PPRuNe Forums - View Single Post - Sikorsky S-76: Ask Nick Lappos
View Single Post
Old 8th Oct 2009, 05:43
  #1117 (permalink)  
bb in ca
 
Join Date: Apr 2004
Location: NO GPS FIX
Posts: 133
Received 0 Likes on 0 Posts
In my opinion you are limited by the stated Limitations in the RFM. Transient limits are not to be planned for. Soft limiting is beyond the limitations and are transients.

I do use soft limiting and I don't think it's a bad thing BUT it's not planned for or routinely used. The 76 C+ and C++ are not easy to finesse to take-off power limits and occasionally soft limiting is used.

Limitations Section - C++

OPERATING CONDITION Take Off
TRANSMISSION TORQUE LIMIT (%) 100
%N1 100.0

POWER ON
Maximum: 108% Nr; except 109% transient operation for 20 seconds
Minimum: 106% Nr (dual-engine operation)

NOTE
Operation above 104% torque, 100.5% N1, or 912°C T5 is reserved for actual emergencies, inadvertent transient excursions, or, as artificially biased indications, with the OEI training provision.

I think the note is there to allow for use of the soft-limiting without penalty. Notes are not limitations but notes.


A whole other subject would be why are pilots taking-off with weights that aren't right for the a/c with the present conditions.

Just my opinion

Fly safe,
bb
bb in ca is offline