Part# 11-09231
MFR Model# E-04R INT


The E-04 ELT is a direct replacement for the more than 62,000 model E-01 ELT's (by ACK) on the market today. The E-04 fits directly into the current E-01 mounting trays and uses the same remote control panel indicator. The E-04 external antenna will utilize your current antenna mounting and wiring installations.

Note: The installation manual for this item requires the installation of 2 very specific batteries for operation - Duracell part number PX28L or Eveready part number A55 (or equivalent) for installation into the switch assembly and Duracell part number CR2 or equivalent for installation into the audio alert indicator.

Retrofit Kit does not include remote

Warranty: All warranty issues must be handled directly with the manufacturer. These are non-returnable and non-refundable once installed. If any attempts have been made to install this unit it becomes a warranty issue and can only be resolved with the manufacturer directly. Please view the warranty tab for additional information on the manufacturer's warranty.
There is a $250 Recertification fee in addition to the 15% restock fee on all ACK products that have been opened.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • Accepts GPS position input data from Bendix/King. Garmin, Nema 0183 GPS
  • Antenna is swept back 20 degrees, and features a molded plastic base.
  • 5 watts @ 406MHz for 24 hours, and 100 Mw @ 121.5 MHz for 48 hours.
  • Simple plug in audible alert indicator.
  • Lithium battery pack offers a 5 year battery life, and makes it substantially lighter.


  • 7.75" long
  • 2.85" width
  • 2.85" height
  • 1.6 pounds in weight with battery
  • Remote requires a Duracell PX28L 6 volt lithium battery or an Eveready AS44 battery
  • Audible Alert Indicator requires a Duracell CR2 3 volt lithium battery or equivalent


  • 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

In The Box

New Install Version
  • E-04 121.5/406 MHz ELT
  • E-04.5 Remote with horizontal placard
  • E-04.12.2 Remote vertical placard
  • E-04.8 Whip antenna
  • E- Electrostatic discharger
  • E-04.10.4 Coax cable 60"
  • E-04.7 Audio alert
  • E-04.4 Mounting Tray
  • E-04.4.1 Retaining strap front
  • E-04.4.2 Retaining strap battery case
  • E-04.10.6 Female 4 pin DIN plug
  • E-04.10.5 15 foot remote cable
  • E-04.10.3 Audio alert cable
  • E-04.11.1 Switch cover
  • E-04M Installation/Operation/Manual
Retrofit Kit for ACK E-01
  • 121.5/406 MHz ELT
  • Remote horizontal placard
  • Remote vertical placard
  • Whip Antenna
  • Electrostatic Discharger
  • Audio Alert
  • Female 4 Pin Din Plug
  • Audio alert cable
  • Switch cover
  • Installation / Operation Manual

Note: If customer has ordered retro fit kit in error - they can order p/n: 11-15078 to make it regular ELT kit.


Ive installed 5 of these units so far over a few years. Units pass 91.207 inspections without problem. Installation is relatively simple although care must be taken to ensure proper battery polarity in the buzzer and RCPI. Wish the phone cable was a bit longer for installations in 172s but this can be worked around. Overall, the E-04 is my 406MHz ELT of choice.

Daniel J
October 13, 2021

Its an ELT that emits a signal just like all the rest. Compact size, easy to install, easy to test, easy to register and easy to buy. Im glad Spruce sells these A few negative comments focus on the batteries for the remote switch. Cross referencing the PL-28 which is a Duracell p/n, there are several options including 4LR44, PX28A, A544, 28PXA, 476A, 4G13, GP476, K28, V28, PX28AB, L1325, 1414A, V4034PX, PX28L, K28L, L544, L544BP, V28PXL, 2CR1/3N, 2CR1-3N, CR28L, 1406LC, 2CR11108. If you live near a pet store, these batteries are commonly used in shock collars for barking dogs.

David A
August 15, 2021

Easy install and works great took about 4 hours

John R
April 28, 2021

Great solution for converting the ACK E-01 to the ACK E-04 406 ELT..smooth easy plug in technology..quick sign off by my A&P , and it was done.

Scott S
April 26, 2021

Great service, always prompt, merchandise always well packed....

Barney L
April 6, 2021

showed up quick!!

Larry R
March 15, 2021

I havent really used this yet and I hope I never will. After all, it is an ELT. I purchased this to install in my Zenith 750 kit plane that I am building. It is easy to install, and from reports of others who influenced my purchase it is a really good product.

January 29, 2021

The unit is compact and well engineered .. easy to install and connect. The self test feature simplifies the requirements for testing and annual inspection requirements. This important feature makes this unit much simpler and less expensive to maintain than some other 406 MHz beacons.

Jeffrey J
December 26, 2020

While I known that you dont control shipping price, it is getting very expensive. Last order for 3 Elt an a few other small thing was north of $90...

Paul F
December 19, 2020

A very complete kit*, very well packaged and thought out, and the instruction booklet is well thought out, illustrated, and quite clear in the installation, registration, and operation. * Yeah, okay, you supply the attach hardware and a couple batteries if your want to install the remote panel and the party horn, but price out the competition, and their replacement batteries, and battery life, and youll see this unit gives the biggest buweeep-buweeep for the buck.

October 29, 2020


Please note, Aircraft Spruce'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. Aircraft Spruce 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: What is the difference between the USA and international version?

If you have a USA registered aircraft you will need a USA version (programmed for the USA). If you have an aircraft registered outside the USA you will need the international version in which we will need to know the country of registration so we can specifically program. You can fly any where in the world the key is programming to the country of aircraft registration.

Q: What is the difference between complete (new install) and retrofit kit?

If you have an ACK E-01 that you are replacing you can save some money and buy the retrofit kit as you already have parts installed that the E-04 will use. If you do not have an E-01 then you will need to buy the complete kit which will be a new installation.

Q: Does the ACK E-04 ELT transmit your GPS coordinates as well as 406?

By it self, no you will have to connect the E-04 to an external GPS to gain this feature. Refer to the manual for how to connect.

Q: How does an AP/AI test the unit at the annual condition inspection for proper function? Are there any special tools/equipment needed to test?

All of this is stated in the E-04 manual but a unit self test and checking lines for any corrosion is about all you need to do. No tools are needed and cost will only be the time to do the self test and check the lines.

Q: I'm interested in the ACK E-04 to replace a Narco 901 ELT, so I need the full installation kit. What else do I need in terms of panel indicators, etc. that are not in the package. Are there other required parts/special wire to connect to my Garmin panel GPS (530W)?

The E-04 is complete 11-06395 (For USA registered aircraft) for a new installation. For GPS connection you will need to refer to section 6 of the manual (on the Document Tab) which tells you what wire you will need based on your installation.

Q: On page 6, immediately above Figure 9, there is the statement connect the ELT RS 232 data and power to the aircraft systems. Is the ELT to be connected to Aircraft Power? I thought their power was independent from the aircraft.

In most cases yes the ELT is independent of aircraft power unless the manual state so and in this case is require if you add GPS information to the ELT.

Q: Does this ELT meet the requirements for the 406 required for Bahamas travel? With a new installation kit, is it approved for installation in the PA28-180?

The Ack 406/121.5 MHz E-04 ELT will meet the future Bahamas 406 Mhz Requirement and is approved for installation in a PA28-180.

Q: What is the battery replacement item for the ACK 406 E-04 ELT?

The replacement battery for the ACK 406 E-04 is part# 11-10012.

Q: What is included for a new installation?

The ACK 406/121.5 MHZ E-04 ELT comes with the ELT, Antenna, Remote Switch, Alert Buzzer and wiring.

Q: Is a whip antenna available for the AKC-406/121?

Yes, the Whip antenna for the ACK 406/121.5 MHZ ELT is P/N 11-10465.

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