NATIONAL BUREAU OF STANDARDS REPORT

4669

Development, Testing, and Evaluation of Visual Landing Aids

Consolidated Progress Report F6r the Period January 1 to March 31, 1956

By

Photometry and Colorimetry Section

Optics and Metrology Division

<NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards is suggested in the following listing

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description of the activities, and of the resultant reports and publications, appears on the inside

of the back cover of this report.

Electricity and Electronics. Resistance and Reactance. Electron Tubes. Electrical Instru- ments. Magnetic Measurements. Process Technology. Engineering Electronics. Electronic

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Radio Standards. High Frequency Standards. Microwave Standards. • Office of Basic Instrumentation • Office of Weights and Measures
NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2301 May 1956 4669

0201-20-2304

0201-20-2327

Development Testing, and Evaluation of

Visual Landing Aids

Consolidated Progress Report

to the

Airborne Equipment Division

Bureau of Aeronautics

Department of the Navy

For the Period

January 1 to March 31 t 1956

for

Bureau of Aeronautics Projects

TED No. NBS-AE- 10002

TED No. NBS-AE- 10011

<^NBS>

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, reprinting, or reproduction of this report In any form, either in whole or in part, is prohibited

unless permission Is obtained in wrltingfrom t heOffice of theDirector, National Bureau of Standards, Washington

25, D, C. Such permission is not needed, however, by a Government agency for which a report has been specifically prepared if that agency wishes to reproduce additional copies of that particular report for its own use,

Development, Testing, and Evaluation of

Visual Landing Aids

January 1 to March 31, 1956

I. REPORTS ISSUED

BfiPQlXu flfi* liile

4533 Development, Testing, and Evaluation of Visual

Landing Aids, Consolidated Progress Report for

the Period October 1 to December 31, 1955*

4554 Computation of the Effective Intensity of

Flashing Lights. C. A, Douglas

4558 Theory of the Tra nsmis some ter Photometric

System. C. A. Douglas, A. N. Hill

21A-3/56 Operating Characteristics of Ballast Resistors

of Reduced Size.

21 P-1/56 Photometric Tests of Two Type 4545 PAR 56 Lamps

and Three Special 250-Watt PAR 56 Lamps.

21 P-3/56 Photometric Tests of Ttoo 300-Watt, 25-Volt and

Two 200-Watt, 6.6-Ampere PAR 56 Approach-Light

Lamps.

21 P-4/56 Photometric Test of Three 500-Watt, 20-Ampere

and Three 300-Watt, 20-Ampere PAR 56 Approach*^

Light Lamps.

II. RESEARCH AND DEVELOPMENT, LABORATORY TESTING, AND CONSULTATION

SERVICES IN CONNECTION WITH VISIBILITY, AIRFIELD LIGHTING, AM)

FOG MODIFICATION PROBLEMS (TED NBS-AE-10002)

a. Visibility Meters and Their Addli cation,

Transmi s some ter s. A second experimental phototube with an

S-4 surface has been received and checked. This tube is more

stable and has a lower dark current than the first tube of this
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type. However, neither the sensitivity nor the dark current are

as satisfactory as similar tubes with an S-l surface. Neither

surface has the desired spectral sensitivity. Efforts to obtain

tubes with a photosensitive surface having the desired spectral

sensitivity are continuing.

A report "Theory of the Transmis some ter Photometric System,”

has been completed and released. This report presents an

analysis of the theory of operation of the transmis some ter photometric system, a discussion of the sources of error in the photometric system and methods of minimizing the errors, and an

analysis of the effects of these errors upon the indicated

visibility. (NBS Report No. 4558)

b. A|rfjfii&.Ugbii.ng_flfld. Marking.

Approach-Light Lamps. Intensity distribution measurements

and intensity-current/voltage measurements have been made of

two 300-watt, 25-volt, and two 200-watt, 6.6-ampere, PAR 56

approach-light lamps manufactured by the Westinghouse Electric

Corporation, and of three 500-watt, 20-ampere and three 300-watt,

20-ampere, PAR 56 approach-light lamps manufactured by the

General Electric Company. The 500-watt lamp is intended for use

in the high-intensity seadrome lighting at NAS, Norfolk. All of

these lamps have beam patterns similar to those developed for the

350-vratt and 399-watt approach-light lamps. The ratio of the

intensities of the 500-watt and 300-watt, 20-ampere lamps is

slightly greater than the ratio of their power consumption, pre-

, sumably because the 500-watt lamps have a somewhat shorter life.

