Agreed SAS, but some comments from other posters led me to believe that they were not aware how much different it is flying the 61 as opposed to a more modern twin. There is no one number that the Nr is expected to be sitting at on its own.
John: 721 C (-1) or 758 C (-2) are the maximum 2 1/2 minute T5's, so yes, all basically correct except the topping is achieved by limiting Ng. T5 and Q limits must not be exceeded when Ng is topped. During the check 2% Nr droop with the Ng steady at the limit (102.3/103.4) is used.
I disagree a little with the comment:
He knows that at 721, increasing collective produces no more power, and only results in Nr droop.
If the Ng hasn't topped yet (102.3/103.4 Ng), it will still spool up and provide more power, but the engine has been using in excess of t/o (5 min) power since passing 696 C and 100 Ng.
Again, the report won't open for me right now but I recall both Ng's were steady at 102 (102.3...???) as the Nr drooped. No T5 calls were made so we don't know.