348 CONGRESSIONAL
INVESTIGATION PEARL HARBOR ATTACK
[556b] C-A16‑3/A4‑3(5)
/ND14(0348)
BASE DEFENSE AIR FORCE,
PATROL WING
TWO,
FLEET AIR DEPARTMENT,
NAVAL AIR STATION,
PEARL HARBOR, T. H., April 9, 1941.
(Confidential)
Annex Baker to
Commander Naval Base Defense Force Operation Plan‑No. 1‑41 dated
February 27, 1941.
NAVAL BASE DEFENSE AIR FORCE
OPERATION PLAN No. A‑1‑41
TASK ORGANIZATION
(a) Search and Attack Group (Commander Naval Base
Defense Air Force (Commander Patrol Wing Two))
The following units in accordance with current
conditions of readiness:
Patrol Squadrons.
Shore‑based VO‑VS
units.
Shore‑based carrier VB
and VT squadrons.
Shore‑based carrier VS
planes not assigned to the air combat group.
Shore‑based Marine VS
and VB squadrons.
Army bombardment squadrons.
Army reconnaissance
squadrons.
Navy Utility squadrons.
(b) Air Combat
Group (Senior VF Squadron Commander)
The following units in accordance with current
conditions of readiness:
Shore‑based carrier VF
squadrons.
Shore‑based Marine VF
squadrons.
One division of shore‑based
carrier type VS planes.
1. Information
This plan is made in
accordance with: The Joint Air Operations agreement approved and promulgated on
21 March 1941; Joint Estimate covering joint Army and Navy air action, addendum
I to this plan; and Pacific fleet confidential letter No. 2CL‑41 dated 15
February 1941. An air combat group under the direc [556c] tion of the Commander Hawaiian Air
Force will: Intercept and destroy hostile aircraft; Identify and report type of
attacking aircraft; Trail attacking carrier type planes to carrier and report
location to commander search and attack group; and as a secondary mission
support search and attack group upon request.
Assumptions: As in Addendum
I of this plan. Anti‑aircraft gun control in the Pearl Harbor area will
be coordinated with operations under this plan. Air traffic lanes and
recognition signals will be prescribed as found necessary.
2. This force will locate
and destroy hostile forces raiding against Oahu or Fleet units in the operating
areas.
PROCEEDINGS OF ROBERTS
COMMISSION 349
3. (a) Search and Attack
Group. (a) Locate, report, and track all hostile surface units in position to
take or threaten hostile action. Destroy hostile ships by air attack.
Priority of targets; (1) carriers (2) large supporting ships. if choice of
location is presented priority should be given to: (1) carrier involved in
attack (2) vessels beyond reach of our surface vessel interception.
(b) Air Combat Group. (b)
Operate as directed by the Commanding General Hawaiian Air Force.
(x) This plan is effective
upon receipt. It is operative without signal in the event of a surprise attack
on Oahu. It might be made operative by despatch. In the meanwhile conditions of
readiness prescribed in Addendum II will be taken as directed by the Commanding
General Hawaiian Department for Army units and by the Naval Base Defense
Officer (Commandant Fourteenth Naval District) for Navy units. This plan
supersedes and replaces Annex Baker of Naval Base Defense Force Operation Plan
No. 1‑41 of 27 February 1941. Units assigned to task groups of this plan
shall make readiness reports in accordance with Addendum II of this plan.
[556d] 4. The senior carrier commander based ashore at Fleet
Air Detachment, Pearl Harbor, shall at all times see that one division of VS
planes is detailed to the Air Combat Group. When all carrier planes gyre to
embark the Group Commander shall so inform the Commander Second Marine Aircraft
Group who will make the detail required by this paragraph.
5. Communications in
accordance with Annex Easy to Naval Base Defense Force Operation Plan No. 1‑40
of 27 February 1941. Use zone plus ten and one half time. Operation orders for
the search and attack group will be separately distributed.
Addendum I‑Joint
Estimate.
Addendum II‑Aircraft
Readiness.
