Thursday 11 June 2009

Strategic Bombing,Operation Allied Force


During Operation Allied Force/Noble Anvil,the bombing of the Federal Republic of Yugoslavia (now Serbia and Montenegro) in 1999,American B2 Spirit strategic bombers flew from Whiteman Air Force Base,Missouri in the United States of America.


19 B2 bombers were based at Whiteman.

Of these,10 were being upgraded to Block 30 standard and 9 were available for operations.


Of the 9 operational aircraft,1 was used for training,1 was receiving it's final Block 30 upgrades and 1 was undergoing extensive maintenance,leaving 6 aircraft available for combat.


During the 78 day bombing campaign,these 6 aircraft flew 49 sorties,45 of which reached their targets and released ordnance.

A sortie typically lasted 28-32 hours,required 4 in flight refuellings and delivered 16 guided 2,000 pound bombs.


B2 Spirits flew less than 1% of the sorties in Operation Allied Force yet they dropped 11% of all bombs.



Furthermore,while other aircraft were often unable to drop bombs due to bad weather,the B2s flew above the clouds using radar and inertial/Global Positioning System (G.P.S.) guided bombs regardless of the weather conditions.

On a per sortie basis the B2's bombing performance was far better than most other aircraft used in this conflict.

It has been said that "The B–2 was the star of the air campaign over Kosovo".


The total purchase cost of 21 B2 Spirits was $44,754 Million.


Just 6 of these were used in Operation Allied Force due to the upgrades already mentioned.


However,the difficulty in maintaining the low radar signature of these aircraft is such that they can require 124 hours of maintenance for each hour of flight.

Consequently they have mission capable rates as low as 26% and rarely more than 50%.

This means that typically only 5-10 aircraft are available for use at any one time anyway.



It had then actually cost $7,459 Million to field each of the six Spirits used in Operation Allied Force.

Approximately 700 bombs were dropped by B2s during the 78 day campaign with a hit rate of around 87%.


That is a rate of 1.5 bombs dropped per aircraft per day or 1.3 bomb hits per aircraft per day at a cost of $7,459 Million per aircraft.

That does not include the cost,approximately $800 Million,of the four tankers required to get the strategic bombers to their targets in the first place.


The total capital cost of around $8,300 Million for the B2 bomber and it's supporting tankers is similar to the cost of a British Queen Elizabeth class aircraft carrier and it's airwing.


Yet the aircraft carrier,operating from the Adriatic Sea,could deliver at least 100 times as many bombs on target per day as the bomber and do so without any aerial refuelling support as all targets would be within the unrefuelled tactical radius of it's aircraft.

Whether the carrier is equipped with Super Hornets,Rafales,Typhoons or Lightning IIs (F35 B or F35 C),all targets in the Federal Republic of Yugoslavia would lie within the unrefuelled tactical radius of it's aircraft when carrying 4 2,000 pound bombs.

No target being more than 300 miles from potential operating locations of the carrier.


If each of the 36 aircraft onboard such a carrier flew just one strike mission per day they would between them deliver 144 2,000 pound bombs in a day.

It is possible for a carrier to generate far more sorties than that.

British carrier aircraft were flying as many as 4 sorties per aircraft per day during the Falklands war in 1982.

The American aircraft carrier U.S.S Nimitz has demonstrated the ability to fly 200 strike sorties per day,4 sorties flown per fighter per day for 4 days,her captain thought she could have kept that rate up for a week.

The next generation American carrier U.S.S.Gerald R. Ford is designed to generate up to 5 strike sorties per aircraft per day.


Given the short distances involved,each sortie from a carrier in the Adriatic would take about one hour.

Under combat conditions carriers can turn aircraft around between sorties in under an hour,giving a total cycle time of about two hours per sortie over the Federal Republic of Yugoslavia.

There is then the time for the carrier to generate as many as many as 5 sorties per aircraft in a single day while still leaving plenty of time for rest and maintenance.

Such a sortie rate would deliver 720 2,000 pound bombs in one day.

That is as many bombs delivered in a single day as the entire B2 bomber fleet dropped in 78 days of Operation Allied Force.

Which is rather impressive when one considers that the bombers and their tanker support cost 5 times as much as the carrier and it's air wing.

It is also 480 times as many bombs dropped per day as could be delivered by a single B2 Spirit and it's tankers at the same capital cost as the carrier and it's air wing.

In terms of bombs per day per dollar,even when one allows for the cost of the aircraft carrier's escort support ships and availability of ships and aircraft,the B2 Spirit still appears to offer exceedingly poor value for money.

Wednesday 10 June 2009

Distance To Target,Operation Allied Force



During Operation Allied Force/Noble Anvil,the 1999 bombing of the Federal Republic of Yugoslavia (now Serbia and Montenegro),land based aircraft of the Royal Air Force operated from bases at Solenzara in French Corsica,Royal Air Force base Bruggen in Germany,Ancona in Italy,Aviano in Italy,Gioia Dell Colle in Italy and Practica Di Mare in Italy.



4 Tristar tankers and 5 VC10 tankers flew from Ancona (3 of the VC10s had initially operated from R.A.F.Bruggen).



3 Sentry Airborne Early Warning and Control aircraft flew from Aviano.



8 Tornado ground attack aircraft and 3 VC10 tankers flew from R.A.F. Bruggen (the Tornados later stood down when other Tornados deployed to Solenzara and the VC10s then moved to Ancona).




16 Harrier ground attack aircraft and 1 Canberra photographic reconnaissance aircraft flew from Gioia Dell Colle.




1 Nimrod R1 flew from Practica Di Mare.




12 tornado ground attack aircraft flew from Solenzara.


During the same conflict,aircraft carriers operated in the Adriatic and Ionian Seas.


In addition,American strategic bombers flew sorties from bases in England and the United States.


Other allied support aircraft and fighters and unmanned air vehicles also operated from bases in Albania,Bosnia Herzegovina,England,France,Greece,Hungary,Italy,Netherlands,Poland,Spain and Turkey.



An aircraft carrier sitting 25 miles off the Adriatic coast of Montenegro is 217 miles from Belgrade,130 miles from central Kosovo,25 miles from the nearest border of the Federal Republic of Yugoslavia and 298 miles from it's furthest border.


Gioia Dell Colle is 330 miles from Belgrade,240 miles from central Kosovo,140 miles from the nearest border of the Federal Republic of Yugoslavia and 406 miles from it's furthest border.


Aviano is 390 miles from Belgrade,475 miles from central Kosovo,300 miles from the nearest border of the Federal Republic of Yugoslavia and 551 miles from it's furthest border.


R.A.F. Bruggen is 795 miles from Belgrade,915 miles from central Kosovo,687 miles from the nearest border of the Federal Republic of Yugoslavia and 980 miles from it's furthest border.


Ancona is 360 miles from Belgrade,390 miles from central Kosovo,260 miles from the nearest border of the Federal Republic of Yugoslavia and 485 miles from it's furthest border.


Practica Di Mare is 457 miles from Belgrade,438 miles from central Kosovo,318 miles from the nearest border of the Federal Republic of Yugoslavia and 557 miles from it's furthest border.


Solenzara is 590 miles from Belgrade,590 miles from central Kosovo,464 miles from the nearest border of the Federal Republic of Yugoslavia and 698 miles from it's furthest border.


Aircraft from other nations flew from these and other bases.

Tuesday 9 June 2009

Sortie rates,sortie types and factors in sortie generation

A sortie represents one flight by one aircraft.
A sortie rate is the number of sorties which an aircraft (or a group of aircraft) can fly in a day.
The lower the sortie rate,the greater the number of aircraft that will be needed to generate the required number of sorties in a given time.
The greater the number of aircraft needed,the greater the cost.
Sorties flown by combat aircraft may be split into two types,delivery sorties and persistent sorties.
Delivery sorties may include bombing sorties,transport sorties,reconnaissance sorties and tanker sorties.
The objective of a delivery sortie is to deliver bombs,cargo or fuel or gather intelligence and then return to base.
The shorter the time it takes to fly a delivery sortie and turn the aircraft round for the next sortie,the greater the number of sorties which may be flown in a day by a given number of aircraft.
Flying more delivery sorties per aircraft delivers more bombs,cargo,fuel or gathers more intelligence for a given expenditure on aircraft.
The objective of persistent sorties is to keep an aircraft on station for a given period of time.
Persistent sorties may include,surveillance sorties,fighter patrol sorties and close air support sorties.
Time on station is the the duration of the sortie minus the time taken to transit to and from the operational area.
Longer sortie duration and shorter transit times give more aircraft on station in the operational area for a given number of aircraft and hence for a given cost.
Note that reducing the distance between the operating base and the operational area both increases sortie rates for delivery sorties and increases time on station for persistent sorties.
For the basic mathematics associated with sortie generation see here: www.rand.org/pubs/monograph_reports/MR1028/MR1028.appb.pdf
It will be noted that the sortie rate is determined by both the length of time it takes to fly the sortie,flight time,and the time it takes to prepare the aircraft for the next sortie,ground time.
We shall refer to the combination of these two factors as cycle time.
Ground time can be divided into the time taken to perform routine tasks between sorties,turn around time,and the time taken to perform maintenance to the aircraft,maintenance time.
The flight time is a factor of the speed of the aircraft,the distance to the target and the time on station.
A slow aircraft flying a long distance to the operational area and spending a long time on station will result in a long flight time.
A fast aircraft flying a short distance to the operational area and spending little time on station will result in a short flight time.
The maintenance time depends on the flight time,the aircraft type and the environment in which the maintenance is being done.
An aircraft which flies long sorties,requires many maintenance hours per flight hour and is maintained by unmotivated,tired personnel working in difficult conditions is going to spend a long time undergoing maintenance between sorties.
An aircraft which flies short sorties,requires few maintenance hours per flight hour and is maintained by well motivated,energetic personnel working in ideal conditions is going to spend very little time undergoing maintenance between sorties.
The turnaround time is a factor of the base from which the aircraft is operating and the armament which muct be loaded on the aircraft.
An aircraft at a large crowded,improvised expeditionary airfield (expeditionary airfields are neccessarily two dimensional,dispersed,unsuited to automattion and hence manpower intensive),requiring a large complex weapon load may spend a lot of time taxiing,waiting and being armed.
An aircraft on a purpose built aircraft carrying ship (aircraft carriers are neccessarily compact,three dimensional,well suited to automation and hence can be very manpower efficient),requiring a minimal weapon load may spend very little time taxiing,waiting and being armed.
It follows from the above that aircraft flying from aircraft carriers stationed close to the operational area will generate higher sortie rates than those based at expeditionary airfield further away.
However,if the expeditionary airfield is significantly closer to the operational area than the aircraft carrier then shorter flight times may offset the generally longer turnaround times of the land base.
Whichever basing option which,through it's combination of efficiency and shorter distance to target,offers the higher sortie rate will allow more air power to be delivered by fewer aircraft.

Saturday 6 June 2009

A Comparison Of Sortie Rates For Land Based And Carrier Based Aircraft In Recent Conflicts



During the 30 day invasion of Iraq in 2003 (Operation Telic/Iraqi Freedom),113 land based aircraft of the Royal Air Force flew 2,481 sorties.

A rate of 0.73 sorties per aircraft per day.

During the same conflict the American aircraft carrier U.S.S. Kitty Hawk,with 70 aircraft aboard,flew 3,000 sorties in 28 days.

A rate of 1.53 sorties per aircraft per day.

During the 78 day bombing campaign against Serbia in 1999 (Operation Allied Force/Noble Anvil),41 land based aircraft of the Royal Air Force flew 1,516 sorties.

A rate of 0.47 sorties per aircraft per day.

During the same conflict the American aircraft carrier U.S.S. Theodore Roosevelt,with 71 aircraft aboard,flew 4,270 sorties in 55 days (she then sailed to The Gulf and flew another 2,600 sorties over Iraq).

A rate of 1.09 sorties per aircraft per day.

During the six week long liberation of Kuwait in 1991 (Operation Granby/Desert Storm),158 land based aircraft of the Royal Air Force flew 6,000 sorties.


 A rate of 0.9 sorties per aircraft per day during the 43 day air war.

See here:www.raf.mod.uk/rafcms/mediafiles/F21F8E7A_BD8A_55BA_43FA63F04FC5D6B4.pdf.


 During the same conflict the American aircraft carriers in the Gulf were U.S.S.Midway,U.S.S.Ranger and U.S.S. Theodore Roosevelt.

See here: www.fas.org/man/gao/nsiad98001/a5.htm. U.S.S.Midway,with 56 aircraft aboard,flew 3,019 sorties.


 A rate of 1.25 sorties per aircraft per day over 43 days or 1.59 sorties per aircraft per day over her 34 operational days. 


 U.S.S.Ranger,with 62 aircraft aboard,flew 3,329 sorties.


 A rate of 1.25 sorties per aircraft per day over 43 days or 1.59 sorties per aircraft per day over her 38 operational days. U.S.S.Theodore Roosevelt,with 78 aircraft aboard,flew 4,149 sorties.


 A rate of 1.24 sorties per aircraft per day over 43 days or 1.36 sorties per aircraft per day over her 39 operational days.

During the 192 day MED 05 deployment of the American aircraft carrier U.S.S. Theodore Roosevelt,Carrier Air Wing Eight (C.V.W. 8) flew 16,000 sorties.

A rate of 1.1 sorties per aircraft per day sustained for over six months.