troops helping out in Donegal...

[ropebag]

Range drops off fast when you start slinging loads under a chopper. Normally if you add max fuel and max payload to the empty weight you exceed the MTOW of the aircraft. Max range is always with max fuel but little load...

do you actually know the fuel burn rate/range of an AW-139 with 3/4 crew and lugging bulky underslung loads, or do you - and Dev, that other peddler of the obvious or irrelevent - just enjoy typing out vague platitudes that are so obvious that creatures living at the bottom of the sea roll their eyes when they read them?

yes, like anyone who can upgrade from velcro shoes, i'm fully aware that increasing the weight and drag of an aircraft will increase its fuel burn rate and therefore reduce its range.

so, do either of you actually know whether an AW139 with 3/4 crew could carry a section of Bailey bridge from DFTC to Inishowen without - obviously, given the underslung load - stopping to refuel on the way?

(na grohmiti raises the very sensible point that route selection could be a headache with an underslung load that might plumet several thousand feet at any moment, but i'm interested in whether our heroes actually know the figures they alude to...).

[Truck Driver]

Range drops off fast when you start slinging loads under a chopper. Normally if you add max fuel and max payload to the empty weight you exceed the MTOW of the aircraft. Max range is always with max fuel but little load....

Interesting that. For a no aviation dude like myself, I had to Google MTOW. But then when you think about it, would it not be logical to have two sets of figures for max range (unladen and fully laden)? Just a thought...

[irishrgr]

While slinging a bridge might be a great photo op, just because you can do something doesn't mean you should. As was correctly pointed out, planning a route to avoid any population would be a nightmare. Sling loads are risky enough, consume large amounts of fuel and should only be used when other means are not available. If the bridge can be safely & effectively driven up there, then why fly it? We've had loads of requests from well meaning but otherwise uninformed civilians asking about sling loading everything from pallets of water, boats to trucks for Harvey. Our besieged Air Ops Ctr. politely tells them no, just drive it there in a lorry, we are not slinging anything over the 4th largest city in the US.

As for the LA, if they can't get their act together, their problem. However, in fairness, it takes time to survey damage, decide what's needed and request it.

On a related matter, when the DF do this sort of ATCP, who pays for it? Here if we do ATCP (or Defense Support to Civil Authorities as we call it), the State Govt. has to reimburse the Federal DoD for the cost of fuel, humans, maintenance, etc. Our HQ has all sorts of spreadsheets of costings by the hour/day for whatever. EG: Lakota $1500/hour, HMMV $75/day, Blackhawk $4500/hour, Chinook $7500/hour. troops costing is dependent on rank/grade but by the day. If Army equipment gets broken, then the state has to reimburse the feds the full cost of repairs or replacement.

This is why, as much as governors moan on about "their" National Guard, they are remarkably stingy with deploying them until they get the Presidential Disaster Declaration. Once they get that, then Uncle Sugar with his money shows up and they are happy to start calling up the Guard...

A

[EUFighter]

do you actually know the fuel burn rate/range of an AW-139 with 3/4 crew and lugging bulky underslung loads, or do you - and Dev, that other peddler of the obvious or irrelevent - just enjoy typing out vague platitudes that are so obvious that creatures living at the bottom of the sea roll their eyes when they read them?

yes, like anyone who can upgrade from velcro shoes, i'm fully aware that increasing the weight and drag of an aircraft will increase its fuel burn rate and therefore reduce its range.

so, do either of you actually know whether an AW139 with 3/4 crew could carry a section of Bailey bridge from DFTC to Inishowen without - obviously, given the underslung load - stopping to refuel on the way?

(na grohmiti raises the very sensible point that route selection could be a headache with an underslung load that might plumet several thousand feet at any moment, but i'm interested in whether our heroes actually know the figures they alude to...).

Attachment 8480

The diagram shows the payload range for the AW139 (in Lbs and NM), for an under-slung load you can easily cut the figures in half due to the lower airspeed and additional drag factors. For the crew of 3 we can take a weight of 600Lbs (old money). This leaves then about a ton payload at 80NM which does not reach Donegal and you do not want to be putting the payload down and picking it up again with multiple re-fuelling stops. So a non-stop flight is more in the region of 150NM, which cuts the useful payload down to about 0.5 of a ton. A Bailey bridge weights between 4 and 8 tons per 10ft bay depending on the exact type, so multiple trips would be needed. Also the equipment to prepare the site and deploy the bridge needs also to be moved. That is a lot of weight to move and is the reason why the modern version we use (Mabey Logistic Support Bridge) is packed into standard 20ft or 40ft ISO containers. It is faster to move the whole lot by road using a Scania.

The only time I can think of when a helicopter could help is for very local transport to remote sites from a base closer, such as Donegal Airport.

[EUFighter]

Interesting that. For a no aviation dude like myself, I had to Google MTOW. But then when you think about it, would it not be logical to have two sets of figures for max range (unladen and fully laden)? Just a thought...

First the quick answer!
Normally you can find two range figure which answer you question, the first is normally stated as range with some indication of payload, xxx km with xx passengers. The next is called the Ferry Range, this is the maximum range on the maximum amount of fuel with no payload. Sometime there is an indication that ferry tanks (sometime drop-tanks) have been installed. But as with everything that flies this is only half of the answer.