P. N. L. BELLINGER,
Rear Admiral, U. S. Navy,
Commander
Naval Base Defense Air Force,
(Commander Patrol Wing Two).
Approved:
C. C. BLOCH,
Rear Admiral, U. S. Nary,
Commander Naval Base Defense Force.
Authenticated:
J. W. BAYS,
Lieutenant, U. S. Navy.
C‑A16‑3/A4‑3(5)/ND14(0348) MARCH
31, 1941.
(Confidential)
Commander
Naval Base Defense Air Force, Commander Patrol Wing Two, Naval Air Station,
Pearl Harbor, T. H.
Commanding General, Hawaiian Air Force, Fort
Shafter, T. H.
Addendum I to Naval Base Defense Air Force Operation
Plan No. A‑1‑41.
Joint estimate covering
Joint Army and Navy air action in the event of sudden hostile action, against
Oahu or Fleet Units in the Hawaiian area.
I. Summary of
the Situation.
(a) Relations between the
United States and Orange are strained, uncertain, and varying.
[556‑e] (b) In the past Orange has
never preceded hostile actions by a declaration of war.
(c) A successful, sudden
raid, against our ships and Naval installations on Oahu might prevent effective
offensive action by our forces in the Western Pacific for a long period.
(d) A strong part of our
fleet is now constantly at sea in the operating areas organized to take prompt
offensive action against any surface or submarine force which initiates hostile
action.
(e) It appears possible that
Orange submarines and/or an Orange fast raiding force might arrive in Hawaiian
waters with no prior warning from our intelligence service.
350 CONGRESSIONAL
INVESTIGATION PEARL HARBOR ATTACK
II. Survey of
Opposing Strengths.
(a) Orange might send into
this area one or more submarines and/or one or more fast raiding forces
composed of carriers supported by fast cruisers. For such action she is known
to have eight carriers, seven of which are reported to be capable of 25 knots
or over and four of which are rated at 30 knots or better. Two of the carriers
are converted capital ships, armored and armed with 10‑8" guns each
and reported to have heavy AA batteries. Two others are small (7000 treaty
tons) and limited to 25 knots. Exact information on numbers; and
characteristics of the aircraft carried by these ships is not available.
However the best estimate at present available is that the small carriers can
accommodate from 20 to 30 planes and the large ones about 60. Probably the best
assumption is that carrier complements are normally about equally divided
between fighter and bomber types. Lacking any information as to range and
armament of planes we must assume that they are at least the equal of our
similar types. There probably exist at least 12 eight inch gun and at least 12
six inch gun fast modern cruisers which would be suitable supports. Jane's
Fighting Ships (1939) shows over forty submarines which are easily capable of
projection into this area. An Orange surface raiding force would be far removed
from their base and would almost surely be inferior in gun power to our surface
forces operating at sea in the Hawaiian area.
(b) The most difficult situation for us to meet would be when
several of the above elements were present and closely coordinated their
actions. The shore based air force available to us is a constantly varying
quantity which is being periodically augmented by reinforcements from the
mainland and which also varies as fleet units are shifted. Under existing
conditions about one‑half of the planes present can be maintained in a
condition of material readiness for flight.
The aircraft at present available in Hawaii are inadequate to maintain,
for any extended period, from bases on Oahu, a patrol extensive enough to
insure that an air attack from an Orange carrier cannot arrive over Oahu as a
complete surprise. The projected outlying bases are not yet in condition to
support sustained operations. Patrol planes are of particular value for long
range scouting at sea and are the type now available in this area best suited
for this work. If present planes are used to bomb well defended ship
objectives, the number available for future use will probably be seriously
depleted. In view of the continuing need for long range overseas scouting in
this area the missions of those planes for operations as contemplated in this
estimate should be scouting. Certain aircraft of the Utility Wing, although not
designed for combatant work, can be [556‑g] used to advantage in augmenting the scouting of patrol planes.
Other types of aircraft, in general, can perform functions that accord with
their type.
