Technician Badge AP Powerplant

Bob, that is what the bar is for.  The AP Powerplant bar would be for qualifying in powerplant repair generally, then specializing in carb. / intake systems of those powerplants.

From AAF Manual 35-0-1     Revised through July 1, 1945

MOS 956   Airplane Carburetor Repairman

  Makes flow test and performs third and forth echelon maintainence of airplane carburetors.
  Disassembles, inspects, repairs, replaces parts, reassembles and adjusts all float and pressure airplane carburetor units such as fuel control, water injection systems, airflow, automatic mixture control and diaphragm acceleration pumps.
 Completion of course in airplane carburetor overhaul at an Army school or equivalent experience required.



If he was an instructor in the AAFTTC, he may have had a " higher " title than the above ( which I am unaware of, except " Instructor " ), but that would be the MOS of the guys he would have taught. 

From same manual :

MOS 750    Airplane Maintenance Technician

Airplane Crew Chief
Airplane Flight Chief
Airplane Inspector ( 1st and 2nd Echelon )
Airplane Line Chief

 Supervises the inspection, maintenance, adjustment, and minor repair of aircraft and aircraft equipment.
 Performs prescribed inspections of aircraft to determine necessary servicing, adjustments, or parts replacements. Determines priority of jobs, and assigns crews or individual specialists to tasks. Thoroughly checks maintenance work to assure proper condition of aircraft. Warms up engines and taxies airplanes. Checks weight and balance computations of flight maintenance gunner. Instructs subordinates in interpretation of technical orders and in maintenance methods.
 Analyzes and troubleshoots unusual malfunctioning of aircraft. Coordinates all maintenance operations to expedite restoring aircraft to serviceable condition. Supervises maintenance of shop records, airplane and engine maintenance forms, and requisition and care of tools, equipment, parts and supplies.
 Must have a thorough working knowledge of all assemblies, systems, and AAF Technical Orders.
 Considerable experience in the inspection and maintenance of aircraft is required. Completion of a course in aircraft maintenance at an Army school is desirable.

Just my guesses working with the info we have so far :

1st: Reference to Training Detachment, AAFTTC, Ypsilanti, indicates he was assigned for training to Ford's Willow Run assembly plant, where B-24's were built. Lots of guys were assigned for training in the assembly plants for hands-on experience with the planes while they were still in little pieces before being put together. LOTS of info online about Willow Run, plus a member or two involved with the museum there now.  Steven ( WillowRun boardname ) comes to mind. He may have more info on the training detachment there.

2nd :  Amarillo Field Tx assignment MAY  tie in with his being a " Flight Engineer Instructor " ...... This field was mostly a training base for B-17 crews and mechanics, but later in the war, training for B-29 technicians was added to the training.
 Some of the larger planes, especially the B-29, required extensive training for Flight Engineers :

MOS 737     Flight Engineer

 Operates the engine control panel on very heavy multi-engine airplanes.
 At the pilot's direction adjusts throttles, mixture, supercharger and propeller pitch control to obtain varying conditions of engine speed, manifold pressure and fuel consumption. Performs such items of maintenence and adjustments as are possible during flight, such as correcting malfunctions of engines, cabin supercharger systems, landing gear, etc.  Maintains the weight and balance of the airplane during flight within allowable limits. Advises pilot as to computations of cruising range and data relating to fuel consumption. Advises pilot as to engine performance; weight and balances; and airworthiness of the airplane. Maintains a flight log and other necessary records during flight.
 Assists the ground crew chief with the daily and preflight inspections and reports to the pilot any deficiencies in the inspection and maintenance of the airplane. Directs loading of airplane.
 Must be physically qualified for flight duty, must have completed flight engineers course. Must be capable of rapid arithmetical computations. Should have previous exeperience as crew chief or similar responsible duty on two or four engine aircraft.


The Instructor would train the students to perform these duties.  My guess would be that he gained enough experience as a crew chief/ flight chief ( MOS 750 above )  that he was assigned as an Instructor at Amarillo AAF, although he would have gone through the flight engineer course, and would have had that MOS ?   May be that the paperwork to change MOS never caught up with him ?

The bars .... Mechanics bar would be pretty general, including airframe, engine, etc, while the Powerplant bar is specialized, so I would think the more specialized bar would be worn.

The museum's website is down for the time being  :(  A switch to new equipment destroyed the contrast and color of the pages, pics, etc which were made up on an old computer, and made them virtually unviewable. I am slowly trying to fix each page and picture, but its a slow process.