ACK A-30.5 Altitude Encoder FAA TSO

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Part# 11-01561
MFR Model# A-30.5


Add Mode C capability to your aircraft the most cost-effective way. The ACK encoder features the latest solid-state electronics for high reliablity. Installation is quick and easy and usually is completed in less than one hour. It is compatible with most transponders in use today and reports altitude to 30,750 ft. Includes quick-release mounting try, 4-ft. color-coded wiring harness with prewired jack, static line and fittings for installation in any aircraft, and installation manual in any aircraft, and installation manual with popular transponder pin-outs. 3 year warranty.

Quick Release Mounting Tray
4 Foot Harness
4 Foot Static Line
Installation Manual
Three Year Guarantee

California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • High Quality Construction
  • Gold Plated Connectors
  • Diecast Aluminium Chassis
  • Anodized


  • Approvals: FAA TSO C-88a
  • German LBA 10.221/4
  • Range: MOD 5 950 to 30,750 feet /w gray code Output
  • Accuracy: Typical +- 20 feet Maximum +- 50 feet
  • Size: L 6 W 2.65 H 1.3
  • Weight: 5.1 oz (144 grams)
  • Operating voltage: 10 to 32 VDC
  • Operating current: 60 mA typical
  • Operating temp: -4 to +131 F -20 to +55 C
  • Warm-up current draw: 14VDC 420 mA 28VDC 220 mA
  • Warm-up time: 70 F ambient 60 seconds 0 F ambient 210 seconds
  • Altitude resolution: Gray code (parallel) output 100ft


  • Avionics products manufactured by ACK Technologies, Inc. are warrantied against defects in materials and workmanship for a period of three years from their manufacture date. This warranty is limited exclusively to repair or replacement of the E-04 ELT and associated parts which were manufactured by ACK Technologies, Inc. the defective parts must be returned freight prepaid to our manufacturing facility. This warranty does not include repair or replacement of any part that has been improperly used, installed or physically damaged. This warranty does not cover any damage caused by chemical exposure. Discharge of the ELT lithium battery is not covered by this or any other warranty. Except as provided herein ACK Technologies, Inc. makes no express warranties, and any implemented warranty of merchantability of fitness for a particular purpose is limited in its duration to the duration of the written limited warranties set forth herein. ACK Technologies, Inc. shall not be liable for any direct, indirect, special or consequential damages arising from the use or misuse of this product. Except as provided herein no employee, agent, dealer, or other person is authorized to give any warranties of any nature on behalf of ACK Technologies, Inc. YOU MAY HAVE ADDITIONAL LEGAL RIGHTS WHICH VARY FROM STATE TO STATE


Reasonable price and works as advertised.

John A Verified Purchase


February 28, 2024

As described.

Greg M Verified Purchase


October 21, 2023

Mohamed A Verified Purchase


August 14, 2022

Arrived in 10 days to Italy, perfectly working to replace my broken one Thanks

Gianpaolo C Verified Purchase


April 20, 2022

would buy again

Paul C Verified Purchase


September 24, 2021

purchased this to replace the new AmerKing AK350 (FAA withdrew TSO Mar 2016). This product also previously used for years in my aerobatic experimental. Small , lightweight, easy to integrate. Mark Y

Mark Y Verified Purchase


August 26, 2021

MIst informent on model to buy from ACK

Luc R Verified Purchase


June 10, 2021

Looks like it will work ok

Richard S
April 2, 2021

Order fulfilled and delivered as promised.

Dave S
January 21, 2021

Easy to install and works as advertised!!!

John A
September 15, 2020


Please note,'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: I have an SL70 UPS Aviation transponder that can digitally read out altitude that it is transmitting to ATC. Will this encoder provide that capability to the transponder display?

Per Garmin the ACK encoder with give the SL 70 altitude information on the display.

Q: Is the ACK A-30.5 encoder compatible with the Becker BXP 6401-2-(01) transponder?

Yes, the ACK A-30.5 is compatible.

Q: Is the ACK A-30.5 compatible with the Becker ATC 4401 transponder?

Yes the ACK A-30.5 will work with the Becker transponder.

Q: Is the ACK A-30 compatible with Narco AT50A TSO transponder? What else is in the box?

Yes, the ACK can work with the Narco AT 50A. In the manual shows the wire diagram. In the box is a 4 foot harness, 4 foot pitot-static line, installation hardware and the installation manual.

Q: Will the ACK-30.5 Altitude Encoder work with a king KT76A?

Per the manual for the ACK-30.5 Altitude Encoder, they do give the wiring diagram for the King KT76A.

Q: Is the ACK A-30.5 encoder compatible with the KT76C transponder?

Per the Manual, The ACK A-30.5 is compatible with the KT76C.

Q: I have an Ack 30. Will this replace it without a harness change?

Per the Manual, The Ack 30.5 is plug compatible with all earlier Ack 30 models.

Q: Is the ACK A30.5 compatible to the Garmin GTX 328?

Yes, the A30.5 is compatible with the GTX 328.

Q: Is the ACK A-30.5 altitude encoder compatible with Garmin 155XL?

Yes, they are compatible.

Q: Is the ACK A-30.5 compatible with GARMIN GTX 335 transponder?

Yes, this will work with the Garmin GTX 335. Garmin also makes an encoder which plugs into the back of the transponder, which can be found under part number 11-14162.