OFFICE OF CHIEF OF NAVAL OPERATIONS
29 May 1944
INSTRUCTIONS FOR THE USE OF AIRCRAFT CODE NO. 16
1. CSP 1272(A),"Instructions for the Use of Aircraft Code No. 16", will become effective when so directed by the Chief of Naval Operations. It is to be used in conjunction with Aircraft Code No. 16 (CSP 1270 series).
2. This is a CONFIDENTIAL non-registered publication and shall be handled, stowed and transported in accordance with the effective edition of the Registered Publication Manual (RPS 4). It is distributed in accordance with the Allowance Tables in Chapter 1 of the effective edition of RPS 6.
3. This publication may be carried in aircraft for use therein.
4. IT IS FORBIDDEN TO MAKE EXTRACTS FROM OR TO COPY THIS PUBLICATION WITHOUT SPECIFIC AUTHORITY FROM THE CHIEF OF NAVAL OPERATIONS EXCEPT AS PROVIDED FOR IN THE CURRENT EDITION OF THE REGISTERED PUBLICATION MANUAL.
THIS PUBLICATION CONSISTS OF EIGHT (8) PAGES.
(Printed - June 1944)
INSTRUCTIONS FOR THE USE OF AIRCRAFT CODE NO. 16 (CSP 1270 Series)
Aircraft Code No. 16 (CSP 1270 Series) is intended for use by:
(b) Other forces or units for
(1) Communicating with aircraft.
(2) Encrypting contact or amplifying reports.
(3) Encrypting urgent tactical messages when no other suitable system is held.
The primary purpose of this code is for aircraft communications and contact reports. It shall not be used for general purposes by shore or surface units when other suitable rapid systems are available.
2. SETS OF EDITIONS
Six editions of the aircraft code are packaged together, each bearing the same edition letters and register number, but further identified by an edition number; for example, CSP 1270 (DA1), (DA2), (DA3), (DA4), (DA5) and (DA6). Each package of six editions is known as a "set". Effective and ROB dates are shown in status CSPMs.
3. EMERGENCY SUPERSESSION
To permit emergency supersessions due to compromise without disturbing the schedule of normal supersessions, a series of emergency editions are employed. These are known as "X" editions, and bear the short title CSP 1270(XA1)-(XA6), (XB1)-(XB6), etc. Whenever an edition of the regular series is compromised under conditions which make replacement possible and necessary, an "X" edition is introduced to remain effective until the next scheduled change. Thus an emergency supersession does not affect subsequent scheduled dates of effectiveness of the regular series.
4. METHOD OF ISSUE AND ACCOUNTING
The six numbered editions for one month are to be issued by RPIO's and transferred between "holders" only in one package (a set).
All six editions in a set, each bearing the same register number, shall be accounted for as one publication. Destruction of the set shall be reported on form RPS 2 five days after supersession of the sixth edition.
Although the "X" editions are also issued in sets of six (e.g. CSP 1270 XA1-XA6), some months may elapse before the sixth edition has been used, since these have no regular schedule of effectiveness but are used only for emergency supersessions. The accounting procedure is the same as for regular editions, and destruction of the entire set shall be reported after the last edition of the set has been destroyed.
Prompt report must be made of loss or compromise of any single numbered edition. Such reports will refer, for example to CSP 1270(DF3), Reg. No. 1569, etc.
Single editions may be issued to users such as aircraft on local custody, or in "in transit holder" status when appropriate. In the event such users become casualties or do not return to place of issue, destruction reports for the "sets" shall contain a notation as to the disposition of such single editions.
Holders, other than those to whom originally issued, having single editions turned in by aircraft or others, shall give a local receipt for such editions; destroy them promptly (regardless of supersession date), and report destruction on separate form RPS 2 to the Registered Publication Section. If the last holder of record was not an "in transit holder," RPS will notify him upon receipt of such destruction report.
5. GENERAL CONSTRUCTION
The aircraft code is a two-part code (that is, having separate sections for encoding and decoding), containing the following sections (listed in the order in which they appear):
The special Weather Report normally consists of eight digits representing the seven weather elements indicated at the top of the columns on page 2 of the code. Each report must include all the elements and must contain at least eight digits, since otherwise proper interpretation of the report is impossible. (When reporting wind force greater than 9, the report will contain ten digits). If any element is unknown it must be estimated, unless the element includes the entry "undetermined". A weather report will first be encoded in the weather report code on page 2 of the code. The eight digits thus obtained must then be encoded by pairs of digits. Weather reports may be sent separately or appended to the text of a despatch but in either case the weather report must be prefixed by one of the groups meaning "Weather Report follows".
