HEADQUARTERS                                          HEADQUARTERS
14th Naval DISTRICT                                   HAWAIIAN DEPARTMENT
PEARL HARBOR, T. H.                                   FORT SHAFTER, T. H.
 
JOINT COASTAL FRONTIER DEFENSE PLAN, HAWAIIAN DEPARTMENT AND FOURTEENTH
                        NAVAL DISTRICT, 1939
 
                                                           28 MARCH 1941.
 
         ANNEX NO. VII        SECTION VI         JOINT AGREEMENTS
 
    JOINT SECURITY MEASURES, PROTECTION OF FLEET AND PEARL HARBOR BASE
 

1. General

1. In order to coordinate Joint defensive measures for the security of the fleet and for the Pearl Harbor Naval Base for defense against hostile raids or air attacks delivered prior to a declaration of war and before a general mobilization for war, the following agreements, supplementary to the provisions of the HCF-39, (14 ND-JCD-13), are adopted. These agreements are to take effect at once and will remain effective until notice in writing by either party of their renouncement in whole or in part. Frequent revision of these agreements to incorporate lessons determined from joint exercises will probably be both desirable and necessary.

II. Joint Air Operations

2. When the Commanding General of the Hawaiian Department and the Naval Base Defense Officer, (the Commandant of the 14th Naval District), agree that the threat of a hostile raid or attack is sufficiently imminent to warrant such action, each commander will take such preliminary steps as are necessary to make available without delay to the other commander such proportion of the air forces at his disposal as the circumstances warrant in order that joint operations may be conducted in accordance with the following plans:

a. Joint air attacks upon hostile surface vessels will be executed under the tactical command of the Navy. The Department Commander will determine the Army bombardment strength to participate in each mission. With due consideration to the tactical situation existing, the number of bombardment airplanes released to Navy control will be the maximum practicable. This force will remain available to the Navy, for repeated attacks, if required, until completion of the mission, when it will revert to Army control.

b, Defensive air operations over and in the immediate vicinity of Oahu will be executed under the tactical command of the Army. The Naval Base Defense Officer will determine the Navy fighter strength to participate in these missions. With due consideration to the tactical situation existing, the number of fighter aircraft released to Army control will be the maximum practicable. This force will remain available to the Army for repeated patrols or combat or for maintenance of the required alert status until, due to a change in the tactical situation, it is withdrawn by the Naval Base Defense Officer (Commandant, 14th Naval District), and reverts to Navy control.

c. When naval forces are insufficient for long distance patrol and search operations, and Army aircraft are made available, these aircraft will be under the tactical control of the naval commander directing the search operations.

d. In the special instance in which Army pursuit protection is requested for the protection of friendly surface ships, the force assigned for this mission will pass to the tactical control of the Navy until completion of the mission.

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III. Joint Communications

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5. Pending the establishment of the Aircraft Warning Service, The Army will operate an Antiaircraft Intelligence Service which, using wire and radio broadcasts, will disseminate information pertaining to the movements of friendly and hostile aircraft. It should be understood that the limitations of the AAAIS are such that the interval between receipt of a warning and the air attack will in most cases be very short. Radio broadcasts from the AAAIS will be transmitted on 900 kilocycles. All information of the presence or movements of hostile aircraft off-shore from Oahu which is secured through Navy channels will be transmitted promptly to the Command Post of the Provisional Antiaircraft Brigade.

6. Upon establishment of the Aircraft Warning Service, provision will be made for transmission of information on the location of distant hostile and friendly aircraft. Special wire or radio circuits will be made available for the use of Navy liaison officers, so that they may make their own evaluation of available information and transmit them to their respective organizations. Information relating to the presence or movements of hostile aircraft offshore from Oahu which is secured through Navy channels will be transmitted without delay to the Aircraft Warning Service Information Center.

7. The several joint communications systems listed in paragraphs 3 and 4 above, the Antiaircraft intelligence Service, and the Aircraft Warning Service (after establishment) will be manned and operated during combat, alert periods Joint exercises which involve these communications systems and at such other periods as may be agreed upon by the Commanding General Hawaiian Department and the Naval Base Defense Officer. The temporary loan of surplus communication equipment by one service to the other service to fill shortages in joint communication nets is encouraged where practicable. Prompt steps will be taken by the service receiving the borrowed equipment to obtain replacements for the borrowed articles through their own supply channels.

IV. Joint Antiaircraft Measures

8. Arrival and Departure Procedure, Aircraft.

During Joint exercises, alert periods and combat, and at such other times as the Commanding General Hawaiian Department and the Naval Base Defense Officer (Commandant Fourteenth Naval District) may agree upon, all Army and Navy aircraft approaching Oahu or leaving airfields or air bases thereon will conform to the Arrival and Departure Procedure prescribed in Inclosure A. This procedure will not be modified except when a departure therefrom is essential due to combat (real or simulated during exercises) or due to an emergency.

9. Balloon barrages.

Reports from abroad indicate the successful development and use of balloon barrages by European belligerents both British and German. Although detailed information is not available, the possibilities of balloon barrages in the Oahu area are recognized. Further investigation and study is necessary both locally and by the War and Navy Departments in order to determine the practicability of this phase of local defense.

10. Marine Corps Antiaircraft Artillery.

When made available by the Naval Base Defense Officer, (Commandant, 14th Naval District), Marine Corps units manning antiaircraft artillery present on Oahu will be placed under the tactical control of the Commanding General, Hawaiian Separate Coast Artillery Brigade.

11. Aircraft Warning Service.

The Army will expedite the installation and placing in operation of an Aircraft Warning Service. During the period prior to the completion of the AWS installations, the Navy, through use of RADAR and other appropriate means, will endeavor to give such warning of hostile attacks as may be practicable.

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                                         (Signed) Walter C. Short,
                                                  WALTER C. SHORT,
                                          Lieutenant General U. S. Army,
                                         Commanding, Hawaiian Department.
 
Approved: 2 April 1941.
   (Signed) C. C. Bloch
            C. C. BLOCH,
   Rear Admiral, U. S. Navy,
Commandant Fourteenth Naval District.