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90-Day Beacon Underwater Locator Device

Product overview

With requirements for aircraft to meet more stringent guidelines for underwater beacon operations, L3Harris responded with its 90-Day Beacon upgrade. This solution provides a more capable, certified underwater locating beacon for all L3Harris Cockpit Voice and Flight Data Recorders. The 90-Day Beacon is a long-life battery-operated underwater acoustic pulse generator (beacon/pinger) that is activated when the water switch is immersed in either fresh or salt water. The standard for beacons, as defined in TSO-C121B, calls for beacons to operate for a minimum of 90 days, upgraded from 30-days. Factory-approved L3Harris 90-Day Beacon retrofit kits help improve the traceability and performance of your L3Harris recorders.

  • Triples the guaranteed uninterrupted operation life of current beacons once activated
  • Exceeds all requirements of FAA TSO-C121b and SAE 8045A
  • Easily mounts to existing L3Harris voice and flight data recorders

Key Features

Creating an industry standard

As the aviation industry moved towards longer beacon standards, L3Harris introduced the 90-day Beacon in 2015 to meet these demands. Additionally, L3Harris has made a commitment to provide upgrade kits that are in accordance with the 90-day beacon mandate, allowing operators to remain in factory Component Maintenance Manual (CMM) compliance as they upgrade their fielded recorders.


Designed to perform, built to survive

The 6.7-ounce aluminum-cased L3Harris 90-Day Beacon is watertight, and capable of operating at depths of 20,000 feet (6,096 meters) and has a direction range of 2,000 to 4,000 yards (1,800 to 3,500 meters) depending on environmental factors. It is built to withstand a sustained pressure of up to 8,700 psi.


Easy to maintain

The L3Harris 90-Day Beacon requires a routine maintenance check every two years as outlined in the L3Harris Component Maintenance Manual (CMM). Its long-life battery should be replaced every six years.

Product specifications

  • Water-tight aluminum case 1.3 in. diameter (3.3 cm)/3.92 in. length (9.95 cm)
  • Capable of operating at depths of 20,000 ft. (6,096 m)
  • Detection range of 1,800 to 3,600 meters (2,000 to 4,000 yards) depending on environmental factors
  • Built to withstand a sustained pressure of up to 8,700 psi
  • Weighs 6.7 ounces
  • Water switch actuation initiates beacon operation post submersion in either fresh or salt water
  • Sustained operation > 90 days
  • 160dB at a frequency of 37.5 KHz
  • 10 ms pulse occurring once per second
  • 2-year routine maintenance check as outlined in L3Harris Component Maintenance Manual (CMM)
  • 6-year battery replacement

L3Harris Aviation Recorder Family

90-Day Beacon Retrofit Kit

Content Description

Standard Product


L3Harris-approved retrofit kit for standard products (kit comes with an L3Harris Service Bulletin enabling the conversion and Manufacturing Inspection District Office (MIDO)-approved installation instructions)

Legacy Products


L3Harris-approved retrofit kit for legacy products (kit comes with an L3Harris Service Bulletin enabling the conversion and MIDO-approved installation instructions)

(Tactical Recorders)


L3Harris-approved retrofit kit for SRVIVR products (kit comes with an L3Harris Service Bulletin enabling the conversion and MIDO-approved installation instructions)

  • 90-Day Battery Replacement Kit: P/N 147-E5542-00
  • 30-Day Battery Replacement Kit: P/N 147-E0305-00
COMPANY CERTIFICATION ISO 9001:2008 and AS9100:2009 Rev. C Certified

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Visit Technical Support Website

To gain access to the latest technical publications, service bulletins and other pertinent information about your recorders or other L3Harris devices, operators and authorized repair facilities need to register with our technical support organization for the online library.

Technical support:
Phone & AOG hotline: +1 (321) 674-4900

Technical publications:

Cage Code / Federal Supply Code: 25583

Facility / Shipping / Mailing address:
5353 52nd Street, S.E.
Grand Rapids, MI 49512-9704 USA

Order administration / Sales / General inquiries:
Phone: +1 (616) 949-6600

Repair and overhaul administration: 
Phone: +1 (321) 674-4900
Fax: +1 (616) 977-6895
For service repair (Part 145) returned material authorizations (RMA): Visit RMA website

Data services:

Frequently Asked Questions