III. Possible
Enemy Action.
(a) A declaration of war might
be preceded by.
1. A surprise
submarine attack on ships the operating area.
2. A surprise
attack on Oahu including ships and installations in Pearl Harbor.
3. A
combination of these two.
(b) It appears that the most
likely and dangerous form of attack on Oahu would be an air attack. It is
believed that at present such an attack would most likely be launched from one
or more carriers which would probably approach inside of three hundred miles.
(c) A single attack might or
might not indicate the presence of more submarines or more planes awaiting to
attack after defending aircraft have been drawn away by the original thrust.
(d) Any single submarine
attack might indicate the presence of a considerable undiscovered surface force
probably composed of fast ships accompanied by a carrier.
(e) In a dawn air attack
there is a high probability that it could be delivered as a complete surprise
in spite of any patrols we might be using and that it might find us in a
condition of readiness under which pursuit would be slow to start, also it
might be successful as a diversion to draw attention away from a second
attacking force. The major disadvantage would be that we could have all day to
find and attack the carrier. A dusk attack would have the advantage that the carrier
could use the night for escape and might not be located the [556‑h] next day near enough for us to make
a successful air attack. The
PROCEEDINGS OF ROBERTS COMMISSION 351
disadvantage would be that it would spend the day of the attack approaching the islands and might be
observed. Under the existing conditions this might not be a serious
disadvantage for until an overt act has been committed we probably will take no
offensive action and the only thing that would be most would be complete surprise.
Midday attacks have all the disadvantages and none of the advantages of the
above. After hostilities have commenced, a night attack would offer certain
advantages but as an initial crippling blow a dawn or dusk attack would
probably be no more hazardous and would have a better chance for accomplishing
a large success. Submarine attacks could be coordinated with any air attack.
IV. Action
open to us:
(a) Run daily patrols as far
as possible to seaward through 360 degrees to reduce the probabilities of
surface or air surprise. This would be desirable but can only be effectively
maintained with present personnel and material for a very short period and as a
practicable measure cannot, therefore, be undertaken unless other intelligence
indicates that a surface raid is probable within rather narrow time limits.
(b) In the, event of any
form of surprise attack either on ships in the operating areas or on the
islands
1. Immediate
search of all sea areas within reach to determine the location of hostile surface
craft and whether or not more than one
group is present.
2. Immediate
arming and preparation of the maximum possible bombing force and its despatch
for attack when information is available.
[556i] (c)
In the event of an air attack on Oahu, in addition to (b) above:
1. The
immediate despatch of all aircraft suitable for aerial combat to intercept the
attackers.
2. The prompt
identification of the attackers as either carrier or long range shore based
aircraft.
3. The prompt
dispatch of fast aircraft to follow carrier type raiders back to their carrier.
(d) In event of a submarine
attack on ships in the operating area in addition to (b) above:
1. Hold pursuit
and fighter aircraft in condition of immediate readiness to counter a possible
air raid until search proves that none is imminent.
2. Dispatch
armed shore based fleet aircraft to relieve planes in the air over the attack
area.
3. Establish a
station patrol by patrol planes two hundred twenty mile radius from scene of
attack at one hour before daylight of nest succeeding daylight period.
(4) None of the above
actions can be initiated by our forces until an attack is known to be imminent
or has occurred. On the other hand, when an attack develops time will probably
be vital and our actions must start with a minimum of delay. It therefore
appears that task forces should be organized now, missions assigned, conditions
of readiness defined and detailed plans prepared so that coordinated immediate
action can be taken promptly by all elements when one of the visualized
emergencies arises. To provide most effectively for the necessary immediate
action, the following joint task units will be required.
1. Search Unit.
2. Attack Unit.
3. Air Combat Unit.
[556j] Carrier scouts, army reconnaissance
and patrol planes can be employed with very widely varying effectiveness,
either for search or attack. Under varying conditions some shifts of units
between the search and attack groups may be desirable. Also, the accomplishment
of these two tasks must be closely coordinated and therefore these two groups
should be controlled by the same task group commander.