The results have been reported in NBS Test Reports 21P-3/56 and

21 P-4/56.

Constant-Current Regulator. A type C-l, 4-kilowatt, 6.6-

ampere constant-current regulator was received from Navy stock

and installed for use in tests of airfield lighting equipment.

The regulator was found to be defective and has been sent to

the manufacturer for repair.

Runway Distance Markers. The study of the intensity-current

characteristics of PAR 38 lamps when operated from 30/45- and 200-

watt, 6.6-ampere isolating transformers has been delayed because

of the defective regulator.

c. Seadrome, klshling

Improvement of Battery-Operated Seadrome Lights. Sample

amperites of reduced size have been obtained from the manufacturer
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and tested for use in these units 0 As shown in NBS Report

21A-3/56, these amperites were found to be satisfactory for this

application. Small relays have been purchased and a new circuit

model using the new amperites and small relays has been tested.

These tests were satisfactory and a laboratory model has now

been assembled which shows that the circuit using the small

amperite and small relays can be placed within the space that

is available in the container provided for the lamp circuit of

the current model seadrome light. TWo similar units constructed

with better workmanship are now being built for a test afloat.

Development of High-Intensity Seadrome Light. The cablefed seadrome light has been advanced by further analysis of

possible lamps and filters. A more efficient combination of an H23M5

mercury lamp and filter has been found which provides approximately

four times as many lumens of green light per watt as is obtainable

with an incandescent lamp and green filter.* However, when this

combination was analyzed from the standpoint of luminance,, it

was found that it would be less efficient than the incandescent

lamp and filter combination if the primary requirement is a light

of maximum candlepower with an optical system of fixed size. An

analysis has been started of the relative merits of reflectors,

lenses, and combinations of lenses and reflectors for use in the

cable-fed floating light.

Norfolk Installation. The tests of the 5OO-watt0 20-ampere,

PAR 56 lamps described above indicate that this lamp will be a satisfactory threshold light.

d. Carrier, Ughiing.

A third set of controls for waveoff lights has been assembled.

A study was made of the feasibility of constructing in the

National Bureau of Standards shops a mold for use in electroforming reflectors for the mirror landing aids system. While

the mold can be constructed here, it appears that a shop such as

that at the Gun Factory, which is equipped to handle work of this

size, could do the work more efficiently.

e. Lighted Suit for Landing Signal Officer. Details of the design of the LSO lighted suit equipment and

of the schedule of work on the contract have been discussed with

the contractor. A sample reel-fed wire for connecting the LSO

NBS Report 4449, Analysis of Mercury Lamps and Filter Combinations for Use as Aviation^Green Lights, prepared for the

Department of the Air Force.
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to the source of power has been received and examined* It has

been concluded that such an alternative to the method of connection called for in the specification does not appear desirable*

f. General Laboratory and Consultive Services , Technical advice and assistance have been given the Department of Justice in connection with the suit of the Nelsbach

Corporation claiming infringement by the Navy and Air Force of

the Bartow patent for high-intensity runway lights*

The preproduction TSM-11 Cable Test-Detecting Set was returned to the laboratory for check after a year’s use in the

field* No significant changes were found in the Power Supply or

Signal Generator units. An intermittently defective transistor

was found in the Amplifier-Indicator and the gain at 300 cycles

had increased significantly* The cause for this increase was

not found*

Marking of Tall Towers. The procurement specifications and

installation instructions for the identification lights and

hazard beacons for marking tall towers, reported last quarter,

have been incorporated in the report of the AGA Subcommittee

to the Technical Division of the Air Coordinating Committee*

Effective Intensity of Flashing Lights. A report has been

issued presenting a mathematical analysis of the effects on the

effective intensity Ie , computed from the Blondel and Key relation

produced by changes in the limits of the integral* The maximum

value of Ie

is obtained when the times tj and t2 are the times

when the instantaneous intensity, I, is equal to Ie

, Methods

which facilitate the computation of Ie , the checking of conformance to effective intensity specifications, and the computation of the visual range of flashing lights, are given in the

report. (NBS Report No. 4554)

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Kinorama. Four demonstrations of the kinorama have been requested and these have been provided. Two of these were for

personnel of the C.A.A., one for Mr, Jensen of the Air Transport

Association and one for Mr 0 Stevens, who was preparing an article

for publication in the Readers Digest. Since Mr, Stevens will

cover many other devices* it is not to be expected that much

reference will be made in his article to the kinorama 0 but the

Navy°s sponsorship was pointed out to him so that proper credit

could be given. The pilots and technical men all made favorable

comments on the potential utility of the kinorama as a device

for increasing the safety of landings under adverse weather conditions.

