Cat 5.  ML-KNIL

Orginal texts by Wilko Jonker / Translated by Ronald van Voorst  (lees Nederlandse versie hier…)


Purchase by the Dutch Purchasing Committee

Due to the threat of war, this Dutch committee, operating from New York, intensified its activities begin 1940 to obtain various airplanes and to expedite its ordering and delivery. The Netherlands were attacked in May 1940 and were occupied. The Committee however continued its activities, now for the modernisation and strengthening of the forces in the Dutch Indies. In Europe The Netherlands had to surrender to Germany May 1945. But the vast Colony of the Dutch East Indies were still under full Dutch control.

For Dutch Indies defense, in June 1941, 162 medium bombers were purchased, intended to replace the obsolete Glenn Martin type 139 and type 166 planes. The Militaire Luchtvaart (ML) contract for the “emergency” delivery of 162 NA-90 B-25C-5’s was signed on 30 June 1941 (so still before the Japanese started the war with the attack on Pearl Harbour in December 1941). The production and delivery were scheduled after the finalisation of the current USAAF contract. At the insistence of the ML an accelerated delivery schedule was agreed with the Americans in mid-August 1941. Due to the precarious situation in the Dutch Indies, the USAAF agreed to relinquish planes from their own contract to the ML. These would then later be replenished from the ML contract. The delivery flights used two routes: to India via Africa and over the Pacific via Hawaii to Brisbane.


Detachment Bangalore (British Indies)

As it was reported that 20 B-25C’s were en-route to India via the Africa-route, eight crews left Java in March 1942 to go to Bangalore in India. The group was led by Wittert van Hoogland and consisted of six pilots, seven engineers and six radio operators. The first of the eight Mitchells that were sent arrived on March 8 and on March 9, five airplanes were present. The sixth plane had crashed in Africa and the remaining two were damaged at Palm Beach.

The B-25’s were marked with a letter following the RAF regulations. They were equipped with Norden bomb sights that were at that time still very confidential. (Airplanes that were delivered later were equipped with the inferior Sperry bomb sight.)

On 8 March 1942, the Dutch Indies capitulated and occupied by Japan. This meant that deliveries to Java were meaningless and that B-25’s therefore never arrived there.

Various Mitchells were present in Australia and in British Indies and deliveries continued as it was the intention to operate these planes in the war effort from free Allied territory.

After a demonstration flight on 24 March 24 for the British Air Marshal Sir Peirse (commander RAF British Indies), the idea was put forward to employ the B-25’s for "photo reconnaissance". As this concerned a new concept airplane, problems arose regarding equipment and parts, but fortunately, a lot of useful material could be taken over from the KLM and many practice flights were made. Early April confirmation was received from London to form a PRU (Photo Reconnaissance Unit) for the RAF in British Indies. Between 18 April and 10 May, the B-25’s moved to Karachi where the modifications for the camera work were completed. The Dutch military personnel did not like the idea and arranged that they left British Indies on 3 July by boat for Fremantle near Perth in Australia. Their five B-25’s that had arrived were transferred to the RAF and were assigned to No. 684 Photo Reconnaissance Squadron. (At the same time also three Lockheed 212’s that had escaped the Dutch Indies were transferred).


Detachment in Australia

A detachment present in Australia (group Boot), consisted of 18 pilots, 7 radio operators and 14 mechanics led by Captain Boot.

On 2 March 1942, the first of 18 B-25C’s arrived on Archerfield near Brisbane. This was the start of the first delivery of 60 planes. It was agreed to set up an Netherlands East Indies (NEI) wing in Australia by the Dutch and Allied Commanders and allocated within the RAAF. The first twelve B-25’s in Australia carried Netherlands Indies (NEI) numbers and orange triangle markings. According to available photographs, the registrations were N5-120 through N5-131. The B-25’s that were supposed to come via India would get the numbers N5-139 through N5-148. The next delivery of 24 planes arrived in March and April 1942. These were however handed over to the USAAF that urgently needed aircraft in accordance with an agreement that of the 54 B-25’s that were to be delivered, 18 would go to the NEI and 36 (and the 6 already delivered) would go to US units.

On 1 April 1942 five Dutch B-25C’s were present in Australia. These were N5-132, N5-134, N5-136, N5-151 and N5-161. These only had one 0.303 inch machine gun in the nose and two 0.303 inch machine guns in the turrets and were vulnerable for attack from head-on. The markings consisted initially of orange triangles, but these were soon painted out with the Dutch flag. It took quite some effort to keep these five B-25’s for the ML. By June, only these five were present as the remaining 13 were not delivered yet.

April 4, 1942 officially the first Netherlands East Indies (NEI) squadron was established and agreed by the Allied commanders, the No.18 NEI squadron at RAAF Fairbairn, the former Station Canberra aerodrome. The squadron had a mix of a Dutch and Australian military personel and was part of the RAAF no.79 Wing. Soon about 240 Dutch and 200 Australian men were assigned. The squadron had large difficulties to get started, set up facilities, get spare parts and to get additional aircraft. Morale was low and the intended squadron / wing commander Boot was not popular so assigned an liaison position and NEI no.18 command was taken by major Fiedeldij.

On June 4, an urgent request was received to co-operate in tracking down a Japanese submarine. On June 5, two B-25’s of No.18 Squadron flew sorties. B-25 "N5-151" bombed a Japanese submarine which was sunk off the coast near Sydney.

During July 1942 the available planes were re-numbered. This was likely done as the overview was lost due to the different partial deliveries. Between 20 August and 21 September the third partial delivery too place. As agreed, six planes were returned to the Americans.

The new aircraft differed from the first six delivered. They now had 0.50 inch machine guns instead of the 0.303 inch ones and had improved turrets. The (new) B-25C’s were equipped to carry external fuel tanks under the wings (the B-25D’s could not do this). A big disappointment was the primitive inaccurate Estoppey D-8 bomb sight that was installed, compared to the modern Norden D-7 equipment present in the first six planes. The range of the B-25C/D was 400 miles without the external fuel tanks. With the external tanks the range increased with 600 miles. In the autumn of 1942, N5-131 was tested with a small 300 gallon fuel tank in the bomb bay. The bomb load was in that case 6 x 100 lbs or 3 x 500 lbs. The test was a success, so in November / December 1942, the 300 gallon tank was installed in all planes. Until the end of 1942, additional B-25C-10’s and B-25C-15’s were received.

The Canberra field was in fact to far from the War theatre and its runway very awkward. In December 1942 the squadron personnel and equipment was moved finally to McDonald Airfield west of Stuart Highway near Pine Creek in the Northern Territories. The aircraft followed soon and they started to conduct raids against mostly Japanese shipping. In practice, the Bendix gun turrets caused many problems, so these were therefore removed in most cases.

The concept of “skip-bombing” entailed approaching the target at very low altitude and then drop the bombs. These then bounced against the target. The disadvantage of this method was the heavy defense of the target, against which the B-25 had few counter measures. Therefore a heavier forward armament was needed. As the bombardier was not needed for attacks at low altitude (mostly ships), the space could be used for a packet of four fixed 0.50 inch machine guns. These protruded from a metal plate that replaced the flat glass panel of the bombardier. Also four additional 0.50 inch machine guns were installed in external blisters on both sides of the fuselage. A metal plate protected the fuselage against the muzzle blast.

Following a reconnaissance flight with B-25C N5-133 on 30 March 1943, during which a fight took place with three Zeke’s and from which the plane returned with its fuel tanks almost empty, Commander Fiedeldij wrote a letter regarding the deficient armament and the too long distances for the operations. Referring to an American report, he suggested to improve the frontal armament (for attacks at very low altitude), to replace the ventral gun turret with a 300 gallon fuel tank, to add a flexible machine gun in the tail and to modify the bomb aiming mechanism such that it could also be operated by the pilots (now this could only be done by the observer/bombardier located in the nose).

May 1943 the No.18 squadron moved to Batchelor field near Darwin in the Northern territories. The facilities were there much better. In May 1943, permission was given to install heavier armament in five planes. N5-129, N5-137, N5-141, N5-143 and N5-145 were equipped with four 0.50 inch machine guns in the nose and two times two 0.50 inch machine guns in single pack blisters on the fuselage sides below the cockpit. The ventral gun turret was removed from these planes. The other planes only received the additional machine guns in the fuselage blisters. The modification of the bomb aiming mechanism for operation from the cockpit was not installed. After some adjustments, more planes were modified. Probably also additional fuel tanks were installed, improving the combat range significantly. Japanese ships were attacked at extreme low level as well as other targets.