V. Decisions:
1. This force will locate
and attack forces initiating hostile actions against Oahu or fleet units in
order to prevent or minimize damage to our forces from a surprise attack and to
obtain information upon which to base coordinated retaliatory measures.
352 CONGRESSIONAL
INVESTIGATION PEARL HARBOR ATTACK
2. Subsidiary decisions. In
order to be in all respects prepared to promptly execute the above decision.
(a) Establish a task
organization as follows by the issue of a joint air operation plan:
1. Search and Attack Group
(Commander Naval Base Defense Air Force (Commander Patrol Wing Two))
The following units in
accordance with current conditions of readiness:
Patrol
squadrons.
Shore‑based
VO‑VS units.
Shore‑based
carrier VB and VT squadrons.
Shore‑based
carrier VS planes not assigned to the air combat group.
Shore‑based
Marine VS and VB squadrons.
Army
bombardment squadrons.
Army
reconnaissance squadrons.
Navy Utility
squadrons.
[556k] 2. Air Combat Group (Commander Hawaiian Air
Force) The following units in accordance with current conditions of readiness:
Army pursuit
squadrons.
Shore‑based
carrier VF squadrons.
Shore‑based
Marine VF squadrons.
One division of
shore‑based carrier VS planes.
(Primarily for trailing
aircraft)
(b) Assign missions to the
above groups as follows:
1. Search and Attack Group.
Locate, report and track all hostile surface units in position to take or
threaten hostile action. Destroy hostile ships by air attack. Priority of
targets: (1) carriers (2) large supporting ships. If choice of location is
presented priority should be given to: (1) carrier involved in attack (2)
vessels beyond teach of surface vessel interception.
2. Air Combat Group.
Intercept and destroy hostile aircraft. Identify and report type of attacking
aircraft. Trail attacking carrier type planes to carrier and report location to
commander search and attack group. As a secondary mission support search and
attack group upon request.
(c) Provide a means for
quickly starting all required action under this plan when
(a) An air
attack occurs on Oahu.
(b) Information
is received from any source that indicates an attack is probable.
(c) Information
is received that an attack has been made on fleet units.
(d) Define conditions of
readiness for use with this plan as follows:
[556‑l]
Conditions of readiness shall be prescribed by a combination of a letter and
number from the tables below. The letter indicating the part of a unit in a
condition of material readiness for its assigned task and the number indicating
the degree of readiness prescribed for that part.
Material Readiness:
A. All assigned operating
aircraft available and ready for a task.
B. One‑half of all
aircraft of each functional type available and ready for a task.
C. Approximately one‑quarter
of all aircraft of each functional type available and ready for a task.
D. Approximately one‑eighth
of all aircraft of each functional type available and ready for a task.
E. All aircraft conducting
routine operations, none ready for the purposes of this plan.
Degree of Readiness:
1. For pursuit and VF
types—four minutes. Types other than fighters—fifteen minutes:
2. All types—30 minutes.
3. All types—one hour.
4. All types—two hours.
5. All types—four hours.
The armament and fuel load
for each type under the above conditions of readiness are dependent upon the
tasks assigned in contributory plans and orders and will be prescribed therein.
(e) Establish a procedure
whereby the conditions of readiness to be maintained by each unit is at all
times prescribed by the Senior Officers Present of
PROCEEDINGS OF ROBERTS COMMISSION 353
the Army and Navy as a result of all information
currently [556‑m] available to them. In using the above conditions
it should be noted that: Condition A‑1 requires a preparation period of
reduced operations and can be maintained for only a short time as it is an all
hands condition. Conditions B‑1 and B‑2 require watch and watch for
all personnel and personnel fitness for air action will decrease rapidly if
they are maintained too long. Any Condition 1, 2, or 3 will curtail essential
expansion training work. Conditions C, or D, 4 or 5 can be maintained without
unduly curtailing normal training work.
