LAB-equipped Liberator GR VIII aircraft for Coastal Command ASW

[WATU]

During early 1945 some Coastal Command ASW squadrons re-armed with LAB-equipped Liberator GR VIII aircraft. They had Mk X radar, Leigh Lights, Mk III LLBS and sonobuoys (High Tea) making them state of the art day and night ASW aircraft.. An example was 206 squadron which was withdrawn from operations from 2/3/45 to 21/3/45 for re--fitting and training. The 206 ORBs subsequently always refer to the Libs as being LL (Leigh Light) and LAB.
My question is whether there is a source which says which Libs and squadrons were LAB-equipped in the ETO during WW2? Beyond that any other sources on Coastal Command and LAB would be of interest. I do have some TNA mentions but patchy stuff.

 

[EwenS]

During early 1945 some Coastal Command ASW squadrons re-armed with LAB-equipped Liberator GR VIII aircraft. They had Mk X radar, Leigh Lights, Mk III LLBS and sonobuoys (High Tea) making them state of the art day and night ASW aircraft.. An example was 206 squadron which was withdrawn from operations from 2/3/45 to 21/3/45 for re--fitting and training. The 206 ORBs subsequently always refer to the Libs as being LL (Leigh Light) and LAB.
My question is whether there is a source which says which Libs and squadrons were LAB-equipped in the ETO during WW2? Beyond that any other sources on Coastal Command and LAB would be of interest. I do have some TNA mentions but patchy stuff.

Firstly, Liberator GR.VIII only began to be delivered in Aug 1944. The earliest batch were serialled KG959-966 & KG979-989. All arrived at Prestwick for modification by Scottish Aviation Limited that month. LAB equipped aircraft seem to have come later but I've no information to hand to tie individual serial numbers to LAB equipped aircraft. You may find that in the ORBs of the following squadrons who received the GR.VIII in the following order:-

224 squadron.
Received its first two GR.VIII on 27 Nov 1944 (KG979 & KG981). It withdrew from operations to re-equip with the GR.VIII between 4 Dec 1944 & 6 Jan 1945, becoming the first CC squadron with the new model, but it seems to have been March 1945 before the last of its old GR.VI aircraft departed. After the end of the war in Europe several new LAB equipped aircraft were allotted to the squadron.

120 squadron (Dec 1944)
Received 14 GR.VIII in Dec 1944 & another in Jan 1945. First GR.VIII sortie was on 19 Jan 1945.


53 squadron (Jan 1945)
Received its first 4 GR.VIII on 14 Jan 1945 followed by another 13 in the first 10 days of Feb 1945. It still had a couple of GR.VI on strength at the end of April.

86 squadron (Feb 1945)
Traded its GR.V for GR.VIII in Feb 1945 (13 on hand by 11th Feb and 15 by 'VE Day) flying its first sortie with the new model on 2 March 1945.

206 squadron (Feb 1945)
Began receiving GR.VIII with the full LL, AN/APS-15 (ASV Mk.X) & LAB fit at the end of Feb 1945. Withdrawn from ops to re-equip 2-21 March 1945, flying its first GR.VIII sortie on 22 March. Last GR.VI left in early April.

59 squadron (March 1945)
15 GR.VIII aircraft allotted in March with KH & KK serials equipped with LL, AN/APS-15, LAB and "High Tea" sonobuoys. First sortie 23 March. Last GR.V left before the end of April.

547 (March 1945)
First 2 GR.VIII received on 17 March 1945. These were LAB equipped. 6 more received by the end of the month with first sortie on 25th April. By 21 May it had 7 GR.VI and 10 GR.VIII, the latter all with KK serials.

111 (Coastal) OTU
Received 16 GR.VIII in 1945 while in the Bahamas and on return to the UK it received 24 LAB equipped aircraft in Sept 1945.


No mention of LAB except as noted above.

RAF Official Narrative Vol 5 might be of interest

https://www.raf.mod.uk/what-we-do/our-history/air-historical-branch/second-world-war-campaign-narratives/raf-in-maritime-war-vol-v-the-atlantic-and-home-waters-the-victorious-phase-june-1944-may-1945/

Internally, the GR.VIII was laid out differently for its crew of 10 or 11.