7. NUMERAL TABLE
A numeral table will be found on pages 2 and 3 of the code. In forming numbers which are not found in the table, combinations will be used. Thus 4750 may be formed by using the code groups for 47 and 50; and 690 may be formed by using either the code groups for 69 and 0, or the code groups for 6 and 90. If two separate numbers, such as 4750 and 690, appear in succession in a message, they must be separated by using the code group for "space".
Thus 4750 690 is encoded as:
(These code groups are only examples and do not represent genuine code groups).
(a) The vocabulary is designed for tactical communications involving aircraft. Plain language or Q-signals shall never be mixed with code groups In the text of a message. Basic words
in the vocabulary should be understood as singular or plural, noun, adjective, verb or adverb, depending upon their context. Common word endings follow the basic words. These word endings may be used or disregarded according to the context.
(b) If the context is such that ambiguity may result, an appropriate ending to a basic word may be supplied from the Syllabary.
(c) Where expressions contain words enclosed in parentheses, the enclosed words may be understood as applicable or may be ignored, as the context warrants. Where blanks not enclosed in parentheses appear in a phrase (as for example: "Illuminate __ with flares"), these blanks must be filled in with the appropriate word(s) or number (s), encoded as the next group(s).
(d) Basic words are arranged in strict alphabetical order, and all sequences or words and sentences will be found in the alphabetical order of the first word.
(e) Designations of U.S. ships may be encoded in two groups by using their type and number. Thus "IOWA" would be encoded by using the code groups for "BB (No. __)" and "61" as found in the vocabulary and numeral table respectively. Abbreviations for all the most common ship types will be found in the vocabulary.
9. AIRCRAFT HOMING CODE
(a) The Aircraft Homing Code contains code letters for use as bearing signals on YE, YG and YG-1 homing equipment installed on board ship. It is not to be used on shore-based equipment. The key list designates the arrangement of bearing signal cams on the bearing signal cam disk. The course toward "home" to be steered by the aircraft is the reciprocal of the bearing indicated.
(b) A sample Homing Code, as appearing in CSP 1270 series, is reproduced below.
Using the above keys, the signal D indicates that the course toward "home" is 240°; U indicates a course toward "home" of 120°.
The Syllabary contains groups for single letters, common letter combinations and syllables. These may be used to build up words not appearing in the vocabulary, either by themselves or in conjunction with words already in the vocabulary.
11. GEOGRAPHICAL LIST
The Geographical List is a listing of important locations, arranged in alphabetical order. Grouped at the beginning of the list are such terms as "bay", "cape", "channel", etc., which may be used in conjunction with place-names in the geographical list. Thus "Singapore Strait" may be formed by using the code group for "Singapore" and the code group for "Strait".
12. SPARE GROUPS
A list of 35-spare groups is provided, shown as "Spare 1," "Spare 2," etc. These may be assigned locally. When so assigned, spare groups shall not be used in transmissions to forces outside of the area of local assignment.
13. CONTACT REPORT SECTION
(a) Contact reports may be made
(1) By abbreviated plain language (see USF 70(A));
(2) By the Contact Report Section of the Aircraft Code.
In sending plain-language contacts, the Contact Report Section will serve as a convenient check-off list to assure that all necessary information is supplied.
(b) In sending contacts by the Contact Report Section, select (check off or write down) the code group or groups from the various columns, in order, which best describe the situation. Attention is invited to the fact that current Fleet doctrine requires that an initial contact report contain data from columns 2 - 5 inclusive. Data from columns 1, 6, and 7 is not required but may be included in an initial report or subsequent amplifying reports.