(f) In order to perfect
fundamental communications by use and to insure that prospective Task Group
Commanders at all times know the forces immediately available to them for use,
under the plan above, in case of a sudden emergency, provide, for daily
dispatch readiness reports as of the end of normal daily flying from all units
to their prospective task force commander. These reports to state:
(a) Number of
planes in the unit by functional types such as bomber, fighter, etc.
(b) Number of
each type in commission for flight and their degree of readiness as defined
above.
(g) After the joint air
operations plan under subsidiary decision (a) above has been issued, the task
group commanders designated therein will prepare detailed contributory plans
for their groups to cover the various probable situations requiring quick
action in order that the desired immediate action in an emergency can be
initiated with no further written orders. To assist in this work the following
temporary details will be made:
(a) By
Commander Naval Base Defense Air Force (Commander Patrol Wing Two): an officer
experienced in [556‑n] VF and VS operations and planning to
assist the Commander of Air Combat Group.
(b) By the
Commander Hawaiian Air Force: an officer experienced in Army bombardment and
reconnaissance operations and planning to assist the Commander of the Search
and Attack Group.
F. L. MARTIN,
Major General, U. S. Army,
Commanding
Hawaiian Air Force.
P. N. L. BELLINGER,
Rear Admiral, U. S. Navy,
Commander Naval Base Defense Air Force,
(Commander Patrol Wing Two).
Authenticated:
J. W. BAYS,
Lieutenant, U. S. Navy.
C‑A16‑3/A4‑3(5)/ND14 (0348)
(Confidential)
BASE DEFENSE AIR FORCE,
PATROL WING TWO,
FLEET AIR DETACHMENT,
NAVAL AIR STATION,
Pearl Harbor, T. H., April 9, 1941.
Addendum II to Naval Base Defense Air Force
Operation Plan No. A‑1‑41.
Conditions of readiness and
readiness reports:
1. Conditions of readiness
will be prescribed by a combination of a letter and a number from the tables
below. The letter indicating the part of a unit in a condition of material
readiness for its assigned task and the number indicating the degree of
operational readiness prescribed for that part.
Material Readiness
A. All assigned operating
aircraft available and ready for a task.
B. One‑half of all
aircraft of each functional type available and ready for a task.
C. Approximately one‑quarter
of all aircraft of each functional type available and ready for a task.
[556‑o] D. Approximately one‑eighth of all
aircraft of each functional type available and ready for a task.
E. All aircraft conducting
routine operations, none ready for the purposes of this plan.
Degree of operational
readiness:
354 CONGRESSIONAL
INVESTIGATION PEARL HARBOR ATTACK
All times listed in this
table are the maximums allowed for the first plane of a unit to be in the air
armed and proceeding with the assigned task.
1. For pursuit
and VF types—four minutes. Types other than fighters—fifteen minutes.
2. All types—30
minutes.
3. All
types—one hour.
4. All
types—two hours.
5. All
types—four hours.
2. The armament and fuel
load for each type under the above conditions of readiness are dependent upon
the task assigned in contributory plans and orders and will be prescribed in
these.
3. Readiness Reports
(a) A despatch readiness
report, as of 1500 each day shall be made by each unit assigned to a task group
by this plan as follows:
(1) Units of "Search
and Attack Group" to the Commander Naval Base Defense Air Force (Commander
Patrol Wing Two).
(2) Units of the "Air
Combat Group" to the Commanding General of the Hawaiian Air Force via
Commander Naval Base Defense Air Force.
(b) These reports shall
state:
(1) The number
of operating planes in the unit by functional types as bomber, fighter, etc.
(2) The number
of each type in material readiness [556p] for flight and their degree of
operational readiness as defined above.
(c) The officer detailing VS
planes to the Air Combat Unit (paragraph 4 of N. B. D. A. F. plan No. A‑1‑41)
shall inform the Commander Naval Base Defense Air Force and Commander General
Hawaiian Air Force by despatch of the detail and any changes therein.
(PROCEEDINGS OF THE ROBERTS
COMMISSION.)