Cockpit lhs - captain (1st pilot)
Cockpit rhs- 2nd pilot
Flight deck behind captain facing aft - navigator. Sometimes a second navigator would be carried.
Flight deck behind 2nd pilot facing aft - radar operator (secondary role as air gunner). Usually a second radar operator was carried to she the workload.
Nose - navigator table remained but was used by the LAB operator when fitted
Nose - front gunner
Command deck above rear bomb bay - radio operator
2 or 3 air gunners in rear fuselage to man waist guns an tail turret.

 

[WATU]

Thanks Ewen, great stuff. I had looked over all the CC Squadron logs I hold for 1945. Being too casual I missed the references to LAB for 59 Sqn. For 547 Sqn I had not downloaded the 1945 logs for some forgotten reason so was not aware of them having LAB equipment. I noted that 59 Sqn ceased LAB training on 28/5/45 but no reason is given.
Cheers, Paul

 

[DDonSS3]

As a retired Cold War ASW guy (P-3s, 1975-95), I wonder where the sonobuoy operator station was located. Or did one of the RADAR operators take care of that? Or am I misunderstanding something and that was the LAB operator?

 

[EwenS]

LAB was the AN/APQ-5 set which was connected to the main radar in the aircraft. THe USAAF started using it in Sept 1943 in the Pacific with the 868th BS - see the Wright Project.

DESCRIPTION:	Bombing attachment to microwave ASV sets and Norden bombsight. Set is equipped with an expanded B scope, with range sweeps of 1 and 10 miles.
USES:	designed for low altitude (65-4000 ft.) blind bombing of marine targets. Does not interfere with use of Norden bombsight in visual bombing.
PERFORMANCE:	Automatically releases bombs on isolated radar target selected and tracked by bombardier on AN/APQ-5 indicator. Average bombing error from center of target from 1000 ft. altitude: range ± 75 ft., deflection ± 125 ft. A bombing run up to 10 miles may be used.
TRANSPORTABILITY:	Packed in 4 boxes, weighing a total of 200 lbs.
INSTALLATION:	Permanently installed near gyro stabilizer and electrically connected to ASV equipment in heavy bombers equipped with microwave ASV. Installed weight is 125 lbs.
PERSONNEL:	Bombardier must have additional training on operation of AN/APQ-5. Radar operator and mechanic normally assigned can perform other functions.
POWER:	Requires 350 watts at 110 v 400-800 cycles AC from power supply for basic ASV equipment, plus about 25 watts of 28 v DC.

https://www.ibiblio.org/hyperwar/USN/ref/Radar/img/Radar-p76.jpg

The "High Tea" sonobuoy installation was, AIUI, completely separate from the radar and LAB equipment and operators. Exactly where in the Liberator GR.VIII it and its operator were located I don't know. But considering it relied on reception of radio transmissions from the buoys themselves, he may have been located alongside the radio operator on the command deck above the aft bomb bay.

The RAF GR Liberators were heavily modified to suit them for their role with a lot of standard B-24 equipment removed. The GR.VIII seems to have been modified even further and I've never seen a schematic of their internal layout. I've not even seen an installation on a Sunderland which is the other RAF type known to have carried sonobuoys.

 

[WATU]

LAB II or AN/APQ-5B was the version fitted to the GR VIII's allocated to Coastal Command. ASWDU trials in 1945 rated the LAB II as better than the LAB I but it used a different radar and it is not clear to me (yet) how much of the improvement was the LAB and how much was the radar. Both benefited from improvements, A ten mile approach would have brought Coastal Command out in hives with location of U-boats, especially schnorkels, being at much shorter ranges. The visual sight for low level was the angular velocity Mk III with the Mk T1 (US engineered Mk XIV) as the alternative sight for medium level - essentially above 1,000'.

I agree with Ewen about the High Tea receiver (AN/ARR-3). It was essentially a standard radio receiver modified to pick up the six frequencies of the six buoy colours. I have looked at Coastal Command usage but I don't recall any internal aircraft layout diagram. Given it was a radio receiver listened to via headphones the logic says that it was installed as part of the normal radio fit. That would tie in with power supply and the general WOP abilities. Proximity to a navigator maintaining a tactical plot would have been beneficial. No external vision was needed, it was purely audio. In the dial image you can see three of the six buoy initials.