Route from England to Poland over North Sea , over Denmark and Baltic Sea was extremely dangerous and heavily "polluted" with German AA Flak batteries and night fighters.
The B-24 Liberators used for those flights were heavily modified D models ( later in 1944 from 15 USAAF B-24 J models ) Modifications included removal of the belly turret, nose gun turret and equipment unnecessary for the mission, such as oxygen system and equipment,heating installation, radio gear was removed, ( IFF ect. ) in order to lighten plane and provide more cargo space. The rear Bolton turret with four 303 guns and top turret with twin Browning .50 guns were kept as protection from German night fighters but flash suppressors had been put on the remaining weapons and flame dampeners were put on all four Pratt & Whitney R1830 turbo-superchargers. ( in order to improve forward visibility some B24 J models operated by Poles had whole front turret chopped off and replaced with "green house" glazed nose from B-24 D )
Agents ( were drafted from all services of Polish Air Force and Army and they had been trained in 1st Polish Para Brigade facilities in Scotland )
Canisters with supplies were dropped by parachute through the opening left by removal of the belly turret, blackout curtains had been installed over all pilot and navigator windows and rear side gunners openings.
In addition, supplies were loaded into containers designed to fit inside the bomb-bay and released from there by the existing equipment. In order to accommodate standard British supply canisters ( used by British paratroopers ) USAAF standard bomb "mounting points" have been replaced in bomb bay by British one. The main fuel system consisted of 18 fuel cells ( tanks ) in both wings.And to increase range of the B-24 two Rubberized extra long range tanks were installed in forward bomb bay.
Average distance to drop zone in Poland was between 850-950 miles one way and plane had to circle sometimes for 15-25 min and if no signals on the ground were present then they will have to fly to another drop location. So those extra tanks in bomb bay were crucial to planes safe return to base but were extremely vulnerable to small caliber ground fire and AA Flak.
Targets were given by exact longitudes and latitudes and special recognition light signal patterns were developed ( unique to each mission and each drop zone on given day ) thus making precise navigation imperative. Crew after exchange of light signals with ground crew start descent to drop zone.
Typical RAF B-24 crew consist of :
1st pilot
2 nd pilot
Navigator/ Radio operator
Dispatcher
Flight Mechanic
Top Gunner
Rear Gunner
All flights were made on full moon nights ( crews flew tree to four nights in the row then they waited for next full moon ) It was especially important so that visual navigation could be made by using existing railroad tracks, towns ,roads ,rivers, lakes as check points. The pilot, and dispatch/navigator all had maps to aid them in keeping track of their current location, whilst the navigator kept position by dead reckoning, with all staying in close inter-phone contact.
Each flight was unique and individual, and each navigator had his own favorite route to the target and in many cases different return route. Quite often they had to plot a route to avoid near by Luftwaffe bases and AA Flak locations.( Luftwaffe had allocated a special train with FuSE 65 E FuMG65E Würzburg-Riese radar station in Denmark and southern Poland to deal with those flights ) On flights to targets in Poland the aircraft crossed the Adriatic coast in Croatia at around six thousand feet to avoid anti aircraft fire from German AA ships on the Adriatic Sea and Yugoslav Dalmatian coast , then plane dropped to five hundred feet or so to avoid night fighters in Hungary. Once inland they race across Hungary over Danube river and when they reached Tatra mountains they had to climb again to 6000 feet to cross over mountains on Polish/ Slovakian border and then drop again down to 500 feet or less and follow the map to drop zone and to make it possible to verify location at all times, assuring that above mentioned raiload tracks,rivers,lakes ect. checkpoints on the ground corresponded exactly to the area being looked at in the pilots cockpit and glazed nose of the aircraft.( Very stressful task and during Warsaw Up Rising in August 1944 they flew all way north along Vistula river. And on approach to Sulejow ( suburbs of Warsaw) about 20 miles south from capitol burning city was so visible that provided additional aid in navigation.When plane reached bridges over Vistula in Warsaw they made 90 degrees turn and delivered supplies from roof top hight to waiting partisans.
Other vise on regular supply flights to Poland ( Polish Underground Army AK- Armia Krajowa) when only a few miles from the target area all available crew members began searching for the drop zone and recognition lights. ( different patterns on different drop zones) Coming towards the target, the aircraft slowed down to 120-130 mph and dropped from an altitude of four hundred feet or less ) Agents were always dropped first, with supplies ( canisters ) on a second run , and packages and packets on third and if needed fourth drop. Often, pilot had to fly plane several miles farther into enemy territory after completing their drops to disguise the actual drop location should any German units been present in vicinity and recognize the aircraft's turning point as the drop location.
First flight of B-24 to Poland and first casualty was airframe B-24D-10-CF-27-42-63881
GR - F ( BZ 858 ) RAF MK.III
Operation " Cottage 7 "
On night of 9 / 10 October 1943 -
Crew was dispatched from Tempsford UK to fly over North Sea , Denmark , Baltic Sea to Poland with supply mission to drop zone Baran 511( about 25 km South West of town of Lublin in eastern Poland )
Crew made successful drop at allocated drop zone and on the way back to England plane sustained heavy damage from German AA Flak ship in Baltic Sea off coast of Sweden -with leaking fuel and gear partially down (due to leaks in hydraulic system ) pilot made decision to abandon ship - entire crew bailed out over neutral Sweden.
Warrant /Officer Bolesław Hułas -1 pilot
Fl/Lieutenant Czeslaw Nowacki -2 pilot
Fl/Lieutenant Mieczyslaw Malinowski -navigator
Fl/Sgt. Bolesław Wozniak -dispatch
Fl/Sgt. Stefan Miniakowski -gunner
Warrant /Officer Józef Dubiel -gunner
Sgt. Witold Ruciński -flight mechanic
and all been interned In neutral Sweden ( to be continued )