Northrop BT: American Dive Bomber

The Northrop BT was an American two-seat, single-engine monoplane dive bomber built by the Northrop Corporation for the United States Navy. At the time, Northrop was a subsidiary of the Douglas Aircraft Company. While unsuccessful in its own right, the BT was subsequently redesigned into the Douglas SBD Dauntless, which would form the backbone of the Navy's dive bomber force.

Design and Development

The design of the initial version began in 1935. It was powered by a 700 hp (520 kW; 710 PS) Pratt and Whitney XR-1535-66 double row air-cooled radial engine and had hydraulically actuated perforated split flaps (dive brakes), and main landing gear that retracted backwards into fairing "trousers" beneath the wings. The perforated flaps were invented to eliminate tail buffeting during diving maneuvers.

The next iteration of the BT, the XBT-1, was equipped with a 750 hp (560 kW; 760 PS) R-1535. This aircraft was followed in 1936 by the BT-1, powered by an 825 hp (615 kW; 836 PS) R-1535-94 engine. One BT-1 was modified with a fixed tricycle landing gear and was the first such aircraft to land on an aircraft carrier.

The final variant, the XBT-2, was a BT-1 modified to incorporate landing gear which folded laterally into recessed wheel wells, leading edge slots, a redesigned canopy, and was powered by an 800 hp (600 kW; 810 PS) Wright XR-1820-32 radial. The XBT-2 first flew on 25 April 1938, and after successful testing the Navy placed an order for 144 aircraft. In 1939 the aircraft designation was changed to the Douglas SBD-1 with the last 87 on order completed as SBD-2s. By this point, Northrop had become the El Segundo division of Douglas aircraft, hence the change.

Operational History

The U.S. Navy placed an order for 54 BT-1s in 1936 with the aircraft entering service during 1938. BT-1s served on USS Yorktown and Enterprise. The type was not a success in service due to poor handling characteristics, especially at low speeds, "a fatal flaw in a carrier based aircraft." It was also prone to unexpected rolls and a number of aircraft were lost in crashes.

Variants

XBT-1: Prototype, one built.

BT-1: Production variant, 54 built.

Type: Dive bomber

National origin: United States

Manufacturer: Northrop Corporation

Primary user: United States Navy

Number built: 55

First flight: 19 August 1935

Developed into: Douglas SBD Dauntless

Crew: two (pilot and gunner)

Length: 31 ft 8 in (9.65 m)

Wingspan: 41 ft 6 in (12.65 m)

Height: 9 ft 11 in (3.02 m)

Wing area: 319 sq ft (29.6 m2)

Empty weight: 4,606 lb (2,094 kg)

Maximum takeoff weight: 7,197 lb (3,271 kg)

Powerplant: 1 × Pratt & Whitney R-1535-94 Twin Wasp Jr. double row radial air-cooled engine, 825 hp (615 kW)

Maximum speed: 193 kn (222 mph, 357 km/h) at 9,500 ft (2,900 m)

Cruise speed: 167 kn (192 mph, 309 km/h)

Range: 1,000 nmi (1,150 mi, 1,852 km)

Service ceiling: 25,300 ft (7,710 m)

Rate of climb: 1,270 ft/min (6.5 m/s)

Armament:

Guns:

1 × forward firing 0.50 in (12.7 mm) Browning machine gun

1 × 0.30 in (7.62 mm) machine gun in rear cockpit

Bombs: 1,000 lb (454 kg) bomb under fuselage

BT-1S: A BT-1 (c/n346, BuNo 0643) was fitted with a fixed tri-cycle undercarriage. This aircraft was damaged in a crash on 6 February 1939, returned to Douglas and repaired to BT-1 standard.

XBT-2: One BT-1 modified with fully retractable landing gear and other modifications.

BT-2: Production variant of the XBT-2, 144 on order completed as SBD-1 and SBD-2.

Douglas DB-19: One BT-1 (c/n346, BuNo 0643), the former BT-1S, was modified as the DB-19 which was tested by the Imperial Japanese Navy as the Douglas DXD1 (long designation - Douglas Navy Experimental Type D Attack Aircraft)

Operators

United States

United States Navy

Notable Mentions in Media

Northrop BT-1s appeared in pre-war yellow wing paint schemes in the Technicolor film Dive Bomber (1941) starring Errol Flynn.

Bibliography

Bowers, Peter M. United States Navy Aircraft since 1911. Annapolis, MD: Naval Institute Press, 1990.

Brazelton, David. The Douglas SBD Dauntless, Aircraft in Profile 196. Leatherhead, Surrey, UK: Profile Publications Ltd., 1967.

Drendel, Lou. U.S. Navy Carrier Bombers of World War II. Carrollton, TX: Squadron/Signal Publications, Inc., 1987.

Gunston, Bill. The Illustrated History of McDonnell Douglas Aircraft: From Cloudster to Boeing. London: Osprey Publishing, 1999.

Kinzey, Bert. SBD Dauntless in Detail & Scale, D&S Vol.48. Carrollton, TX: Squadron/Signal Publications, Inc., 1996.

Listemann, Phil. Northrop BT-1 (Allied Wings No.3). France: www.raf-in-combat.com, 2008.

Swanborough, Gordon and Peter M. Bowers. United States Navy Aircraft since 1911. London: Putnam, Second edition, 1976.


Northrop BT-1, aircraft number 18 of Bombing Five off USS Yorktown pictured in flight on 9 April 1938.

Northrop BT-1, aircraft number 2 of Bombing Five off USS Yorktown, Oakland, March 1940.

Northrop BT-1 of Bombing Five off the USS Yorktown.

Northrop BT-1 of dive bomber squadron VB-5, assigned to the U.S. aircraft carrier USS Yorktown (CV-5). Deliveries to VB-5 began in April 1938.

Aircraft number 10 of Bombing Squadron Five (VB-5) assigned to the Yorktown Air Group in the aircraft carrier USS Yorktown (CV-5). Struck off charge October 31, 1944.

U.S. Navy Northrop BT-1 (BuNo 0815) of dive bombing squadron VB-6, circa 1939/40.

U.S. Navy Northrop BT-1 pictured sitting on flight line outside of a hangar at El Segundo, California.

Eleven U.S. Navy Northrop BT-1s of Bombing Squadron Five (VB-5) pictured sitting lined up. In the background are three Vought SBUs and a USAAC North American O-47. Note the sign at the right: "Notice! Photographing Military Airplanes is Forbidden by U.S. Government!"

Northrop BT-1 modified to test tricycle landing gear, circa 1936-37.

U.S. Navy Northrop BT-1 dive bombers flying over Miami, Florida, October 1939.

Northrop BT-1, landing at Oakland, California.

U.S. Navy Northrop BT-1 (BuNo 0614) of Bombing Squadron 5 (VB-5) goes into the starboard catwalk during a landing accident aboard the aircraft carrier USS Yorktown (CV-5), circa 1940. Note man in asbestos suit and other members of the flight deck crew running to assist.

A U.S. Navy Northrop BT-1 (BuNo 0631) of Bombing Squadron 6 (VB-6) aboard the aircraft carrier USS Enterprise (CV-6), circa 1940. The yellow color of its wings visible and 'true blue' color of vertical and horizontal stabilizers were assigned to the Enterprise Air Group. The BT-1s were removed from fleet service by 20 April 1941. The BT-1 0631 then served as a training plane and was finally retired on 31 October 1944.

U.S. Navy Northrop BT-1 of bombing squadron VB-6 in flight. VB-6 was assigned to the aircraft carrier USS Enterprise (CV-6).

Northrop BT-1 of VJ-3.

Northrop XBT-1 (BuNo 9745) on 4 December 1936.

XBT-2 (BuNo 0627) prototype on 23 July 1938. This was to be the prototype of the later Douglas SBD Dauntless, although canopy and tail would differ from the XBT-2.

Northrop (Douglas) XBT-2 undergoing handling and drag reduction tests in the Langley 30 x 60 Full Scale Tunnel. This is the revision of the Northrop BT-1 that eventually became the Douglas SBD prototype. At the time this aircraft was produced, Northrop became the El Segundo Division of Douglas.

U.S. Navy Northrop XBT-1 prototype (BuNo 9745) which made its first flight in August 1935.

View taken on the flight deck of the aircraft carrier USS Enterprise (CV-6) showing U.S. Secretary of the Navy Frank Knox inspecting aircraft (Northrop BT-1s). Knox is followed by Admiral James O. Richardson, USN (center). Commander Milton L. Deyo, USN (Aide to SecNav), also is visible, at far right.

Northrop BT-1, aircraft 13 of Bombing Five off USS Yorktown.

Douglas XBT-2, El Segundo, circa 1939.

Liberator Mk.II (AL504) "Commando": Prime Minister Winston Churchill's Personal Transport

Commando (Air Ministry serial number AL504) was a very long range Consolidated Liberator II aircraft adapted for passenger transport, to serve as the personal aircraft of Prime Minister Winston Churchill. Commando disappeared without a trace on 27 March 1945 over the North Atlantic Ocean, while on a flight from RAF Northolt to Lajes Field in the Azores, en route to Ottawa in Canada. The cause of the disappearance of the aircraft remains unknown to this day.

Volunteer pilot William Vanderkloot, a US citizen serving with RAF Ferry Command since June 1941, delivered a specially modified long-range Consolidated Liberator II in July 1942. Vanderkloot was ordered to RAF headquarters, where he was asked by Sir Charles Portal, Chief of the Air Staff, if there was a safe, direct route from England to Cairo, by air in the Liberator which he had just delivered to Prestwick Airport. Vanderkloot informed Portal that the flight was possible with one stop in Gibraltar. Initially heading eastwards from Gibraltar, staying over the sea in the afternoon, and then turning sharply south after dusk, flying over Spanish and Vichy French territory in Africa in darkness, before turning east again for the Nile, approaching Cairo from the south. Thus the danger from land-based enemy aircraft in North Africa and Sicily would be largely avoided without having to fly halfway around Africa.

Portal told Vanderkloot to "stay handy to the telephone". The next day Vanderkloot was taken to Winston Churchill's office, No.10 Downing Street. Churchill, clad in robe and slippers, offered him a drink, beginning a relationship that had Vanderkloot flying the Prime Minister on sensitive diplomatic trips across war-torn Europe, Russia, North Africa and the Middle-East. "He took calculated risks," said his son, William III. "There was a lot more risk in flying back then. It was a frontier, and I think all the old pilots will say it, secretly to themselves, that they enjoyed being on their own. It was the wild blue yonder." As Churchill's pilot, Vanderkloot flew Lord Mountbatten to England in June 1942, conveyed the Prime Minister and Chief of the Imperial General Staff Alan Brooke to Egypt in August 1942 to replace Claude Auchinleck commander of the British Army in North Africa with Bernard Montgomery and also took Churchill to high-level talks in Moscow with Joseph Stalin, to Turkey to determine that country's wartime intentions, and to the Casablanca Conference in 1943.

On delivery Commando had a regular Liberator nose and tail configuration despite the internal modifications but was later converted to have a covered nose and also the same single tail fin used on the Consolidated PB4Y-2. The VIP ("Very Important Person[s]") interior had comfortable seating, an electric galley and even a bed, installed for Churchill. After the second extended trip, Churchill never again flew in Commando, instead switching to Ascalon, an Avro York (a transport aircraft based on the Lancaster bomber, with a larger fuselage) with an all-British crew. Vanderkloot and his mixed US/Canadian civilian crew were all recommended for British awards for their service, he and one other receiving honorary OBEs.

In September 1943 Liberator AL504 was withdrawn from VIP service and flown to a Tucson, Arizona USAAF base, where it underwent major modifications and emerged as a one-off transport, lengthened by seven feet, with single tail fin, extended fuselage, and upgraded engines. AL504 flew again in March 1944 as the trial version of the US Navy’s Consolidated RY Liberator Express transport. Vanderkloot and the crew continued to fly it for a time, one crew member's last logbook entry for AL504 is 24 November 1944.

Commando had served as Churchill's official aircraft during a critical period and later in the war was also used on occasion by other VIP's for their business in connection with the war effort. She also served with No. 45 Group Communications Flight (45 Gp Comms Flt), based at Dorval, near Montreal. It was well maintained and proved extremely reliable and had been flown from Montreal to Sydney, Australia, on 5 November 1944 by Air Commodore C J Powell CBE, RAF (Senior Air Staff Officer) RAF Transport Command.

Commando was the second of 139 VLR (Very Long Range) Liberator II aircraft delivered to the RAF mostly to be used by RAF Coastal Command on maritime patrol duty and anti-submarine warfare, escorting the supply convoys of merchant vessels and attacking and sinking German U-boats.

The Under-Secretary of State for Air Rupert Brabner DSO DSC, his deputy Sir John Abraham KBE CB, and the Air Member for Training Air Marshal Sir Peter Roy Maxwell Drummond KCB DSO & Bar OBE MC RAF needed to fly to Canada with other dignitaries to attend a ceremony marking the closure of the British Commonwealth Air Training Plan. Winston Churchill's former personal transport Commando was assigned as the VIP aircraft.

Flown by Wing Commander William Biddell OBE DFC, the aircraft took off from RAF Northolt at 23:00 hours GMT on Monday 26 March 1945 to fly to Ottawa, Canada, with a refueling stop at Lajes Field in the Azores. Routine contact was established between the aircraft and its base at 05:22 hours GMT in the morning with the flight proceeding as scheduled. The flight was proceeding routinely when the last contact was made with RAF Transport Command at RAF Prestwick at 07:16 hours GMT on the morning of 27 March 1945 in position 40°30'N 20°17'W by civilian Radio Officer Frederick Williams aboard the aircraft, to advise an estimated time of arrival of 08:10 hours at Lajes Field. There were no further signals.

When Commando failed to arrive at Lajes Field emergency calls were made by radio and air-sea searches initiated once the aircraft was classified as overdue. RAF Coastal Command assisted by the Royal Navy commenced a series of searches which were described by Prime Minister Winston Churchill in his announcement in the House of Commons on 28 March 1945. Close to the flight path which Commando would have been following over the ocean in towards Lajes Field aircrew of the searching RAF Coastal Command aircraft spotted some yellow dinghies, a small amount of wreckage and an oil patch on the surface. It was 150–200 mi (130–170 nmi; 240–320 km) north-west of the Azores, there were no traces of any survivors. Little could be done and it was considered probable that Commando had crashed at sea while approaching the Azores.

Possible Causes

Radio or radio navigational aid failure was not considered an issue as the aircraft was flying in daylight and the Azores would probably have been located without difficulty.

Engine failure was considered. The No. 2 engine had been changed during maintenance on 15 November 1944 and had 517 flying hours, the other three engines had each accumulated 466 flying hours and had been serviced on 16 November 1944. The aircraft carried its own flight engineer. Its previous civilian flight engineer, John Affleck, testified at the court of inquiry and reported that mention was made in a radio signal of an oil leak in the No. 2 engine which he believed might have resulted in a fire beside a fuel tank.

Fuel shortage was considered unlikely, excepting a catastrophic leak, as the aircraft carried considerably more than sufficient for its flight to the Azores.

Pilot error was considered unlikely as the aircraft was flown by a highly experienced RAF Transport Command transatlantic pilot who had 635 flying hours on Liberators and 3,780 flying hours in total.

Navigational error was discounted as the traces of wreckage were found close to the expected flight path.

Structural failure was considered, but was not confirmed due to lack of evidence from crash debris.

