Sub Depots and Air Service Squadrons

Guys, hopefully someone can help me with a slight nudge in the right direction!
 
I'm strugling with terminology, and I'm trying to work out the time line for change over to the Sub Depot system in the 8th AF in England during WW2.
I believe I'm correct in saying Sub Depots came from Air Service Squadrons, which were the first groups allocated to the UK for aircraft maintenance at group level.
 
In the Official Guide to the AAF, (page198), it refers to several groups under the 'base maintenance unit' title, airbase squadrons, airways detachments and airdrome squadrons. Were these groups all fairly similar and undertaking similar roles?
Also, was the Sub Depot term in use in the US prior to the WW2, or was it a new type of unit the grew from the requirements of combat?
 
If I'm way off mark, perhaps someone could explain the organisational structure for aircraft maintenance, with regard to the 4 echelons of servicing, both in a peactime and combat situation
 
Thanks again for any help
 
Malc, in soggy wet England!

Malc - a reply from soggy, wet, HOT Tennessee (LOL)
 
   During the past year I was given numerous AAF documents in conjunction with a contract I had with the Department of Justice in a on-going court case.  One of these documents was a 2nd Air Force processing directive defining the levels (echelons) of maintenance at Herington AAF in 1945.  The tasks associated with each level are given below
   I found that the overall level of definitions published by 2AF to be somewhat out in never-never land when compared to what my squadron, the 54th Strat Recon Sq (Med) Weather practiced on our flight line. So, after each 2AF task I have put, in italics, where the 54th did each of those tasks
 
T.O Description
of Echelon Work
 
FIRST LEVEL - DONE ON RAMP
    Daily and Preflight Inspections - Yes
    Servicing - Yes
    Clear Form 1 Write-ups - Yes
    Spark Plug changes - Yes
    Engine Run-ups - Yes
SECOND LEVEL - DONE IN HANGER
    Inspections 25, 50 and 100 Hour - On the hardstand, sometimes in nosedock if available.
    Cylinder changes - On the hardstand
THIRD LEVEL - SUB DEPOT HANGER
    Engine changes - On the hardstand
    Major skin repairs - Some done by our dedicated sheet metal people on the hardstand, large jobs done by base shops.
    Replace control surfaces - on the hardstand.
    Propeller change - on the hardstand by squadron prop people.
FOURTH LEVEL - DEPOT TASKS, NOT AT HERINGTON
    I seem to remember that the crew of the plane next to us hauled it to the nose dock and changed the fuel cells in the wings after inadvertantly putting 145 octane in the tanks in place of the normal 130.
 
     As you can see, we did all three Levels of maintenance right out on the ramp on the hardstand, and possibly the Fourth.  Second AF seemed to have people writing their maintenance procedures who never left their office to see what was happening in the real world.
    For example, a 2AF Engine Change document said that "a well-trained crew of nine men could change a R-3350 engine in twelve hours."
    When I read that I called two former 54th mechanics and read the statement to them.  When they stopped laughing we all agreed that, in the 54th, THREE men would change an engine in 7 - 8 hours.
    In my experience, three years on the line maintaining WB-29 aircraft, there would have to be a most compelling reason for a crew chief to turn his airplane over to Sub-Depot people, about whose capabilities he knew nothing, for something as simple as a engine change.
    You could end up with more problems than when you started.  Example: We had pulled our plane into the squadron nose dock for a 100 hour inspection.  The nose dock crew was to do all the engine work while our plane crew took care of the Airplane-General requirements.
    Fast forward a month to the next 50 hour inspection.  Pulling the spark plugs for scheduled replacement, I came to one that would not turn.  My crew chief and I put a leverage enhancer (four foot length of pipe) on the end on the hinge handle  and had at it.  When the plug finally came out, it came out with the cylinder insert attached.  One of the dummies in the nose dock, for whatever reason, had not put anti-sieze compound on the spark plug - which gave us a 10 - 12 hour cylinder change instead of a 10 - 12 minute plug change.
 
   One last chuckle, if you will.  The above mentioned Engine Change document went on to descfribe what each of the nine man change crew would be doing.  I almost choked on my coffee when I read about man number seven:  "This man must be small of stature so as to be able to climb through the access door and work on the rear of the engine."  Yeah - maybe if he was two foot nothing he could lay on the hoses and 'work' horizontally.  But stand up in there?  Impossible.
   Loved the reaction of a friend when I read that paragraph to him.  "You remember the knock we had in #2 engine?  I bet we locked that little rascal in the nacelle and that was him trying to get out!"
 
Bob Mann

Here is an excerpt from a book called "Tactical Services in the AAF", dealing with Sub Depots:

In 1941 an entirely new element of command was introduced into air force logistical organization with the establishment on the 15th of March of the Provisional Air Corps Maintenance Command as a part of the Material Division of the Air Corps.  This organization was headed by Colonel Henry J. F. Miller, with Lieutenant Colonel Elmer E. Adler as Chief of Staff.  On 24th of April the word "Provisional" was dropped, as the new command was considered to have passed the trial period.
In the beginning the Maintenance Command consisted of a Headquarters, the Field Service Section (of Material Division), the 50th Transport Wing, and six air depots, which were situated at Fairfield, Ohio; San Antonio, Texas; Sacramento, California; Middletown, Pennsylvania; Ogden, Utah; and Mobile, Alabama.  In addition there was established the Fairfield Maintenance Group Area and the San Antonio Maintenance Group Area, each consisting of a control depot and several well-established Air Corps sub-depots.  At the bases where these designated sub-depots were located, station engineering and supply activities passed to the control of the Maintenance Command at the time of its activation.  Existing relationships between GHQ Air Force stations and the control depots were not altered until January 1942.
Thus, the Maintenance Command system at first applied only to a few bases under the jurisdiction of the Chief of the Air Corps.  For several months the GHQ Air Force (Air Force Combat Command) continued to perform its own first, second, and occasionally third echelon work at establishments at GHQ Air Force stations.  It was during this period, early in 1941, that the Air Base Groups were organized by GHQAF at a number of bases in the continental air forces.
Meanwhile, the Maintenance Command activated four new mobile units, called Air Depot Groups, to accompany combat units overseas and to perform second and third echelon functions.  And on 28 August 1941 the Maintenance Command began the installation of civilian sub-depots, with commissioned officers in charge, to perform third echelon maintenance and supply at all domestic stations under the direct control of the Chief of the Air Corps.  The presumption was that sooner or later sub-depots would be established throughout the air forces.
The GHQAF did not concur in plans to establish sub-depots at bases of the numbered air forces and succeeded in postponing the establishment of sub-depots at GHQAF bases until January 1942.
On 17th October 1941, the Maintenance Command was redesignated the Air Service Command and assumed responsibility for third and fourth echelon maintenance and supply for the Army Air Forces.  On 11th December 1941 the new service command was released from the jurisdiction of the Material Division and assigned directly to the Chief of the Air Corps.
Under the reorganization of 9th March 1942, the Air Service Command was assigned directly to the Headquarters, Army Air Forces.  On 22nd June 1942, all Air Base Groups in the continental U. S. were redesignated Service Groups and transferred to the jurisdiction of the Air Service Command.  Thereafter Service Groups remaining in this country were trained by ASC to perform in the theaters of operations the same third echelon work as that accomplished by sub-depots in this country.  Air Depot Groups, ultimately, assumed responsibility for fourth echelon functions overseas, which had been performed by air depots in the U. S.

Maintenance echelons were defined by AAF Regulation no. 65-1;
First echelon maintenance is performed by air elements of combat units.
Second echelon maintenance is performed by ground elements of combat units, or by Air Base Squadrons, or by Airways Detachments.
Third echelon maintenance is performed by Service Groups or Sub-Depots.
Fourth echelon maintenance is performed by Air Depot Groups or air depots.

I believe the Sub-depot system replaced Service Groups in the 8th Air Force Bomber Divisions in November 1943, but the VIII Fighter Command and VIII AF Composite Command continued using Service Groups until the end of the war.

Mark

Bob, Mark,
 
Thanks guys, thats just what I was after!
 
 Malc

As Mark mentioned, VIII Bomber Command was the only overseas command to adopt the Sub Depot system to replace Service Squadrons (15 Nov 43).  Service Squadrons had the same mission, but were (at least theoretically) mobile.  VIII Bomber Command groups operated from fixed bases from 1943 until the end of the war.  Because of the lack of a mobility requirement, Sub Depots in the US were partly manned by civilians.
 
It appears that while some of the Service Squadrons were disbanded, others were kept as paper units and then transferred to Ninth AF as its operational units arrived in the UK.

Bernie Shearon
Push the stick forward, the houses get bigger. Pull the stick back, the houses get smaller (unless you keep pulling -- then they get bigger again)

I have something like 40 A.A.F. station directories that list field, sub-depots, and ranges. I am currently doing a research paper in the field that gives me my sn, and in the states at least, they seem to have been seperate units, with the the third echelon designation replacing the sub-depot one...sometime before june of 1945. It may appear earlier, however I draw the line at 3am. The 3rd echelon repair shops were listed as formerly being sub-depots. Lubbock's sub-depot had it's own seperate commander, at least in the beginning. They may have refered to them differently in england, I do not know, but in the continental U.S. the sub-depots became 3rd echelon repair shops. There does not seem to be a listing for the other two, unless they became a specialized depot, or one of the other types listed. There are no indications similar to the sub-depot listing that mentions any other renamings in the directory I am looking at though. Scott Murdock might know though. He runs a site that I shall not mention because I do not want to be banned on my first post, however if he is around here, he is very knowledgable on the subject, and may know more. Actually he gave me the listings I have, so....long and semi-productive?

In re sub-depots in the continental US, I can refer you to "The Maintenance of Army Aircraft in the United States, 1939 - 1945." Army Air Forces Historical Study No 51., AAF Historical Office, August, 1946.
Chapter III, Subdepot Control is footnoted:  "The present account of subdepots deals principally with the administraive history and the maintenance activities of these instalations."
 
That given, the Chapter, for twenty-seven pages goes into a detailed history of the evolution and functions of the subdepots.  My interest is focussed on the subdepots at the B-29 processing bases and their role in the processing of the B-29's for overseas movement.
If you have questions on the subdepot functions and (directed) resposibilities, and do not have access to the document, I would be happy to do a look-up.
 
Bob Mann 

Rambertsan


In re sub-depots in the continental US, I can refer you to "The Maintenance of Army Aircraft in the United States, 1939 - 1945." Army Air Forces Historical Study No 51., AAF Historical Office, August, 1946. . . . If you have questions on the subdepot functions and (directed) resposibilities, and do not have access to the document, I would be happy to do a look-up.

Or, since postage has gone up , it is available as a .pdf at:

http://afhra.maxwell.af.mil/numbered_studies/studies2.asp

Also, researching Depots and Sub Depots can get confusing because the terms are used to describe both installations (Scott Murdock's specialty) and units.  The units in the US were assigned geographically to Air Depots (later to Air Depot Control Area Commands, then Air Technical Service Commands) until 1 Jan 44 when they were transferred to the command operating the base (1-4 Air Force, AAF Training Command, I Troop Carrier Command) until the spring of 1944 when they were absorbed into the AAF Base Unit on the base).

Bernie Shearon
Push the stick forward, the houses get bigger. Pull the stick back, the houses get smaller (unless you keep pulling -- then they get bigger again)