At the end of February 1943, 12 strafers were delivered to 90th Squadron at Eagle Farms, Australia. The strafer concept was so successful, that by mid-September 1943, 175 B-25C’s and D’s were converted by the depot in Townsville, Australia, including the five Dutch planes

In May 1943 the first B-25J-1 was delivered. The J-version had two 0.50 inch machine guns in the nose, two 0.5 inch machine guns in the tail, and two 0.50 inch machine guns in the dorsal turret. This turret was moved to the front. A twin-pack of two 0.50 inch machine guns was added to each side of the fuselage. An extensive registration and type listing can be found in the books of O.G.Ward and Mr. Tornij.

Mid-July 1943, the obsolete Estoppey D-8 bomb aiming equipment was replaced by the more modern Sperry equipment.

From September 1943, eight B-25D-20’s were transferred by new pilot from the RNMFS. These planes are designated by O.G.Ward as D-modified.

Based on photographs, these planes had machine gun positions in the side of the fuselage and in the tail. The side positions strongly resembled those of the later B-25H and -J. Due to the placing of the dorsal turret however, the side positions were directly opposite to each other. In the –H and –J versions the dorsal turret was moved to just behind the cockpit which left more space in the fuselage to stagger the side machine gun positions. Also the tail machine gun position was similar to that in the –H and –J, but it was less pronounced and was equipped with only one machine gun.

Between January and April 1944, another 50 B-25D’s arrived. On page 21 of the book  (?) “Squadrons van de Koninklijke Luchtmacht” a row of B-25D’s can be seen. These were the last B-25’s that were transferred by pilots of the RNMFS in Jackson (like N5-193, with a gremlin emblem in an orange triangle). These planes, that were equipped with single gun packs on the fuselage, were not all needed anymore and the surplus of about 20 was transferred to the RAAF: in this way, N5-183 became A-47-1, N5-187 became A-47-2 etcetera.

The No.18 squadron continued to fly from Batchelor until April 1945 and than moved to the Dutch Indies Balikpapan at Borneo to continue attacking the Japanese until VJ-Day. Also a start was made with making the "Leaflet flights" (see below). The No. 18 squadron was very succesful and soon had the nickname "Dutch Cleanser".


Transport B-25 planes

PEP: On September 1, 1943, the NEI Aircraft and Personnel Pool (NEI-APP), Personnel and Equipment Pool (PEP) was established, to cover the personnel and material supply for the 18th and 120th squadrons. This unit acted as the reserve for material (like P-40’s and B-25’s) and for personnel.

NEITS: The supply of the 18th and 19th squadrons was provided by the NEITS. In January 1944, the NEI Transport Section Melbourne was activated, equipped with Lodestars and stripped B-25’s. The B-25’s N5-128, N5-129, N5-134, N5-142 and N5-143 were already used by the 18th squadron as TB-25’s and were transferred mid-September 1943 to No.2 NEITS. The section Melbourne was given squadron status by mid-September 1944: No.1 NEI Transport Squadron. The section Brisbane became No. 2 NEI Transport Squadron equipped with 3 Lodestars and 5 TB-25’s. On November 7, 1944, the two units were combined and became no. 1 NEITS. The 20th Squadron was created in Tjililitan on 1 November 1946. The squadron was at that time equipped with 11 TB-25’s. The following planes were used: N5-138, N5-146, N5-149, N5-152 (?), N5-160, N5-164, N5-173, N5-223, N5-237, N5-239, N5-240, N5-248, N5-250 and N5-261. By May 1948, the remaining TB-25’s were replaced by C-47’s.

During the war, the 18th Squadron had already started with photo reconnaissance activities. A “camera-bay” was installed in a B-25, consisting of a gimbal mounted camera above a hatch in the fuselage. A drift indicator with an interval meter enabled making photographic cycles.

Also two folding side windows were installed to enable “overboard” photographs. Also pictures could be taken from the blisters. (A nice picture of this can be found on page 141 in the book  “Van Glenn Martins en Mustangs of Hugo Hooftman and on page 18, 40 and 43 in the book of Gerben Tornij.) Lots of experience was gained from these first activities, which enabled the establishment of the “Fotodienst” (photographic) office in Batavia in November 1945.


