Engine lockout use, a brief tutorial

[Diesel_Thunder]

Good day all,

Been seeing posts here about power lever use, and accidental activation of the lockout mode. So I put together a short video covering lockout use and an important setting in the special options menu that can get overlooked that can prevent pushing the power levers into lockout. Hope some of y'all find this useful.

 

Edited March 26, 2022 by Diesel_Thunder

[Frederf]

I can't get the fingerlifts to work as the CPG. I have pilot and CPG configured the same. My axis is power levers (both), special options fingerlifts enabled, and fingerlifts (both) up/down count to RCtl-PageUp. In the pilot seat while holding RCntl-PageUp I can move the levers freely beyond fly. In the CPG seat doing the same thing I can't.

[Diesel_Thunder]

2 hours ago, Frederf said:

I can't get the fingerlifts to work as the CPG. I have pilot and CPG configured the same. My axis is power levers (both), special options fingerlifts enabled, and fingerlifts (both) up/down count to RCtl-PageUp. In the pilot seat while holding RCntl-PageUp I can move the levers freely beyond fly. In the CPG seat doing the same thing I can't.

That could very well be a bug you found. AFAIK both sets of levers are supposed to do the exact same thing. 

[Frederf]

When lockout logic is selected how long does it persist and how is the logic deselected? You mention that the engine could shutoff in lockout for self preservation. What are the limits in fly logic and lockout logic?

[Diesel_Thunder]

Unfortunately, the DCS manual does not detail the operation of lockout beyond it's activation and use.

A manual that I presume to be the real one that I found on a quick web search went into a bit more detail (due to not wanting to violate any rules, I'm not posting a link). I'll paraphrase, but activating lockout is as described in the DCS manual and it disables (locks out) the Digital Electronic Controls from limiting/controlling functions except over speed protection. It also says to resume normal operation, that the power levers need to be moved to the idle position and then back to fly position.

From that description, I can only assume that once activated, the engines will remain in lockout until they are either shutdown, or one of the crew moves the levers to IDLE and then to FLY. Due to the requirement that the levers need to move to IDLE, I cannot fathom ever doing that in flight.

Once we can get more details from ED on the lockout functions, I plan on revising my video to include that.

As far as limits go, these are what I've put together from the DCS manual:

Turbine overspeed - Each engine has overspeed protection, and will shut down an engine if it exceeds 119.6 ±1% (the power turbine, or Np).

Turbine Gas Temperature - with both engines operating the maximum TGT allowed is 867°C for each engine. If an engine shuts down in flight, or one of the engines torque output falls below 51%, the remaining engine will go into single engine operation and automatically increase to the single engine TGT limit of 896°C. If the engines are in lockout, the temperatures are monitored and displayed on the ENG page, though if the temperature limits are exceeded, the DEC will not do anything about it as the only engine protection in this mode are the overspeed limits.

To summarize:

• Engine overspeed limit -- 119.6%
• Dual engine TGT limit --- 867°C
• Single engine TGT Limit - 896ºC

 

Edited March 28, 2022 by Diesel_Thunder

[Frederf]

OK, it locks out the temperature protections but the speed protections remain in place. That makes sense.

I would have guessed off to reset too but looks like idle is enough. Someone jockeying throttle manually would probably be midrange. One could possibly manage to dip to IDLE in flight long enough to reset (especially one at a time) but hard to imagine a situation. Perhaps inadvertent lockout engagement and/or misidentification of which throttle was needed to be locked out.

Is lockout recommended for SE flight or is it expected that SE one remains in fly range. Is lockout for failures or issues with the TGT limiting functions?

[Diesel_Thunder]

Lockout is more of an emergency use only. The DEC does a pretty good job of running the engines, whether it is dual or single engine ops (ham fisted pilots not withstanding ). I believe the intent is to be able to correct for a malfunctioning governor and be able to return to base. No reason to use lockout so long as the rotor RPM and engine speeds are stable. 

[bradmick]

Lockout is used when a “low side failure” is encountered in the aircraft. A low side failure is a failure where the engine is no longer producing its full power, this can result in a loss of Nr and an erroneous engine out audio (because the power lever is at fly and the NP on the failed engine is likely <94%). It’s during a situation like this when you lock out the engine and retard the power lever. Doing so disables the DECU and gives you full manual control of the engine. It should be noted that the engine is trimmed mechanically to maximum power but limited limited by the DECU. You never want to take the power levers to lockout unless the engine is failing to produce the power it should be. The power levers go to fly and stay in fly. If you accidentally do take them to lockout, the power lever has to go all the way back to idle to reset a micro switch in the power lever and re engage the DECU.