Man that sucks. We cruise the 1900 at 780 degrees as long as the overspeed isn't going off.
The thing about cruise power is that the engine is well cooled by the fast moving air. As long as you are with in limits, the engine will show very little wear. The only time you are actually doing any significant wear and tear on the engine is during start and take off. Both of those incidents occur with relatively little air flow over the engine with the EGT/ITT up to limits.
If you do my cruise power settings like Dirtybeech outlined you'll fly at or around 610 deg EGT below 15,000 and creep up toward 650 by FL250. The best thing for everyone in the AMF SA227 fleet to do is to right down specific fuel burns v ground speed each flight and forward it to EM and SK.
If you do that you'll be able to document the fuel lost on those legs. Just show your lbs/nm burn. You should be able to get 2.5 lbs/nm
+ 0.5 depending on wind. Example:
14,000
Power Setting-lbs/hr-gnd speed-lbs/nm
Company 580 600/200/3.0
Old Power 610 620/215/2.9
LRC (as above) 625/220/2.8
I don't have any of the actual numbers I documented in flight in front of me. However, those are pretty representative of the actual numbers you'll get. LRC (long range cruise) will just barely beat out 610 every time and 580 will only beat 610 if you are at really low altitudes like 5,000.
Besides being less fuel efficient, 580 also creates extra maintenance. If you have a route that is taking about 1 hour of flight time per day on the 610 power setting, you'll probably take 1.1 hours to complete it at 580. That means timed maintenance items like letter checks that come up every 100 hours or so will occur with fewer legs flown.
So, if you had been flying for 1 hour per leg and are now flying 1.1 hours per leg you'll have to have a 100 hour inspection done every 90 legs rather than every 100 legs. If you are getting X amount of dollars per leg (which AMF is in some cases) than you have fewer funds to pay for that maintenance.
I've told everyone in DFW this, and most agree. If you need a procedure for an aircraft, chances are someone somewhere has already researched it, done it, documented it and published it for our edification. If you want to save gas and be more efficient, look up the numbers in the AFM. They aren't straight forward, but they are there. You just have to convert TAS to IAS and you'll have all the info you need.