F-16 ICS Drop-In Replacement

The Terma digital intercom system can substitute the legacy ICS on F-16 aircraft.


Terma's Aircraft Audio Management System (AAMS) is a major technology upgrade of the legacy aircraft intercom system. It utilizes the latest audio technologies in digital signal processing to improve the basic intercom functionality and to add capabilities not previously used in cockpits. All existing F-16 versions (up to and including block 52) use the same legacy analog intercom system and will all benefit from being upgraded with the Terma AAMS, which is the only fully qualified and combat proven alternative available on the market. 

Digital Intercom Amplifier with embedded 3D-Audio software. Earcups with embedded Active Noise Reduction, applicable for all F-16 blocks up to and including block 52.


Terma’s digital Aircraft Audio Management System (AAMS) offers a range of benefits which include:

  • Reduced workload
  • Improved situational awareness and survivability
  • Reduced hearing loss and fatigue
  • Improved speech intelligibility and flight safety.

For a detailed description of those benefits, refer to “Aircraft Audio Upgrades

LRUs are in Production
All Line Replaceable Units (LRUs) required to perform an upgrade on any F-16 are fully qualified and in full-scale production. This means that an update program can be established without a comprehensive development program and without the risk typically associated with development.

Simple Aircraft Modification
The effort involved with replacing the old analog system with the AAMS is limited. No major Group-A changes are required; only the existing Interphone Amplifier and corresponding Filter Assembly need to be taken out and replaced with the Terma manufactured Mounting Base and corresponding Enhanced Interphone Amplifier. Minor changes need to be incorporated in the Communication Matrix Assembly, and the earcup part of the helmet need to be substituted with the Terma ANR enabled headset.

Backwards Compatibility with both Aircraft and Helmets
AAMS is designed with backwards compatibility to allow a smooth migration through the upgrade. Pilots wearing upgraded helmets (Terma ANR enabled headset) remain compatible with legacy aircraft, and at the same time, pilots with legacy helmets remain compatible with upgraded aircraft (upgraded with the Enhanced Interphone Amplifier (EIA)). This is achieved by including the old analog capabilities in both EIA and headset and enabling the digital mode of operation only when both helmet and aircraft is detected as being the upgraded versions.

Redundant ICS
Redundancy is a derivative advantage of this implementation. In case of failure to the digital electronics, the AAMS will revert to a fall-back mode, where the analog ICS capabilities are retained.

Users are Thrilled with the System
The significant improvements resulting from the digital AAMS to the audio environment are best illustrated by the quotes from current users:

  • "It is very intuitive to receive an audio warning from the correct direction and elevation. This allows me to immediately look for the threat on the right line of sight, saving valuable seconds"
  • "ANR removes the annoying, low-frequency rumbling of the engine and other aircraft noise".

As also implied by the user quotes, the system is combat proven. It was installed on the Danish F-16s which were deployed for 7 months in the mission over Libya.


The AAMS solution, when implemented in the least interfering form (i.e. with minimum changes to aircraft Group-A and no core changes at all) provides three major operational benefits:

  • 3D-Audio and Radio Separation
  • Active Noise Reduction (ANR)
  • Electrical Noise Reduction (ENR).

Reduce the Dominant Cockpit Noise
The ANR is optimized to suppress the acoustical noise which is generated by the Environmental Control System (ECS) in the F-16 cockpit. The ECS is, with up to 70 %, by far the largest contributor to the cockpit noise environment, although one might expect the engine or the exterior wind noise at high velocity to be dominant.

Eliminate Electrical Noise
ENR is also optimized towards the F-16 legacy design, where 400 Hz and higher harmonics are induced into the various audio signal paths and appear in the pilots headset as a "tone" which can vary in amplitude from noticeable to, in some aircraft, very annoying. In the Danish F-16s, this has been identified by “Arbejdstilsynet” (Danish version of Occupational Safety & Health Administration) as a potential risk for hearing damage, but was resolved by the Terma ENR solution. The ENR technology is capable of eliminating the “tones” without compromising the speech intelligibility and safety aspects.

The actual aircraft group-A modification required is shown in detail for an F-16B and an F-16D in the file below - the A and C mods respectively are subsets hereof. 

Only Minor Aircraft Changes are Required
As can be seen from the pdf, a few cuts and splices are required within the Communication Matrix Assembly. Those are needed in order to separate the audio from the two radios all the way to the EIA (allow the EIA to know which is the source), and to also allow the EIA to sense which radio is being keyed. 

Interface Available for Additional Capabilities
If additional integration is desired, a serial data communication channel is available to the EIA, through which commands and status can be communicated. This includes integration with e.g. a head tracker, integration with the aircraft Electronic Warfare suite for presentation of threat information as 3D-Audio cues, and to distribute commands which are received and interpreted by the Voice Recognition SW module within the EIA.