The Crew

Pilot: Wing Commander William Hugh Biddell OBE DFC RAF, aged 28, a married man from Kent, was a regular service officer who had joined the Royal Air Force and been commissioned on 21 October 1935, promoted to flight lieutenant on 3 September 1939 serving as a flight commander in No. 206 Squadron RAF (206 Sqn) on maritime reconnaissance and anti-shipping duties. He was awarded a Distinguished Flying Cross on 14 June 1940 for bravery in combat with enemy aircraft over the Dunkirk evacuation beaches in May 1940. and also received a "Polish Cross for Gallantry" the same month for having flown the Polish General Wladyslaw Sikorski from Bordeaux to England escaping the German occupation forces. Biddell joined the staff of RAF Ferry Command on 22 January 1942, was promoted to temporary Wing Commander on 1 June 1942, and decorated as an Officer of the Order of the British Empire Military Division on 8 June 1944 for his work with RAF Transport Command.

Second Pilot: Flight Lieutenant Aubrey Norman Brodie RAFVR aged 24, from Birmingham, had joined the RAFVR in 1941, learned to fly in Canada and been commissioned 9 December 1943. He was rapidly promoted Flying Officer in June 1944 and then acting flight lieutenant.

Navigator: Flight Lieutenant David Buchanan RCAF aged 29, a married man from Winnipeg, Manitoba. He was a highly experienced Navigator with RAF Ferry Command who had flown on many trans-atlantic flights.

Second Navigator: Flight Lieutenant Kenneth George Shea RAAF aged 27 born at Launceston, Tasmania, he had taken part in many long range missions from Dorval, initially with RAF Transport Command and since 1 March 1945 with No. 231 Squadron RAF (231 Sqn) still involved in trans-atlantic flights. Promoted to Flight Lieutenant in February 1944 he had been awarded a King’s Commendation for Valuable Services in the Air on 1 September 1944.

Radio Officer: Mr. Frederick Walter Williams, a civilian, employed by RAF Transport Command aged 32 from Gloucester, Gloucestershire.

Flight Engineer: Warrant Officer Douglas James Spence (RCAF) aged 33 from Vancouver, a regular service RCAF flight engineer with 17 years' service who had flown the trans-atlantic route many times. He was posthumously commissioned.

Flight Steward and Clerk: Mr. Victor Ian Claud James Bannister, a civilian employed by RAF Transport Command aged 29, a married man from London.

The VIPs

Commander Rupert Arnold Brabner DSO DSC Royal Navy: (Parliamentary Under Secretary of State for Air) A 33-year-old married man. Brabner was an M.A. graduate of Cambridge University, elected Member of Parliament for Hythe, Kent and a serving Fleet Air Arm ace fighter pilot. He was born in Chelsea, London, on 29 October 1911. Educated at Felstead School, Essex and St. Catharine’s College, Cambridge and was an elected member of London County Council and then Conservative Party Member of Parliament from July 1939. He was decorated for his success as a Fleet Air Arm fighter pilot for actions over Malta. Brabner was "Technical Assistant" to the Fifth Sea Lord at the Admiralty 1943–44 and then "Assistant Government Parliamentary Whip" before being appointed Under Secretary of State for Air in November 1944.

Air Marshal Sir Peter Roy Maxwell Drummond KCB DSO & Bar OBE MC RAF: Air Member for Training

Sir John Bradley Abraham KBE CB: (Deputy Under Secretary of State (Air Ministry)) A 63-year-old married man from Radlett in Hertfordshire. Abraham joined the British Civil Service as a Boy in 1897, progressing to Class I Clerk at the Admiralty in 1912, and then "Assistant Principal Clerk" (Air Ministry) in 1918. Appointed a Companion of the Most Honourable Order of the Bath in January 1933 as Assistant Secretary of State at the Air Ministry. He was Knighted on 1 January 1942.