III, VISIBILITY AM) BRIGHTNESS TESTS0 SURVEYS, EVALUATION AND

ANALYSIS OF VISUAL LANDING AIDS, BASIC TESTS AM) EQUIPMENT AS A

FIELD SERVICE AT ARCATA, CALIFORNIA (TED NBS-AE-10011)

.

a. Airport Lighting and Markina . Approach Beacons. As reported last quarter, the stub

approach-beacon installation at the end of runway 13 produced dis

tortions in the localizer beam pattern. Therefore, a similar

installation is now being installed on runway 31. Views of the

trial installation on runway 13 are shown in figure 1. Figure

la shows the localizer antenna shelter and behind it, on a pole,

the approach beacon and the shield installed to reduce the distortion of the localizer beam pattern. Figure lb is a view

taken from the beacon showing the A-frame bracing the approach

beacon, the catwalk to the beacon, and the rear of the antenna

shelter. The guard rail on the catwalk had been removed because

of its effect on the localizer beam. Figure lc is a view of the

shielded approach beacon and its supporting structure. A wood

pole was used as the upper part of the structure instead of

steel, to reduce the effects on the localizer beam. The beacon

was mounted above the level of the bluff because it was felt

that putting the beacon much below the level of the antenna

shelter would create a hazardous condition.

Tests of the approach-beacon system, except for the testing

of the stub system , have been carried as far as is practicable

at the Field Laboratory. Installation of the following system

of approach beacons at one or more Naval Air Station for tests

of operational suitability is recommended. Beacons should be

installed at distances of 1000 and 2000 feet from the threshold

on the extended centerline of the runway. Each beacon should

be constructed on a base of the type now used for airway and
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airport beacons* The turntable should rotate at 12 rpm* Six

type 300 PAR 56/SP lamps should be mounted on the beacon turntable* The peak of the beams of these lamps should be 5° above

the horizon initially, Provision should be made so that the

elevation can be adjusted from 3° to 8° above the horizon* Ttoo

intensity steps* 100% and 10%* should be provided. An intensity

setting of 10% appears sufficiently low for use in good visibility at night; a third step0 about 2%* might be desirable

under some conditions of operation* The threshold-light system

of the runway should be strengthened* Installation of at least

five PAR 56 lamps with "approach-light” covers and green filters,

in wings outboard of the runway lights is recomnended* The

spacing between these lights should be not more than eight feet*

The beams of these lights should be elevated 5° and directed

outward so the inner edge of the beam is nearly parallel to the

runway centerline*

Airfield Lighting Maintenance Manual* The rework of the

Step-by-Step Troubleshooting Procedure has been completed and

the Procedure has been forwarded to Washington for editing and

preparation for reproduction. A series of troubleshooting

charts which outline the troubleshooting procedure in chart form

have been completed also. Each of these charts covers a specific

area of troubleshooting. The draft of the text accompanying these

sections is nearly complete and the preparation of a section on General Troubleshooting is being prepared* It is planned to

release these sections and obtain comments from the field before

proceeding with the other sections of the Manual,

b* Electric? LEimineering.