The long answer is that most published figures on the web are only still air calculation. For the real world the weather can effect range, both in terms of temp and wind. The location of the airports being used, due to their altitudes. The payload configuration due to Centre of Gravity limitations can play a part. For something like a helicopter with a load slung under it the type of load does also affect range, how much drag does it have, how fast can be flown without it becoming unstable etc. Therefore before each mission a lot of planning and calculations has to be done to get the real capability of an aircraft.

[DeV]

do you actually know the fuel burn rate/range of an AW-139 with 3/4 crew and lugging bulky underslung loads, or do you - and Dev, that other peddler of the obvious or irrelevent - just enjoy typing out vague platitudes that are so obvious that creatures living at the bottom of the sea roll their eyes when they read them?

yes, like anyone who can upgrade from velcro shoes, i'm fully aware that increasing the weight and drag of an aircraft will increase its fuel burn rate and therefore reduce its range.

so, do either of you actually know whether an AW139 with 3/4 crew could carry a section of Bailey bridge from DFTC to Inishowen without - obviously, given the underslung load - stopping to refuel on the way?

(na grohmiti raises the very sensible point that route selection could be a headache with an underslung load that might plumet several thousand feet at any moment, but i'm interested in whether our heroes actually know the figures they alude to...).

Have a look at the DFTC FB page picture, we are talking 2 x 20ft containers and 3 x low loaders to move it via road. How much do you think that weighs?

Aw139s have lifted the infantry assault bridge and 105 (approx 1.8 tonnes). It can only carry that kind of a load a very short distance, normally it involves sending a tanker when they are lifting that kind of weight.

How many briefs by AC Aw139 pilots on their capabilities have you been to?

While slinging a bridge might be a great photo op, just because you can do something doesn't mean you should. As was correctly pointed out, planning a route to avoid any population would be a nightmare. Sling loads are risky enough, consume large amounts of fuel and should only be used when other means are not available. If the bridge can be safely & effectively driven up there, then why fly it? We've had loads of requests from well meaning but otherwise uninformed civilians asking about sling loading everything from pallets of water, boats to trucks for Harvey. Our besieged Air Ops Ctr. politely tells them no, just drive it there in a lorry, we are not slinging anything over the 4th largest city in the US.

As for the LA, if they can't get their act together, their problem. However, in fairness, it takes time to survey damage, decide what's needed and request it.

On a related matter, when the DF do this sort of ATCP, who pays for it? Here if we do ATCP (or Defense Support to Civil Authorities as we call it), the State Govt. has to reimburse the Federal DoD for the cost of fuel, humans, maintenance, etc. Our HQ has all sorts of spreadsheets of costings by the hour/day for whatever. EG: Lakota $1500/hour, HMMV $75/day, Blackhawk $4500/hour, Chinook $7500/hour. troops costing is dependent on rank/grade but by the day. If Army equipment gets broken, then the state has to reimburse the feds the full cost of repairs or replacement.

This is why, as much as governors moan on about "their" National Guard, they are remarkably stingy with deploying them until they get the Presidential Disaster Declaration. Once they get that, then Uncle Sugar with his money shows up and they are happy to start calling up the Guard...

A

It Aid to the Civil Authorities (ATCA) not ATCP

AFAIK it is at zero cost to the requestor

[Flamingo]

This is why, as much as governors moan on about "their" National Guard, they are remarkably stingy with deploying them until they get the Presidential Disaster Declaration. Once they get that, then Uncle Sugar with his money shows up and they are happy to start calling up the Guard...

A

I'm sure my Brother - In - Law (ex NY, IN, TX and FL National Guard) (He got around a lot!) once told me that there were different pay scales for troops on State or Federal call-up, the State pay was a lot higher which was one reason States were loath to call out the National Guard until it was absolutely necessary.

Anyway, I digress...

[GoneToTheCanner]

it was ATCP until recently and because it is the State providing a service to the State, in effect, it costs the State nothing, ie, no interdepartmental money transfers. Budgets get thrown out the window for jobs like this and get sorted out later. The local authorities will not be refunding fuel or manpower costs.....heli slinging is mostly very, very short distances, ie, from pad to target being little more than eyeball distance apart.

[irishrgr]

Yeah the rules are weird when a state uses their NG for pure state purposes, every state has different rules. At the end of the day the Guardsmen are on state status, not federal military, so the state decides what to pay them and what benefits to provide. Generally they are not as well paid as when on federal status.

The simplest way to understand this is the feds pay for the NG (buy the planes, tanks, weapons, etc.), train the Soldiers and allow a degree of state control for normal operations. When called up for operations like AFG or IRQ, then you are under federal control. It's a quirk of US constitutional law and honestly it's arcane and confusing but it is what it is. Regular Army blokes heads explode when ya try and explain it to them. That's whey for things like Harvey, there are detailed records kept to see which agency owes what once the dust settles. The states and feds have contingency funds set aside for this sort of thing, but not the scale of Harvey. Hopefully Congress might actually pass a budget this year and include this (falls over laughing!!!).

In many ways, this is so much simpler in Ireland, really just one system.

A

[GoneToTheCanner]

Nice picture in today's Irish Times of the Bailey Bridge in place where the old bridge used to be.