Aft of CG Limits

[4thethrill]

First time posting here so y'all go easy. I'm hoping to get a real world answer for someone who just broke into it. Have any one of you veterans ever had to fly out of the aft CG limits prior to picking up passengers and also dropping them off? This is the first time I've encountered an R44 RII with a longitudinal CG of 107.2 so with my light butt I'm out even without fuel. BTW-Picking up and dropping off passengers in two different spots so ballast either needs to be creative or nonexistent. Weight is an issue with full passengers and all the fuel is needed. Thanks for the helpful replies!

[Boudreaux Bob]

Alouette III's with Sand Filters had a very aft CG.

We carried a Sand Bag for ballast. Once loaded with passengers you can always empty the sand and the bag weighs naught.

[Arm out the window]

Or a water jerry can.

[helopat]

Yep, concur. Carry sandbags or jerries full of water. If you can't carry them back due to weight, dump out the sand or the water and you're golden.

[Ascend Charlie]

Have any one of you veterans ever had to fly out of the aft CG limits prior to picking up passengers and also dropping them off?

Don't ever attempt to fly if you calculate you will be out of limits. Limits are imposed for a reason. You will make your insurance cover invalid, the maintenance release may also be invalid, and all sorts of people will want to jump on your head.

Get a different machine is the best choice. If not, the AUW with your planned pax and the normal chubby pilot for that machine must still be OK, so carry enough weight to bring yourself into limits. If that will then put you over weight for the passengers, don't do the job or get skinny passengers.

[4thethrill]

Thanks for all the replies everyone; I really didn't want to attempt out of limits so it helps hearing from you all. Water it is.

[topendtorque]

Being out even with fixed reserve of say 30 minutes is an issue. Survival gear can be played with a bit or a pet rock under the rear seat with pax and at front of cab without pax. If you are somewhere that you can't pick up water or sand or it's rather strange to the pax for you to be loading sand etc after drop off with only say half hour out of full.

Very good to see you worried about it, I suggest you spend some time talking with the A&P weight specialist and senior pilot on the job and do quite a few sums, it seems a bit far back to me.

I always set up these and the KH4's with CofG right at rear margin with full fuel and reasonably light pilot, making sure they all knew how much ballast to carry and where, cos when that fuel gets low with a full cab and the cyclic is right aft you need to make sure you have enough to flare if need be.

You could always carry a few pet rocks out to each fixed location for use when required.

As AC says keep it legal having someone jump all over yer head is an ugly scene, in this country at least.

[rotorfossil]

Some R44's have the battery in front of the instrument panel which fixes the aft CofG problem, but for us heavier gentleman gives a forward CofG case with two heavy people in the front. Can't win!

[Boudreaux Bob]

I always preferred the Aircraft to be Tail Heavy as that gives some assistance should you ever shuck a Tail Rotor/Gearbox for some reason. If you are on the forward limit and and encountered that problem you would really be in trouble.

Not that I rode around waiting for that to happen but after seeing a few cast iron failures on Bell products it did bear some consideration.

[topendtorque]

Minimum solo pilot plus forward baggage weight with all
doors installed is 150 Ibs (68 kg) unless a weight and
balance computation shows CG is within limits. Ballast
may be required.

From the limitations section.

BB I too carry that phobia around with me, but never been game to really do the crunchy numbers on how much of that thaing could depart and still be able to do something about it.
cheers tet.

[Arrrj]

TET,

For me, all of this is a good enough reason to keep my weight at around 88 kg...by the addition of a few beers when required !:ok:

Arrrj

PS _ in my experience it is really hard to get a 44 out of CG, but (of course) quite easy to be over MAUW if you are not careful.

[Ascend Charlie]

For those of you who think they can fly away from a failure involving the departure of the tail rotor gearbox...... you are kidding yourselves.

Look at Youchoob at any event where the rotor tip hits something - first thing that follows is the tail boom snapping off, fuselage rotates, all deady-bones.

In August 1981 at Williamtown, a B-model Huey had a weird failure where one T/R blade hit the fin, broke off, the imbalance tore the whole gearbox out, the change of cg made the nose drop and yaw but the disc stayed where it was, mast bump, rotor separation, tail boom chopped off, blade passed through front cabin (very messy) and the whole lot dropped upside down from 1500' into a swamp.

Don't even consider playing with the CG "just in case the gearbox falls out". Keep it in limits all the time.

[topendtorque]

Yes as I said - a phobia. But we have seen it haven't we in these pages not so long back where a '44 dropped half the T/R gearbox off or just the hub and blades assy? I do not remember which and landed, although I think from a very low height perhaps before it could become vertical?

Wasn't that Huey followed by another AC when some testing was being done checking some theories as to why the first one crashed as only our RAAF would do? A departed friend of mine who had a few hours also on the Huey but in a Mirage that day in the circuit watched that one as the M/R again stayed in the same place, the rest descending very quickly. A friend if his driving the Huey. The testing involved fast pushovers I believe.

Reminds me of a story from my dear old dad. Townsville towards end of war the locals got to hear about the compressibility problems they were having in Europe chasing fast things downhill. 86 Squadron Mustangs boss decided they should test and find out what the issues were. Dad who was in the sister squadron said one day they heard an engine hit blue note, looked up in time to see a machine coming out of the sky very fast, they found one boot.

Like you say don't do these things at home.

4thethrill, if you are above the AFM minimum weight and the Cof G is still wrong, please don't fly until you get someone qualified to work it out and fix it.

cheers tet

[Boudreaux Bob]

TET,

Who said anything about flying away with no Tail Rotor Gearbox?

I suppose Huey/Huey Cobra incidents and crashes during the Vietnam War were Military Secrets as apparently many have not heard about some of them.

One example, there there a photo of a Tail Rotor Blade stuck crossways through the Tail Fin of an H Model Huey somewhere.

The Aircraft Commander of that aircraft is still Test Flying Apaches for the US Army down at Fort Hood.

Tail Booms do not always fall off when it happens, Main Rotor heads do not chop off every Tail Boom, and it does not always result in a catastrophic disaster.

There was a Bell 412 that experienced this one night in the GOM. The ride to the water was quite an experience for the Crew but they managed to regain control and ditch with everyone surviving.

Absolutely it could be considered a Phobia but I see it as simply being aware of how a helicopter reacts to various malfunctions.

[Collective Bias]

Sky Shuttle did it in the AW139 not to long ago......


CB

[MightyGem]

You can catch the Lynx simulator after a T/R drive failure in the cruise. You end up in a left bank, nose down attitude. Gives you time to think about where you're going to do the engine off to. Just don't try and change heading.

What it would be like in the real thing is anyone's guess. :eek: