Table Of ContentCOMBAT 126
AIRCRAFT
Edward M Young
B-25 MITCHELL
UNITS OF THE CBI
126
B‑25 MITCHELL UNITS OF THE CBI
SERIES EDITOR TONY HOLMES
126
Edward M Young
B‑25 MITCHELL UNITS
OF THE CBI
C O N T E N T S
INTRODUCTION 6
CHAPTER ONE
BUILDING AN AIR OFFENSIVE IN THE CBI 10
CHAPTER TWO
ALLIED PLANS AND JAPANESE OFFENSIVES 43
CHAPTER THREE
VICTORY IN BURMA, DELAY IN CHINA 70
APPENDICES 91
COLOUR PLATES COMMENTARY 92
INDEX 96
6 IntroductIon
INTRODUCTION
In his classic work On War, Carl von Clausewitz noted the importance During the final months of the war the
1st BG received new B‑25Js, including
of lines of communication connecting an army to its operational
some solid nose strafer versions. Three
base. Over these arteries, as von Clausewitz called them, flowed the J‑models from the 1st BS fly in formation in
materials and supplies necessary to sustain an army at war. Disrupting May 1945. These machines carry their
USAAF serial numbers and their 1st BS
or cutting these arteries could, he argued, cause an army ‘to wither and
aircraft numbers, but no squadron insignia.
die’. As armies modernised and acquired rapid‑firing rifles, machine guns, Application of serial numbers on CACW
artillery, motor vehicles, and the full range of other equipment necessary B‑25s varied considerably (Courtesy Carl
Molesworth)
for modern warfare, the issue of supply and sustaining logistical support
to armies in the field became more complex, and their dependence on
lines of communication more critical. In von Clausewitz’s era, an army
could cut its opponent’s lines of communication through envelopment
or a turning movement. A hundred years later a new weapon of war, the
aeroplane, created an entirely new method of attacking an enemy’s lines
of communication and his sources of supply.
Aerial interdiction, as it came to be called, had its origins in the early
months of World War 1, when French and British aircraft bombed railway
lines that the German armies were using to aid in their advance. From then
until the end of the conflict in November 1918, French, British and, later,
American bombers carried out regular attacks on railway lines and supply
depots in enemy‑held territory.
In the post‑World War 1 era, air power theorists saw an enemy’s supply
system as a primary objective of bombardment aviation. Enemy lines of
IntroductIon 7
communication carrying supplies to the front were considered to be the
most promising targets for bombardment. Railways were the backbone
of land transportation and often had numerous points of vulnerability
such as bridges and tunnels. Rail facilities, like marshalling yards, had the
additional benefit of being large, fixed targets that were relatively easy to
identify and attack.
After World War 1, American air power theorists conceived of
bombardment aviation as having two missions – tactical missions intended
to have an immediate impact on the battlefield, and strategic missions
against targets at a greater distance from the battlefield that would have a
delayed impact on operations of ground forces. Over time the definition
of these operations changed so that tactical missions came to incorporate
aerial interdiction in support of ground forces, while strategic missions
in American air power doctrine shifted to an emphasis on the defeat of
an enemy nation through attacks on its economic system and its ability
to make war.
As a result of combat experience in the early years of World War 2,
and the intense debate over the control of air power, these distinctions
in tactical and strategic missions came to be incorporated in a new
statement of American air power doctrine entitled FM 100‑20
Command and Employment of Air Power, published in July 1943.
FM 100‑20 defined the mission of the tactical air force in a theatre of
war as the attainment of, first, air superiority, second, preventing the
8 IntroductIon
movement of enemy troops
and supplies to or within the
theatre, and third, to carry
out attacks in the immediate
battle area in support of the
ground forces. To prevent
the movement of supplies,
the tactical air force would
conduct attacks on enemy
lines of communications,
supply depots, troop
concentrations and other
military installations
with the objective of
isolating the battlefield to
weaken the opposing enemy
ground forces.
Tactical aerial
interdiction came to be
seen as the primary mission
of what by the late 1930s
and early 1940s were
called medium bombers
to distinguish them
from the heavy bombers
that would make up the
strategic bombing force.
In August 1939 the US
Army Air Corps (USAAC)
announced orders for
184 North American
Aviation B‑25 Mitchell
and 201 Martin B‑26
Marauder twin‑engined
medium bombers to replace its older twin‑engined Douglas B‑18
Bolos. The USAAC (soon to become the US Army Air Force) assigned
these new aircraft to specially designated medium bomber units
known as Bombardment Group (Medium). By the end of the war
North American Aviation had delivered 9816 B‑25 bombers to US
and Allied air forces, with Martin providing 5266 B‑26s. American
medium bombers served in every theatre of war, but of the two types
the Mitchell saw the most widespread service.