Leaflet flights

In order to help the POWs and other interned civilians in the various prison camps, the so called "Pamfletten vluchten" / Leaflet Flights were made. Leaflets, small supplies and medicines were dropped at the camps. The N5-180 “ADA” and N5-185 “Lienke” were made available for leaflet flights from August 4, 1944. The N5-185 became only available on 24 August 1944, due to repairs on the nose section. The gun turrets and the side armament was removed. Only the machine guns in the nose and tail were retained. Aluminum sheet was used to close the openings. A wooden frame was installed in the tail to hold a 184 gallon fuel tank. Also 23 4-gallon fuel cans were carried. Two fuel tanks were installed in the bomb bay. The planes were thoroughly cleaned from all tar, oil and dust and all paint was removed, followed by polishing. Large Dutch flags were painted below the wings and on the sides of the fuselage to ensure proper identification. Before the first flight, the destination and route were painted on the nose. This first flight took place on 23 September 1944 (N5-180 (42-3454) to Batavia), followed on 24 September by a flight of N5-185 to Bandoeng. N5-180 was no longer used after the first flight. N5-185 flew leaflet missions to Soerabaja, Madioen and Tjilililatan in January 1945.


After VJ-Day

The end of the Second World War after the surrender of Japan took place on Victory Day 15 August 1945.

The Mitchells had been bought by The Netherlands and were therefore given various tasks after the war in order to rebuild the military aviation in The Indies. On 15 August 1945, No.1 NEITS was absorbed into the newly established 19th Squadron. The complement of 19th Squadron initially comprised TB-25D’s N5-188, N5-205 and N5-209 and a number of C-47’s. Mid-October 1945 seventeen C-47’s arrived, of which ten became operational. The old TB-25’s were likely decommissioned at that time. When 19th Squadron was disbanded on April 1, 1948, all material was transferred to 20th Squadron.

The RAPWI (= Recovery of Allied Prisoners of War and Internees) was established on order of Mountbatten. The goal was to take care of the allied prisoners of war and civil internees that had been liberated from the camps. The RAPWI air group employed various aircraft types: two Japanese DC-3’s, about 10 twin engined transport planes, about 15 single engined Japanese training planes and biplanes and also three TB-25’s (including N5-129). The advantage of using Japanese aircraft was that the sometimes abundant Japanese fuel reserves could be used up.

No. 18 squadron was formerly transferred to full Dutch Command January 1946, now obviously with only Dutch personnel.

On February 1, 1946 the VTG was established (Vliegtuig Transport Group). In this unit, 19th Squadron, the transport aircraft of 18th Squadron and parts of the MLD were combined. The VTG was in fact the operational part of the NIGAT (Netherlands Indies Government Air Transport). From 15 August 1946 “civil” call-signs were marked in 12 inch high letters, white on a dark background and black on a bare metal (light) background. For example: N5-129 à VH-RDS. (See page 185 of the book “Camouflage en Kentekens”.)

Actions after VJ-Day in The Indies

Orginal texts by Wilko Jonker / Translated by Ronald van Voorst

The Dutch  No.16 Squadron was established in November 1946 in The Indies equipped with 9 B-25J’s. Until August 1948 the operational base was Palembang. After that date, the unit was combined with the already flying No. 18 Squadron.

Soon after the end of the war, the Dutch B-25’s resumed the fighting – this time against the Indonesian rebels who fought for independence from The Netherlands. The 18th Squadron conducted operations with B-25’s both with observation and strafer noses. Around that time the armament in the gun turrets was removed due to lack of spare parts and money. From 1 April 1949, the B-25’s could only be operated for 15 hours per month !

During the first "Politionele Actie" (Police Action) (21 July 1947) the B-25’s of 18th Squadron were used for reconnaissance flights and to bomb railway lines and artillery positions of the Indonesian Nationalistic TNI.

After this first Politionele Actie the normal activities, mainly providing air support for the ground forces was resumed. In August 1948 16th Squadron located at Palembang was disbanded. The available personnel was assigned to 18th Squadron and stayed at Palembang.

During the second Politionele Actie (19 December 1948), the B-25’s of 18th Squadron were operating from Tjililitan, Semarang, Medan and Andir (Bandoeng). Their task was the support of the ground forces and the elimination of the AURI.

The 18th Squadron was active not only on Java, but also on Sumatra. Two radio stations at Tjoeroep and Kepahiang (South Sumatra) were eliminated and support was given to air landing operations at Djambi (Mid Sumatra). Also many reconnaissance flights were made. In total 18th Squadron flew more than 330 sorties during the 2nd Politionele Actie.

Various other units also used the B-25. A conversion school on Biak near New Guinea used twelve B-25’s from mid-1946 until August 1948 to train both former prisoners of war and new pilots from The Netherlands.