Mr. Henry Albert Jones CMG MC Croix de Guerre with Palm: (Air Delegation (Washington) and United Kingdom Air Liaison Mission (Ottawa)) A 51-year-old married man from Chingford. Jones had served in World War I with the Wiltshire Regiment and as an observer with the Royal Flying Corps being awarded a Military Cross for conspicuous gallantry in France, and also a Croix de Guerre 1914-1918 with Palm. After military service he was Gazetted to the Department of Overseas Trade as an "Intelligence Officer". Jones was British government official air historian and author of 31 published works documenting the official story of the war in the air 1914–18. He was seconded to the Cabinet Office in the 1930s and then to the Air Staff Secretariat in 1939, becoming Director of Public Relations (Air Ministry) in 1944. He was appointed a Companion of the Most Distinguished Order of St Michael and St George on 1 January 1943.

Mr. Edward Twentyman: (Civil Service) A 57-year-old married man from Chatham, Kent, born at Bolton, Lancashire, educated at London University. Worked in the India Office from 1910 and as "Principal Assistant" at the Treasury in 1920.

Mr. Eric Robinson: (Civil Service) A 35-year-old married man from Southport, Lancashire, living in Bromley, Kent.

Squadron Leader Elisha Gaddis Plum RAFVR: (UK Air Liaison Mission) A 47-year-old married man resident in Chelsea, London, and Rumson, New Jersey, a US citizen working with the United Kingdom Air Liaison Mission. Gaddis Plum joined the RAFVR and was commissioned on 1 June 1940 as a Pilot Officer in the "Equipment Branch", he was promoted Flight Lieutenant on 11 June 1943 and acting Squadron Leader.

Further Reading

Andrade, John M. (1997). U.S. military aircraft designations and serials 1909 to 1979. Leicester: Midland Counties Publications.

Birdsall, Steve (1968). The B-24 Liberator. New York: Arco Pub.

Birdsall, Steve (October 1979). B-24 Liberator in Action – Aircraft No. 21. Carrollton, Texas: Squadron/Signal Publications.

Birdsall, Steve; Color illus. by Preston, John (1973). Log of the Liberators : an illustrated history of the B-24 (1st ed.). New York: Doubleday & Company, Inc.

Blue, Allan G. (1976). The B-24 Liberator : a pictorial history. London: Allan.

Bowman, Martin (1979). The B-24 Liberator 1939–1945. Norwich (33 Oxford Pl., Norwich): Wensum.

Bowman, Martin (2003). B-24 Liberator. Shrewsbury: Airlife Pub.

Brookes, Andrew (1992). Disasters in the air (repr. impr. ed.). Shepperton, Surrey: Ian Allan.

Davis, Larry; color by Greer, Don; illustrated by Manley, Perry (1987). B-24 Liberator in action Aircraft No. 80. Carrollton, Tex.: Squadron/Signal Publications.

Freeman, Roger A. (1983). B-24 Liberator at war. London: Ian Allan.

Lavery, Brian (2008). Churchill goes to war : Winston's wartime journeys. London: Conway Maritime.

Livingstone, Bob (1998). Under the Southern Cross : the B-24 Liberator in the South Pacific (Limited ed.). Paducah, KY: Turner Pub.

O'Leary, Michael (2001). Consolidated B-24 Liberator. Oxford: Osprey Aviation.

Robertson, compiled by Bruce (1987). British military aircraft serials, 1878–1987 ([6th rev. ed.]. ed.). Leicester: Midland Counties Publications.

Shacklady, general ed.: Edward (2002). Consolidated B-24 Liberator. Bristol: Cerberus.

Shores, Christopher (1986). History of the Royal Canadian Air Force. London: Bison Books.

Churchill's Consolidated Liberator Mark II (AL504) "Commando" (painted black) parked at RAF Nicosia with the familiar shape of the Kyrenia Mountains in the background.

The Consolidated Liberator Mark II (AL504) "Commando" was not pressurized and rarely flew above 8,000ft.

On 1 February 1943 Churchill leaves Cyprus bound for Tripoli. He boards the aircraft via a small door at the rear.



The Prime Minister's aircraft, Consolidated Liberator Mark II (AL504) "Commando", VIP transport aircraft of No. 24 Squadron RAF, taxiing at Lyneham, Wiltshire, with Winston Churchill and the Chiefs of Staff on board, after returning from the Casablanca Conference, January 1943.

