W&B for DAR inspection

Hi Folks,

I am working out the numbers for the DAR inspection and it seems that I need to submit W&B for at least three scenarios:

1) Most Aft CG
2) Most Fwd CG
3) Flight test CG

The FAA provides pretty strict guidance on what to use for pilot/passenger weight (170 lbs), and how to compute minimum fuel (1/12 of the HP).

My problem is that when I use these numbers and maximize the weight for the baggages (50 lbs Aft floor, 25 lbs Aft Shelf) according to the design limit, my most Aft CG is out of limits by just a little bit.

How do I address this? Do I simply reduce the baggage weight till I get under the limit?

Any guidance will be helpful.

Thanks,
Ashish

Yes.

The objective isto help you understand how you should and should not load the airplane in order to safely stay within the designed CG envelope.
It is not uncommon to NOT be able to load the aircraft in all conditions and remain within the envelope. It is especially important to pay attention to the CG at landing at the END of the flight, because it will change as you burn off fuel.

Vic

vic syracuse said:

It is especially important to pay attention to the CG at landing at the END of the flight, because it will change as you burn off fuel.

Vic

Click to expand...

YES!!

Read and understand this.

The 10 can be loaded so that it goes out of CG aft with really low tanks. I suspect the 8 may also, just part of having front and rear seats, and baggage behind the seats.

Paperwork issue ..

Thanks for the responses. I do fully agree with the objective and the idea to look at the CG as fuel burns off.

My question, however, is more about the paperwork.

When I present this form to MIDO/DAR is it ok to use the reduced baggage weight, so that my cg is within limits? I am worried that MIDO/DAR would reject that calculation stating that I did not use max baggage limit. Anyone encountered this issue?

No, it's the other way around.
They want to be sure YOU are aware of the limits of your aircraft. If the aircraft is built with a certain CG, they want to be sure you know it and are capable of loading it correctly.
You should have an example of a forward CG limit condition, an aft CG limit condition, and your planned first flight CG.
RV-4s & RV-8s are W&B challenged because they are piloted from the front seat for the maximum pleasure of the pilot. Adding a passenger and rear baggage moves the CG aft, so it is not unusual to exceed the rear CG before you reach gross weight with a passenger and some baggage.
They want to see an example of full legal aft CG at landing (after fuel has burned off and CG has moved aft, even as the plane got lighter).
An other point: you would like to make you first flight with the CG 1/3 of the way aft of the most forward CG limit. My RV-8 flies perfectly at this CG, and Andy Karmy has recently stated the same. You may as well make your first flight with everything in your favor.

Airzen said:

Thanks for the responses. I do fully agree with the objective and the idea to look at the CG as fuel burns off.

My question, however, is more about the paperwork.

When I present this form to MIDO/DAR is it ok to use the reduced baggage weight, so that my cg is within limits? I am worried that MIDO/DAR would reject that calculation stating that I did not use max baggage limit. Anyone encountered this issue?

Click to expand...

Yes you are on the right track. Put numbers in that work with the 170lbs people weight. Make them what ever works and you will be fine with the DAR.