Power check technique for twin turbines
 

I use this method:

Slow airspeed just above TL (usually around 40 knots, just before she starts to "shudder").
VSI zero
Ball centered
Crossing the area on a pre-determined heading

Then check:
Airspeed vs GS
Pitch setting vs power indicated
Track vs Heading

On the speeds, I can see exactly if I have estimated the winds at the area correctly.

Pitch setting vs power when VSI is zero shows me the same, plus I can read what my estimated power on landing will be (usually Power indicated pus 8-10 percent).

Track vs heading is all about the drift in case of wind again...

At unknown landing sites, I usually do a high recce, then a low recce including the power check, where I also check landing site elevation, last check for obstacles and approach path..

Two different things. One is for engine health the other a rule of thumb for calculating powerrequirement for a given situation.

skadi

:ok:
Thanks, pic was nearly unreadable on mobile phone..

skadi

Use the RFM before you fly to check you have at least OGE power available at the expected temp/pressure/AUM at the LS.

Then deduct 5 or 10% of the MAUM indicated by the graphs - that will give you a thrust margin.

Finally do an in-flight power check within 5nm/500' of your LS to confirm you can get max power.

Land safely taking into consideration local wind effects.

FB - your screenshot shows the same AUM calculated for AEO HIGE, AEO HOGE and Cat A VTOL - there should surely be a difference if it is about performance unless that 3650 Kg is at the edge of the graph?

The one in good quality is a sample picture - which doesn´t really mean, all the figures must be correct - its just showing, where you find which information.

The screenshot with the low quality gives the correct numbers, which were for the time - Summer, 200 feet AMSL
Total weight 3078 kg
AEO HIGE 3700 kg (MTOW)
AEO HOGE 3700 kg (MTOW)
CAT A VTOL 3603 kg
OEI 30s HOGE 3378 kg
OEI 2min HOGE 3039 kg - amber - not yet possible

Thanks FB - that makes much more sense :ok:

Your “power check” appears to be a “rule-of-thumb.” And as such, it’s not intended to be strictly accurate or reliable for every situation. For example. Imagine flying at a density altitude where the power required for 25 knots is nearly the maximum power available. In that situation, HIGE and HOGE would probably be impossible. A HIGE/HOGE determination has 3 components, power required, power available and power assurance. Therefore, your “rule-of-thumb” really isn’t a “power check”.

It’s all on the screen (AS-350 VEMD shown):
https://cimg6.ibsrv.net/gimg/pprune....87b3a42d67.jpg

Fly a Chinook....

Power.... Check....plenty of it...

I drooped the Rotor RPM so low on an early "A" Model Chinook....the Generators dropped off line.

That was an interesting takeoff!

All that is a paperwork exercise conducted before even getting into a helicopter-and therefor useless when actually flying...


The question was about a check when flying......

And the deal is:
Will I have enough power available with the fuel/load, temperature, altitude and space available I have NOW, and will I be able to take-off again?

There is no chart for that (unless in the military, flying with a crew of 3, 4 or more, where one has enough time and staff on hand to read through all that crap while doing your recce).

The majority of us Utility pilots fly single pilot, and have to fly in rough terrain.


That's where our "rules of thumb" come in handy...

So you don't really know your AUM when you are flying then?

Surely you must have an idea of the likely pressure and temp you will be flying in during your day and can work out a best case and worst case scenario based on fuel and load?

Remember the seven Ps:ok:

Crab,some of us are reminded about those every night....!!

If you are flying in mountainous terrain, you will not know all details......

You will be able to calculate your weight at the time of arrival, but that's about it.

Wind situation up there is unpredictable, and so is the temperature.

Same with unknown LZ in the rain forest.... You don't even know the exact location-sometimes you just have a coordinate, and you know the recce team will be on the ground within a few km radius of that coordinate.

Now tell me how you are doing your calculations before the flight?

Especially in remote areas, with no weather forecast or reporting station within 1000 nm?


That's why Offshore pilots are usually unprepared when coming into the Utility world, as they are used to much better service around them... (let's not get into a debate about it again, Utility pilots getting into the Offshore world also struggle...)..