737NG Simple Fault / PSEU- MCS

[B737NG_Pilot]

A single fault in certain redundant systems, or some simple faults, do not illuminate the MASTER CAUTION and system annunciator lights.

a) What are Simple Faults?

b) Do we have two types of PSEU?

Type 1 PSEU
The PSEU light and OVERHEAD system annunciator do not illuminate for simple faults unless a system annunciator panel is pushed for recall. In this case, a simple fault, resetting the MASTER CAUTION system extinguishes the PSEU light.


Type 2
The PSEU light, OVERHEAD system annunciator and Master Caution illuminate automatically for simple faults, but only after a landing. The PSEU light extinguishes when a parking brake is set or when both engines are turned off

[de facto]

a) What are Simple Faults?

The ones that should not make your captain scratch his head nor affect you when in the air.

[flyboyike]

1. Simple faults are ones that are not complicated.

2. Complicated faults are ones that are not simple.


Hope this helps.

[framer]

From our FCOM:

The PSEU, its sensors, and its input signals are monitored for internal faults. When designated faults are detected, a PSEU light on the aft overhead panel illuminates, and the OVERHEAD system annunciator light and MASTER CAUTION lights illuminate. The PSEU light can be reset following a maintenance BITE check or repair of the cause of the fault.

So I would say a simple fault is any fault that hasn't been "designated" and if it is a "designated " fault the bite test or rectification are needed to reset it.

[B737NG_Pilot]

How do simple faults differ in definition from single channel faults with relation to Master Caution System.?

Also are there two types of PSEU's ?

[Dynamite1]

Simple faults relate only to PSEU, wherein the PSEU Light and OVHD system annunciator do not illuminate for simple faults unless a system annunciator panel is pushed for recall. In this case, a simple fault, resetting the MC system extinguishes the PSEU light.
So all cases of MC on recall relate to single fault in redundant systems except the simple fault related to PSEU.
Yes there are two types of PSEUs.

[Tom!]

Simple faults relate only to PSEU, wherein the PSEU Light and OVHD system annunciator do not illuminate for simple faults unless a system annunciator panel is pushed for recall. In this case, a simple fault, resetting the MC system extinguishes the PSEU light.

On the newer ones we have the PSEU light automatically lights up 30 seconds after landing if a simple fault is present. Resetting the master caution system has no effect on the light. For a simple fault it extinguishes only when either the parking brake is set, or an engine shutdown.

[Dynamite1]

Indeed Tom; our fleet has a mixed bag of both.
737NG pilot.....tailwinds?

[B737NG_Pilot]

We too operate a mixed bag. Unfortunately I was not able to find info about the same, in the AMM. But I think I have got my question answered. Thank you people.