(c) In encoding Latitude, Longitude, Bearing, Distance and Course by the Contact Report Section, it will sometimes be necessary to combine numbers. Thus in sending Lat. 89° 45' the encoder will use code groups for the following meanings:
(from the "Tens" column under "Latitude Degrees")
(from the "Units" column under "Latitude Degrees")
(from the "Tens" column under "Latitude Minutes")
(from the "Units" column under "Latitude Minutes")
For "Bearing 260°" code groups for the following would be sent:
Similarly for "Distance 45" code groups for the following would be sent:
(d) A column for Japanese merchant ship types is included in the Contact Report Section, in which types are identified by such abbreviations as "Fox Able," "Fox Tare Baker", "Tare Able Two Stacks", etc. These abbreviations are taken from "J.M.S.T." (Japanese Merchant Shipping Tonnage), prepared by the Allied Air Forces, Southwest Pacific Area. Code groups for these abbreviations in the aircraft code are not to be used unless "J.M.S.T." is in concurrent use in the area concerned.
(e) The example below illustrates the encoded version of the following contact (the code groups are only examples and do not represent genuine code groups from any publication):
Two carriers, six light cruisers, eight destroyers bearing 120 degrees,
distance 30 miles from Point Baker, course 250 degrees, speed 20 knots
Col. 2 and 3
Distance 30 (Miles)
REF. PT. B
Method of transmission (address, repetitions, "F" or "R" method, etc.) shall be as prescribed by Fleet doctrine and/or instructions from the OTC.
14. DECODE SECTION
The Decode Section contains meanings for all of the four-letter code groups in the aircraft code. Meanings for numeral groups in decoded weather reports may be found in the table on page 2.
15. GARBLE TABLE
The garble table used in constructing code groups for a particular edition of the aircraft
code appears on the back cover of that edition. An explanation of the method of using garble tables to clear garbled groups or to identify the edition from which code groups have been taken is contained in the effective edition of CSP 1467.
(a) The Authenticator on the cover of the aircraft code is for use only in communication to and from aircraft and minor surface craft. Authentication may take two forms: (1) challenge and reply; (2) message (or direct) authentication.
(b) Challenge and Reply. (Refer to sample Authenticator Table on page 8).
The authenticator consists of a challenge of three letters and a reply of one letter.
The three letters of the challenge are any three letters chosen at random.
The one-letter reply is determined as follows:
Assume as a challenge PZX. Locate in the left-hand vertical column of the table the first letter (P), proceed horizontally along the line designated by P to the second letter (Z), then vertically (up or down) in the column designated by Z to the third letter (X). Now proceed horizontally along this line to the letter in the right hand column (which in this example is V). V is
The challenger himself must of course go through this process to ascertain that the reply as received is correct.
In voice communications the challenge is spoken after the word "Authenticate".
"Hullo Able Baker this is Peter three, authenticate Peter Zebra Xray, over".
The reply is spoken after the phrase "Authenticator is".
"Hullo Peter three this is Able Baker, authenticator is Victor over".
In telegraphic communication the challenge is transmitted after the operating signal QPA meaning "Authentication challenge is___".
P3 V AB QPA PZX K
The reply is transmitted (sent twice) after the operating signal QKA meaning "Authentication of this message is__".
P3 V AB QKA VV K
(c) Message (Direct) Authentication. (Refer to sample Authenticator Table on page 8).
By this method a properly authenticated message may be sent without requiring any transmissions from the addressee. The authenticator consists of a single letter repeated. Elements used are: Hour of origin, as shown in the time group (or hour of transmission if a time group is not used); the last character of the originator's call; and the first letter of text.
Authentication is accomplished as follows:
(1) Select the letter in the left hand vertical column representing time in hours (as taken from the substitution table in the Authenticator).
(2) Proceed horizontally along the line designated by this letter to the last character of the originator's call sign (substitute from the substitution table if the last character is a digit).
(3) From the letter found in paragraph 2, above, proceed vertically to the first letter of text. (If the text consists entirely of numbers, use the first digit in the text, and substitute from the substitution table).
(4) The authenticator is the letter in the right hand vertical column horizontally opposite the letter located in paragraph 3 above. This letter is sent twice following the operating signal QKA meaning "Authentication for this message or transmission is __", in the final instructions of the message.
EXAMPLE: Time 1715 (17=Q)
C1M V 144Z BT XRAY YOKE MIKE - etc - BT QKA DD AR
SAMPLE AUTHENTICATOR TABLE
NUMERICAL SUBSTITUTION TABLE
From US NARA College Park, RG38, CNSG Crane Library Box 67