The Prime Minister, Winston Churchill in RAF uniform, accompanied by Air Chief Marshal Sir Charles Portal, Chief of the Air Staff, leaving Consolidated Liberator "Commando" of No. 24 Squadron RAF at Lyneham, Wiltshire, on their return from the Casablanca Conference. 24 Squadron provided VIP transport for the Prime Minister and Chiefs of Staff during the conference and their subsequent tour of the Middle East. January 1943.

Prime Minister Winston Churchill's luggage being unloaded from "Commando", his personal Liberator II transport aircraft, after the Casablanca Conference of January 1943.

Winston Churchill climbing out of his Liberator Mark II (AL504), "Commando", that flew him to Moscow.

Prime Minister Churchill, who has been greeted by the Soviet Foreign Minister Molotov on arrival at Moscow airport, stands bareheaded while Red Army bands play the national anthems of Britain, the USA and the USSR, 12 August 1942. William Averell Harriman, the U.S. special envoy to Europe; Vyacheslav Molotov, the Soviet Foreign Commissar; and Boris Shaposhnikov, the Soviet Deputy Defence Commissar, are on the Prime Minister's right. Behind them part of the tail is visible of the Liberator Mark II in which Mr Churchill flew to Moscow can be seen.

Vyacheslav Molotov, the Soviet Foreign Commissar; Boris Shaposhnikov, the Soviet Deputy Defence Commissar (behind Molotov); William Averell Harriman, the US special envoy to Europe; and Winston Churchill at Moscow airport, 12 August 1942.

The extra cabin fitted in LB-30 Liberator (AL504) "Commando", the personal transport aircraft of the Prime Minister, photographed at Northolt, Middlesex, on returning to the United Kingdom, following extensive modification and a complete overhaul by the Consolidated Aircraft Company at San Diego, California. The fuselage was extended by seven feet to accommodate an extra cabin and table for the Prime Minister, shown here.

The main cabin interior of LB-30 Liberator (AL504) "Commando", the personal transport aircraft of the Prime Minister, photographed at Northolt, Middlesex, on returning to the United Kingdom, following extensive modification and a complete overhaul by the Consolidated Aircraft Company at San Diego, California. The fuselage was extended by seven feet and the interior was furnished to accommodate 20 passengers with bunks and a stewards galley. This view shows the main cabin with the bunks stowed.

Liberator Mk.II (AL504) "Commando". The picture shows the aircraft in its twin single-fin and rudder configuration and lack of camouflage paint.

Liberator Mk.II (AL504) "Commando". The picture shows the aircraft in its later single-fin and rudder configuration and lack of camouflage paint.

Liberator Mk.II (AL504) "Commando".

Liberator Mk.II (AL504) "Commando", this Liberator emerged from Consolidated’s modification facility in Tucson, Arizona, with many of the features of a long-bodied RY-3 transport version.

At a London airfield, exiled Dutch Queen Wilhelmina greets her daughter Juliana who returns from her safe house in Canada, VVIP enough to use Churchill's personal LB-30 Liberator II (AL504) "Commando", 9 September 1944.

LB-30 Liberator (AL504) "Commando", in flight over Canada, November 1944. One of the original aircraft ordered by the Anglo-French Purchasing Commission in the United States and taken over by the British after the fall of France, AL504 became the personal transport of the Prime Minister, Winston Churchill, who flew in it to many of his wartime conferences. AL504 was originally a standard Liberator Mark II, which was later modified by lengthening the fuselage and fitting a large single fin and rudder, as seen here. It was operated by the Communications Flight of No. 45 (Atlantic Transport) Group, Transport Command. AL504 disappeared over the South Atlantic while flying from the Azores to Ottawa, Canada, on 26 March 1945.

Air Marshal R M Drummond, Deputy Commander of the Royal Air Force in the Middle East, seated at his desk. One of the VIPs onboard "Commando" when lost in March 1945.