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No reverse on 4


Juan
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Hi there,

During landing, it was a very smooth landing

- 4 engines to Flight Idle, 1000/1200 PSI each.

- 4 engines to Ground Idle, the torque is increased and no-reverse is experienced in four engines.

- The power cannot be lowered and the landing run is made with between 5000/6000 PSI (GI)

- Brakes are burnt

The blades never went to reverse pitch, is it possible that because of the smooth landing the touchdown relay was relieved during a short "flotation" period (1 or 2 seconds) and it prevented the four propellers from going to reverse angle..?

Juan

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  • 2 weeks later...

On the EPCS the backup solenoid is energized by the throttle position, lifting it up to come into the ground (beta) range. This is not normally tied into the touchdown electrical system. If the throttle cable breaks and takes the engine/propeller linkage to the reverse position the backup solenoid will not allow the blade angle to decrease below low pitch stop position as long as the throttle remains in the flight (alpha) range.

Vic

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On 12/9/2017 at 5:14 PM, pjvr99 said:

What aircraft model?

 

PJVR99,

it is a KC model, upgraded with EPCS

The problem was that none of the four propellers went to reverse and the FCU was still sending fuel, so below ground idle, the engines were still giving positive torque.

The beta lights went on, and also the no reverse lights, but apparently these illuminated after the throttle levers were in GI

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A system failure on all 4 props at once....you're talking probability numbers to the 20th or 30th decimal!  I would discount that possibility...or, go get a lottery ticket!  What was the aircraft speed when beta was selected?? And, what do you refer to by:

On ‎12‎/‎8‎/‎2017 at 1:32 PM, Juan said:

- 4 engines to Flight Idle, 1000/1200 PSI each.

 

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