In the China‑Burma‑India (CBI) Theatre the B‑25 Mitchell provided
the backbone for the aerial interdiction campaigns conducted over
Burma and China by the USAAF’s Tenth and Fourteenth Air Forces
from June 1942 until August 1945. At their peak in October 1944,
there were no fewer than 304 B‑25s serving with two USAAF medium
bombardment groups (one assigned to the Tenth Air Force and the
other to the Fourteenth Air Force). An additional 60 or so Mitchells
were assigned to the 1st Bombardment Group (Medium) Provisional
IntroductIon 9
of the Chinese‑American Composite Wing (CACW), which was
also serving with the Fourteenth Air Force in China. Finally, 70 to
80 B‑25s equipped reconnaissance and training units and served as
high‑speed transports for senior officers in India and China.
The aerial interdiction campaigns in Burma and China were long,
difficult and relentless. While the B‑25 units in the Tenth and Fourteenth
Air Forces may not have faced the same level of danger from flak and
fighters as their counterparts in Europe or the Pacific, they had to
cope with often appalling weather, geographical constraints, shortages
of aircrew, aeroplanes, spare parts and especially gasoline, and the
A B‑25H from the 82nd BS/12th BG after resourcefulness of Imperial Japanese Army (IJA) engineers who could
dropping bombs on an IJA supply area in seemingly repair railway bridges and marshalling yards as fast as Mitchell
Kinu, Burma, on 12 November 1944. The
crews could bomb them.
objective of interdiction was to disrupt
the flow of materiel to the enemy through Aircrew flying missions into Burma knew that if they were shot
attacks on its lines of communication and down, they had little chance of escape, and a far greater likelihood
supply depots (3A‑37580, Record Group
of ending up in a brutal Japanese prison camp. As the CBI had a far
342H, National Archives and Records
Administration (NARA)) lower priority than the European or Pacific theatres until well into the
war, there were rarely enough
aeroplanes to carry out the
sustained and concentrated
attacks required for a
successful aerial interdiction
campaign, which was above
all a battle of attrition. A
further hindrance was the
fact that the IJA, unlike its
American, British or German
counterparts, relied on a
much lower level of supplies
for its daily existence. Aerial
interdiction is more successful
when the enemy force has a
high rate of consumption.
Successful aerial interdiction
campaigns also require
sustained pressure on the right
targets – a function of good
intelligence on an enemy’s
logistical system and careful
target selection. In a country
as vast as China, this was not
always possible. Nevertheless,
the B‑25 medium bomber
groups in the CBI kept up
their efforts despite these
constraints, and over time
crews developed the tactics
and techniques that made the
Mitchell an effective aerial
interdiction weapon.
10 CHAPTER ONE BuIldIng An AIr offEnsIvE In thE cBI
chAPtEr onE
BUILDING AN AIR OFFENSIVE
IN THE CBI
In 1942 the War Department created the China‑Burma‑India Theatre, In Burma the monsoon season lasts from
the beginning of May to the end of
under the command of Lt Gen Joseph Stilwell, to oversee all American
September, covering much of the country in
operations in support of China. The theatre’s area of command stretched cloud and heavy rain. The weather in
from Karachi (then part of India) to eastern China, a distance of more than central Burma is somewhat better, and this
allowed the B‑25s to continue missions but
3300 miles by air, encompassing all of India, China and Southeast Asia.
at a reduced rate. These two 490th BS
America’s objective was to ensure that Chinese forces continued to resist bombers were photographed flying through
Japan, thereby containing the nearly one million Japanese soldiers and broken clouds. The closer aircraft has the
revised national insignia, incorporating a bar
airmen stationed in China and Manchuria. American military planners
with a red surround, authorised in June
also saw China as a likely base from where USAAF heavy bombers could 1943 (3A‑33618, RG342H, NARA)
launch a strategic aerial campaign against Japan. Finally, China was being
considered as a possible base from where to launch an invasion of Japan.
The loss of Burma in early 1942 cut China’s last line of land communication
to the west, leaving only the precarious air route from northeast India over
the Himalayas to China that became known as the ‘Hump’. In February
1942 the USAAF activated the Tenth Air Force to control all air operations
in the CBI. It was led by Maj Gen Lewis Brereton, former commander of the
Far East Air Force in the Philippines and Deputy Commander, Air Forces,
American‑British‑Dutch‑Australian Command. Brereton brought with him
