operating handbooks (POHs) for the Piper PA-46-350P and PA-46R-350T models and the airplane maintenance manuals for PA-46-310P and PA-46-350P provide a check for the function of the heated windshield. That procedure reads ammeter increases when the heater is set on high and low. While that is a valid check of the functioning of the heater, the specific ammeter values included in some POHs are only approximations and are not to be used to assess the serviceability of a heated windshield. NOTe: The applicable airplane maintenance manuals will be updated to include the following test method during the next revision cycle. The applicable POHs will be revised to remove references to specific amp values. The only Piper approved method to determine the serviceability of the heated windshield is the following: NOTe: This test is to be performed in ambient temperatures of 75° F +/– 10° (24° C +/– 5.56°). a. Remove the glareshield to access the heated windshield terminal blocks. See Figure 1 for terminal block locations. b. Resistance is to be tested with power removed from the heated windshield. When the windshield terminal blocks are exposed: 1) For all affected PA-46R-350T Matrix, PA-46-500TP Meridian/M500, and PA-46-600TP M600; PA-46-350P Mirage/M350 models 4622172 and up only: a) Measure resistance between terminal P1 and P2. Resistance must be 1.15 ohms +/– 10%. b) Measure resistance between terminal P1 and P3. Resistance must be 1.58 ohms +/– 10%. 2) For PA-46-350P Mirage models 4622003 through 4622171 only: a) Measure resistance between terminal P1 and P2. Resistance must be 1.11 ohms +/– 10%. b) Measure resistance between terminal P1 and P3. Resistance must be 1.70 ohms +/– 10%. 3) If the measurements fail to meet specified values in either step 1) or 2) above, for the applicable aircraft, then the windshield must be replaced. Service letter no. 1204 PaGe 3 of 4 figure 1 Heated Windshield Terminal Block Locations P2 (WIRE D15D12) HEATED WINDSHIELD FUSELAGE HARNESS P1 (WIRE D15B12) P3 (WIRE D15E12) A427 AFT UP GLARESHIELD REMOVED TO ACCESS HEATER TERMINALS Service letter no. 1204 PaGe 4 of 4 Material reQuired: N/A availabilitY of PartS: N/A effectivitY date: This service letter is effective upon receipt. SuMMarY: Please contact your Factory Authorized Piper Service Facility to make arrangements for compliance with this service letter in accordance with the compliance time indicated. NOTe: Please notify the factory of any address/ownership corrections. Changes should include aircraft model, serial number, and current owner’s name and address. Corrections and/or changes should be directed to: PIPeR AIRCRAFT, INC. Attn: Customer Service 2926 Piper Drive Vero Beach, FL 32960