P178 Fail-Safe Audio Mixer

Your flexible, functional audio warning solution designed with the pilot and integrator in mind.

A versatile and flexible summing amplifier for airborne audio systems.

The P178 Fail-Safe Audio Mixer is an 8-input mixer providing 3 composite outputs. Channel 1 and Channel 2 Composite Outputs are Failsafe Relay Protected for Master Caution or Essential Tones to ensure that no fault in the system or an electrical bus failure can prevent pass through of Essential Warnings or Tones. Channels 3 through 8 are for non-essential tones and will drop offline in case of fault or Avionics Bus failure.

The P178 also removes the need for external relays, ensuring that essential tones are passed to unswitched inputs on any audio system. The unit also has internal fault detection. Upon fault, the relays go to their normally closed (Failsafe) position. The Fail-Safe Audio Mixer also has a pull low line on fault if an external fault indicator is desired.

  • 8-input mixer providing 3 composite outputs
  • Channel 1 and Channel 2 outputs are failsafe relays protected for master caution or essential tones
  • Removes the need for external relays

P178 Documents

AS350/AS355/EC130

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Bell 206 – 407

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Bell 204/205/212/214/412

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EC135

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EC145

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P178 Mechanical Specs
Height1.05″ [26.67 mm]
Width3.04″ [77.22 mm]
Length5.75″ [146.05 mm]
Weight0.50 lbs [0.23 kg]
FAA/ PMA STC SR02445SEAS350B, BA, B1, B2, C, D, D1. AS355E, F, F1, F2. EC130B4, T2.
EC-135P1, P2, P2+, T1, T2, T2+.
BO-105A, C, LS A-1, LS A-3, S.
Bell 206A, A-1, B, L, L-1, L-3, L-4. Bell 407.
FAA/ PMA STC SR02444SEMBB-117 (EC145) A-1, A-3, A-4, B-1, B-2, C-1, C-2, D-2.
Bell 212, 412, 412EP, 412CF, 204B, 205A-1, B, 214B, B-1, 214ST.
Canada STC SH-09-17AS350B, BA, B1, B2, C, D, D1. AS355E, F, F1, F2.
BO-105A, C, LS A-1, LS A-3, S.
Bell 206A, A-1, B, L, L-1, L-3, L-4. Bell 407.
Canada STC SH-14-33EC-135P1, P2, P2+, T1, T2, T2+.
BO-105A, C, S.
Bell 206A, A-1, B, L, L-1, L-3, L-4. Bell 407.
AS350B, BA, B1, B2, C, D, D1. EC130B4, T2.
AS355E, F, F1, F2, N, NP.
EASA STC 10036806AS350B, BA, B1, B2, C, D, D1. AS355E, F, F1, F2. EC130B4, T2.
EC-135P1, P2, P2+, T1, T2, T2+.
BO-105A, C, LS A-1, LS A-3, S.
Bell 206A, A-1, B, L, L-1, L-3, L-4. Bell 407.
Brazil CHST 2007S06-30AS350B, BA, B1, B2, C, D, D1. AS355E, F, F1, F2. EC130B4, T2.
EC-135P1, P2, P2+, T1, T2, T2+.
BO-105A, C, LS A-1, LS A-3, S.
Bell 206A, A-1, B, L, L-1, L-3, L-4. Bell 407.
MBB-117 (EC145) A-1, A-3, A-4, B-1, B-2, C-1, C-2, D-2.
Bell 212, 412, 412EP, 412CF, 204B, 205A-1, B, 214B, B-1, 214ST.

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