Thanks for the entry Diego.
Good find.... and I hope this is the end of the problem.

Oct-23-2026
A 767 with a long history of intermittent faults:
Flickering lights on different occasions.

Pitot heat Korry Switch lights 
Flt data Recorder off light
Equipment Cooling Valve light
F/O air speed V1 and AOA on flat screen 


Since December 2025 has been a problem
multiple entries and replacement of equipment and harness 
PSEU unit accusing always sensor S267 R/H MLG
computer will switch from far to near  causing the lights flickering. 

On the Fwd E/E behind the EICAS computers, probably from the a last MOD found 3 clamps pinching wires on a big bundle. This problem has caused multiple AOG and money loss to the company.
Hours of T/S and man power unknown.







 

I have used a Megger on engine loops, but I'm not a fan of using one.

A Systron loop is pressure filled, so a Megger shouldn't hurt it. The Kidde???? I would stay away from a Megger.

With this problem, after we used the decade box for substitution, the loop read 30MΩ (that was just from removing the one terminal lug).

We smacked the white doughnut pretty hard and the 4.5KΩ returned. It didn't fail after the beating.

I use a regular VOM on most engines loops. A LCR Meter can also be used.

A LCR Meter should "always" be used on body and wing overheat loops.
  
     
 

Mark did you try to test the loop with a megger once removed? I remember it being a way to find intermittent loop failures but blurb in the manual that the loop must be clean prior to using the megger.

767 with a hard fail on the left engine EEC (Electronic Engine Control).

Engines with a EEC have a mechanical fuel control. FADEC (Full Authority Digital Control) engines have a HMU (Hydromechanical Unit) to control fuel.

Either way, the EEC or FADEC require external inputs to assure proper engine functions.
  
     

With this problem, the EEC's were swapped between engines. The problem didn't follow.

We put a meter to all external inputs and measured the torque coils and feedback wires to the fuel control.

We found the T1.2 temperature sensor reading open. We verified the wires to the sensor plug were good. Resistance readings directly at the probe still had the open.

After a replacement sensor was obtained, we checked resistance. It read 220Ω.
  
     
  
After the replacement and engine run..... all EEC functions checked normal.
  
     

Interesting problem today. The right engine loop 1 was showing as failed on EICAS. The system installed was a Systron-Donner.

We disconnected the pylon plug and checked the total loop resistance 1.5KΩ, this is a good reading.

Moving to the...