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No. of STCs: 29

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA03393CH	Status: Historical	App Date: 09/10/2014	Rev Date: 03/19/2018
Description: Installation of a Pratt and Whitney Canada, PT6A-140 Engine
TC Nos.: A37CE
Models: Textron Aviation Inc.208
ACO: Chicago ACO Branch, Tel: +1 (847) 294-7358

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA211CE	Status: Current	App Date: 01/24/1964	Rev Date: 12/13/2017
Description: A.P.U. Installation - Ranger Andover Model V-32D-2-1.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-113	Status: Current	App Date: 09/11/1957	Rev Date: 12/13/2017
Description: Installation of RCA Model AVQ-10 radar antenna swingaway mount SK10136 (SA3-65).
TC Nos.: A-669
Models: The Boeing CompanyDC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-139	Status: Current	App Date: 11/11/1957	Rev Date: 12/13/2017
Description: Installation of standard C-47 cargo door.
TC Nos.: A-669
Models: The Boeing CompanyDC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-15	Status: Current	App Date: 12/05/1956	Rev Date: 12/13/2017
Description: Installation of wheel well enclosure doors.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-307	Status: Historical	App Date: 07/03/1958	Rev Date: 12/13/2017
Description: Installation of 145-gallon fuel tanks. Installation of 252-gallon fuel tanks.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: Chicago ACO Branch, Tel: +1 (847) 294-7358

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-307	Status: Current	App Date: 07/03/1958	Rev Date: 12/07/2018
Description: Installation of 145-gallon fuel tanks. Installation of 252-gallon fuel tanks.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-422	Status: Current	App Date: 09/18/1959	Rev Date: 12/13/2017
Description: Installation of bird resistant windshield.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-434	Status: Current	App Date: 09/18/1959	Rev Date: 12/13/2017
Description: Picture window installation and standard window modification.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-461	Status: Current	App Date: 12/18/1959	Rev Date: 12/13/2017
Description: Installation of electrically driven emergency hydraulic pump.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-52	Status: Current	App Date: 02/22/1955	Rev Date: 12/13/2017
Description: Radome installation.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3-78	Status: Current	App Date: 07/26/1957	Rev Date: 12/13/2017
Description: Alternate Tee-Bolt radome attachment for STC SA3-52 radome installation.
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA3074NM	Status: Current	App Date: 07/23/1985	Rev Date: 02/24/2017
Description: This modification requires that the following two (2) placards be placed on the inside of the forward (L.H.) cargo door in full view of the cargo loading crew: MAXIMUM PAYLOAD CAPACITY -7500 lbs. or less, CARGO LOADING METHOD-Refer to FAA App Oper Handbk.
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3C-S1C3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA4-220	Status: Historical	App Date: 05/03/1957	Rev Date: 02/25/2016
Description: Installation of tail wheel cover and fairing
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: Chicago ACO Branch, Tel: +1 (847) 294-7358

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA4-220	Status: Current	App Date: 05/03/1957	Rev Date: 07/15/2016
Description: Installation of tail wheel cover and fairing
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA4-228	Status: Current	App Date: 05/27/1957	Rev Date: 02/25/2016
Description: Main landing gear doors, actuating system, main landing gear assist bungee, oil cooler fairing and oil cooler fixed section for aircraft with Pratt & Whitney R-1830-75, -92 or -94 engines.
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: SA4-230	Status: Current	App Date: 06/06/1957	Rev Date: 02/25/2016
Description: Installation of aileron gap closure
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04050CH	Status: Current	App Date: 01/16/2014	Rev Date: 02/12/2016
Description: Installation of Ice Protection Systems
TC Nos.: A-669
Models: The Boeing CompanyDC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04244CH	Status: Current	App Date: 02/01/2017	Rev Date: 01/18/2018
Description: Installation and Activation of a Saab Grintek Defense Impi II Asset Tracking System
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3A-SC3G, DC3C-R-1830-90C, DC3C-S4C4G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04261CH	Status: Current	App Date: 06/07/2016	Rev Date: 11/20/2017
Description: Installation of a Gear Latch & Ground Shift system
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04262CH	Status: Current	App Date: 04/25/2017	Rev Date: 02/02/2018
Description: Install placarding to restrict total payload to a maximum of six thousand pounds (6,000 lbs)
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04262CH	Status: Historical	App Date: 04/25/2017	Rev Date: 12/11/2017
Description: Install placarding to restrict total payload to a maximum of six thousand pounds (6,000 lbs)
TC Nos.: A-618, A-669
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A, DC3A-S1C3G, DC3A-S1CG, DC3A-S4C4G, DC3A-SC3G, DC3A-SCG, DC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: Chicago ACO Branch, Tel: +1 (847) 294-7358

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04263CH	Status: Current	App Date: 04/24/2017	Rev Date: 12/11/2017
Description: Install placarding to restrict passenger count to a maximum of nineteen (19) and total payload to a maximum of seven thousand five hundred pounds (7,500 lbs)
TC Nos.: A-618
Models: The Boeing CompanyDC3-G102, DC3-G102A, DC3-G103A, DC3-G202A
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04530AT	Status: Historical	App Date: 05/07/2019	Rev Date: 12/12/2021
Description: Installation of a wingtip modification on DC3C aircraft (specific models listed)
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-7C0: Chicago ACO Branch

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04530AT	Status: Current	App Date: 05/07/2019	Rev Date: 12/12/2021
Description: Installation of a wingtip modification on DC3C aircraft (specific models listed)
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04530AT	Status: Historical	App Date: 05/07/2019	Rev Date: 12/12/2021
Description: Installation of a wingtip modification on DC3C aircraft (specific models listed)
TC Nos.: A-669
Models: The Boeing CompanyDC3A-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: Chicago ACO Branch, Tel: +1 (847) 294-7358

STC Holder: Preferred Improvements LLC 11234 Hackett Rd., Apple Creek, OH 44606		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04605CH	Status: Current	App Date: 03/30/2022	Rev Date: 05/22/2024
Description: Installation of a Garmin GTS 8000 Traffic Alert and Collision Avoidance System (TCAS) II
TC Nos.: A-669
Models: The Boeing CompanyDC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd., Apple Creek, OH 44606		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST04605CH	Status: Current	App Date: 03/30/2022	Rev Date: 03/21/2023
Description: Installation of a Garmin GTS 8000 Traffic Alert and Collision Avoidance System (TCAS) II
TC Nos.: A-669
Models: The Boeing CompanyDC3C-R-1830-90C, DC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G
ACO: AIR-760: Central Certification Branch CHI

STC Holder: Preferred Improvements LLC 11234 Hackett Rd, Apple Creek, OH 44606, United States		If you are an STC Holder, Contact us to have your company added here!
STC No.: ST565CH	Status: Current	App Date: 09/09/1996	Rev Date: 03/09/2017
Description: Installation of a Fairchild F800 or F1000 digital flight data recorder.
TC Nos.: A-669
Models: The Boeing CompanyDC3C-S1C3G, DC3C-S4C4G, DC3C-SC3G, DC3D-R-1830-90C
ACO: AIR-760: Central Certification Branch CHI