After a reorganisation of the ML, a Photo Section was established in Andir, however without planes and photographic equipment. Only later in 1946, two B-25’s could be collected in Australia. Those aircraft were there converted to FB-25 reconnaissance planes. The FB-25’s were equipped with vertical Fairchild K17 cameras with four different lenses and Fairchild K-20 handheld cameras. The PVA (Photo Verkenning Afdeling) was official established on January 1, 1947. Its principal clients were the topographic services and the ML. By the end of 1947, the PVA was equipped with five FB-25’s, two Mustangs and five Piper Cubs. The FB-25 performed well up to medium altitude,  at higher altitudes it was difficult to take good pictures. The end for the PVA came on 1 March 1950.

The Republic Indonesia was officially proclaimed on 27 December 1949 and the 18th Squadron was dissolved by mid-June 1950. Between 1945 and 1950, twenty airplanes were written off. The 41 remaining planes were transferred to the AURI (Angkatan Udara Republik Indonesia) in June 1950.

Mitchell types used by the ML-KNIL

(please refer to registration data tables)

The B-25C-1 was equipped with a bomb rack under the wings and they could also carry a torpedo when needed.

On the B-25C-5, the 0.303 inch machine gun in the nose was replaced by a movable 0.50 inch machine gun and a fixed 0.50 inch machine gun on the starboard side.

In addition, the single long exhaust pipe was replaced by a number of shorter pipes just below the cooling gills.

The B-25C-10 saw a number of changes in the internal equipment.

The B-25C-15 was equipped with improved Clayton S-shaped flame dampening exhaust pipes for each individual cylinder. These were also installed on all following types. Also an emergency system for the hydraulic landing gear was installed.

Only one B-25D-10 was used (NL-169) with a number of changes mainly to the internal equipment. On the B-25D-15, starting from serial number 41-30353, the Clayton exhaust pipes were installed.

The B-25D-20 from fiscal year number 41-30533 saw modifications like a clear vision wind shield, the installation of a 230 gallon self-sealing fuel tank in the bomb bay (every second plane) and armour plating behind the co-pilot.

The B-25D-25 was from fiscal-year-number 42-87138 equipped with a portable oxygen supply.

The B-25D-30 saw the introduction of the further low temperature modifications, including defrosting for the wind screen.

Finally B-25D-35’s were used.

Many B-25D aircraft later went to the RAAF.

From B-25J-1 with serial 43-4019, the possibility to carry a 2000 pound bomb was omitted. This equipment did not perform satisfactory and was not often used.

Besides a number of internal modifications, the B-25J-5 introduced de-icing panels for the wind screen and gun blast arrestors for the dorsal turret and the side armament.

The B-25J-10 introduced bomb racks under the wings and the necessary operational equipment. The electrically operated bomb racks and the heating for the side armament had proven to be inefficient and was omitted.

The flexible side and front armament of the B-25J-15 was equipped with new direction finders.

A second fixed 0.50 inch machine guns was installed in the nose of the B-25J-20. The flexible nose gun was therefore moved up by 4 inches. Armour was installed in the floor below the bombardier. The canopy of the dorsal turret was strengthened and a hydraulic emergency brake system was installed.

On the B-25J-25 the seats of both pilots were armoured. From serial number 44-30111, armoured deflectors were installed on the fuselage back to prevent hitting the tail planes and the tail turret from the dorsal gun turret.

Stainless steel exhaust pipes replaced the steel ones on cylinders 1, 7 and 9 on the B-25J-30. From serial number 44-31311 an electrical bomb hoist was installed in the bomb bay. From serial number 44-31338 rockets could be carried under the wings (T-64 rocket launchers for eight 5 inch HVAR (High Velocity Aircraft Rockets)). Serial number 44-86692 saw the introduction of equipment to carry glide bombs under the fuselage.

From production block 35 it was possible to carry mines.

The transparent nose could be replaced in the factory with a solid one with eight 0.50 inch machine guns. With this modification, the factory designations were B-25J-11, -17, -22, -27, -32 or -37 depending on the current production block. After the war, the ML carried out this modification by itself (designated as B-25K).


For registration and Photo selection... see Dutch language B-25 page here....


(C) Text and Contents: strictly copyright IPMS NEDERLAND; Researched by Wilko Jonker. No part may be re-used without written permission. 

The content in Dutch was first published Summer 2004 by M. de Vreeze; translated by Ronald van Voorst September 2017