PPRuNe Forums - View Single Post - engine parameters log difference
View Single Post
Old 3rd November 2022 | 18:19
  #4 (permalink)  
RVDT
15 Anniversary
 
Joined: Nov 2006
Posts: 1,951
Likes: 90
From: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
Doesn't look that unusual.

There can be issues with "rounding errors" in the way the airframe display looks at partial cycles which can accumulate versus the way the DCU counts.
The "algorithm" in the EEC does take into account the time between start and fly amongst other parameters. EMS "fast starts" will eat cycles more.
DCU record is written to the EEC on boot and at end of flight calculated and written back to the DCU. The "write" occurs at a particular N1 speed and on early 206's it was set too low for the folks that turn the battery off before the N1 had stopped and would corrupt the data. All fixed these days.

If you are really keen I think the algorithm might be in the EMM.

IM = Impeller
CT = Compressor Turbine
PT = Power Turbine

"Training Mode" - during the introduction of the EC135P2 with the PWC 207 (206B2) there was a period where the switch controls for "TRAINING MODE" were fitted but not the software or wiring. It was placarded as INOP or maybe not.
i.e. Factory training carried out with new customer and as the customer was unfamiliar and the training pilot was possibly too complacent TRAINING selected but not confirmed with Delta with "T" and TRAIN IDLE on the CPDS display and cross checking digital values remain similar. Training continues until after a few flights ENG EXCEED warning. Turns out they were using real OEI limits! Two new engines before handover to the customer.

This was also the period before the flight stops were fitted to the twist grips on the EC135 to keep them from being rotated out of the N detent. Last thing a lot of pilots from "old style" machines do is check the throttles are both OPEN. i.e. Bell 212/412. Result - both engines revert to MANUAL and do as requested. OVERSPEED.

Don't get in a position in TRAINiNG MODE where the OEI N1 tops out and Nr droops to where it initiates "recovery" back to normal as you will easily get a torque exceedance. Being above OEI training weight limits contributes.
RVDT is offline  
Reply