2009/07/22

Airspace deconfliction

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I recall an interesting recount about an early night air raid against Germany (by the UK and maybe Canada). The anti-air artillery (AAA) that protected German cities were exacting their toll, and the British understood that the duration of an air raid over the target was a major variable for the AAA's effect. A longer bomber presence allowed to guns to fire longer = more, and with equal hit chance, therefore achieving more hits.

The RAF Bomber Command decided to reduce that duration to about 20 minutes, but at the same time the air raids were approaching 1,000 bomber strength. The air crews were skeptical and feared many collisions because of this.
The RAF's answer was based on the new discipline of operational research: They told their crews that - according to math - there would be on average just one collision, but more than a dozen bombers would be saved from AAA.
The new tactic was tested one night and it played out exactly as expected (one collision) . It was (with modifications) used many times afterward.


It's remarkable that some (even lethal) accidents were accepted to achieve another, more important and/or more likely advantage.

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Let's contrast this with modern army and air force deconfliction requirements:
These requirements shall ensure that no manned object in the air collides with another object.
Three methods are dominant (and known to me):

(1) restricting assets in altitude (like "aircraft need to fly higher than x,000 ft" or "mortars must not fire higher than y,000 ft")


(2) restricting assets in time (like aircraft being limited to a time window of artillery silence)

(3) asking for permission and coordinating flexibly (but slowly)

Today's battlefields don't have a thousand manned bomber-sized objects over an area like 10 x 10 km. Collisions are much less likely - nevertheless, deconfliction is much more rigorous.

The only viable justification for this could be low opportunity costs; the advantages that are lost due to the deconfliction requirements may be even less important and/or less likely than the tiny collision chances.

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So what are those costs? Here are some examples:

* Mortars are restricted in their firing arcs and less effective especially against high and far targets.

* Artillery is very restricted in its fire support role.

* Helicopter operations are impeded (helicopter need to go low to do their job)

* Use of radio bandwidth.

* Busy signalers and controllers (even the use of E-3 AWACS for airspace control)

* Company and battalion leaders don't use available small UAVs as much as otherwise desirable because airspace deconfliction is too limiting.


Probably most important:
* Support fires are delayed down (impacting after five to ten instead of two to three minutes, for example). This puts troops in combat at risk, makes fire missions obsolete and fire missions against moving or only briefly observed targets impossible

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Does the tiny (like one in a million) chance of a collision justify strict deconfliction requirements at such opportunity costs?

Maybe. Maybe in present conflicts due to the low lethality enemies.
Maybe not.

It's certainly advisable to treat airspace deconfliction as a temporary requirement, though. Its rationality needs to be re-assessed for every new conflict (at the beginning and during the conflict till its end). It must not become gospel, or else we could someday do the equivalent of what the British pilots were about to do; avoid accidents and die in the process due to another problem.

Sven Ortmann

P.S.: This was - like many other points raised by me - in part about how small war experiences and optimization may be a terribly preparation for major warfare in the future.
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3 comments:

  1. Aircraft cost dominate all doctrine, tactics and any other concern you might have. One helicopter runs about $40M to replace. An updated F-16 runs about $80M. An F-22 runs about $330,000M a year so they won't even allow them in combat.

    I don't subscribe to the idea that Afghanistan was the reason the Soviets collapsed (they were already broke) but what can't be denied is that the cost of aircraft replacement was over $2B a year, about double what it took to keep the entire 40th Red army (120,000 soldiers) in Afghanistan. The Red army was using all available aircraft production and couldn't make up loses.

    If the US lost 30 Jets over a year's time in Afghanistan we would be in exactly the same mess.

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  2. I'm quite sure that you got the "$330,000M" wrong.

    The F-22's are rumoured to get few flying hours, let's say a bit less than NATO standard (165hrs) - 150 hrs. Just as a rough estimate.
    The cost per flying hours could be as high as $50,000, more or less. Well, something between $20,000 and 100,000.
    That would put annual variable costs per aircraft at $3M to $15M.
    I don't recall the (already disclosed) figures, but it's certainly one or two orders of magnitude below your value.

    I'm sure the typical suspects - Wheeler and Pike, know the disclosed cost per flying hour.

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  3. I'm speaking of the replacement cost of a destroyed aircraft.

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