Survey Trip* In preparation for a contemplated survey of

Naval and Marine Air Stations on the West Coast* the questionnaire used in the survey made in 1953 on the East Coast has been

revised and expanded. The questionnaire will be used as a guide

in interviewing maintenance personnel and in analyzing the data

obtained*

Cable Fault Finding* The Handbook of Operations and Service

Instructions for the TSM-11 Test Set (NAVAER 08-20-501) has been

reviewed and several desirable modifications in the operation

instructions have been noted.
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c« Research on Visibility Measurements and Visibility , Sky Brightness, Since the replacement of the gear reducers

of the scan drives with heavier ones and the replacement of an

apparently defective drive motor which was reversing spuriously,,

the horizon sky-brightness meters have operated satisfactorily*

The self-balancing potentiometers intended to meter these units

were received from the factory in a damaged condition* A

Brown electronic recorder has, therefore,, been overhauled and

modified for use in recording sky brightness*

Slant Visibility Meter, The field and office installations

of this instrument are shown in figure 2* The projector and detector are installed in the approach zone about 1000 feet from

the threshold and 3000 feet from the recording equipment in the

office. This slant visibility measuring system consists of a fixed-beam ceiloraeter projector and detector modified so that

both rotate about colinear horizontal axes. The distance between

units is 250 feet* The detector is directed so that it receives

light from a section of the projector beam a known distance from

the projector* Since the angular relationships are constant

and since the distances from each unit to this section are constant,, interpretation of the measurements is simplified* Calibration is accomplished by comparing the response of this

instrument,, when the beam of the scanning system is horizontal,

with that of the transraissometer in the same area*

The 120-cycle signal from the detector is amplified by the

reeqrder-amplifier, rectified, and fed into a 5-milliampere

recorder. The gain of the amplifier is controlled by a selector

switch so that an output suitable for the recorder is obtained*

The drives of the field units and the recorder are coupled in

the following manner* The chart drive of the recorder is coupled

to a cam-operated switch which stops the chart after it has

traveled a distance equivalent to 90° of scan. The drive restarts when the direction of scan of the field units is reversed*

Thus, if the field units scan an angle of 90° + A°, the chart

drive will stop on each scan and will lag the field units by A°

on each scan but will never be in error by more than A°, Without this synchronizing feature, the error would be 2nA® where

n is the number of scans since the drives were synchronized.

The error. A, may be easily made small enough so that it is not

important on a single scan, but would not be made small enough

so that the cumulative error after a large number of scans is

unimportant*
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During this quarter the life of the projector lamps has been

unduly short* Part of these failures were caused by sticking of

the pressure regulator valve* Others appear to be due to defective

lamps* Leakage of water during the heavy rains of January into

the slipping assembly of the projector caused arcing across the

bakelite base on which the rings were mounted and burned the in°

sulation* A new base was fabricated and installed* It is planned

to install a Teflon base here so that arcing will not cause

failure of the insulation* In troubleshooting the instrument,

two deficiencies in construction were noted* The interlock breaks

only one side of the 230=volt power supply to the lamp transformer*

Therefore, if there is a ground, either low or high resistance,

near the center of the primary winding of the transformer, about

500 volts would be developed across the lamp socket with the interlock open* Also, the unguarded compressor fan is exposed when

the door of the compressor compartment is opened* There is no

interlock on this door to protect personnel* These deficiencies

are also present in some fixed beam ceilometers* The deficiencies

have been called to the attention of the manufacturer and the

Weather Services.

100% Setting Calibrator. The range of adjustment of the 100%

Setting Calibrator has been modified to adapt it to the projector

lamps and calibrator phototubes now being used. Checks are being

made of the permissible tolerances in the positioning of the

photocell of the calibrator*

d* PexittOflelo

Mr* George Davis, Laboratory General Mechanic, has taken a position with a local store and is working for the Field Laboratory on a very limited WAE basis. This has left the Laboratory

very much understaffed. It has, therefore, been necessary to do

some recruiting for replacements locally* TWo physics students

from Humboldt State College have been hired as WAE employees and

are working about half time. They will work full time during the

summer months and are expected to continue at the Laboratory on

a full-time basis after graduation.
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Approach

Beacon

Installation

on

Runway
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d. Recorder with selfsynchronizing unit attached

Figure 2. Slant Visibility Meter

nbs

THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods

for making measurements consistent with these standards; the determination of physical constants

and properties of materials; the development of methods and instruments for testing materials,

devices, and structures; advisory services to Government Agencies on scientific and technical

problems; invention and development of devices to serve special needs of the Government; and the

development of standard practices, codes, and specifications. The work includes basic and applied

research, development, engineering, instrumentation, testing, evaluation, calibration services, and

various consultation and information services. A major portion of the Bureau’s work is performed

for other Government Agencies, particularly the Department of Defense and the Atomic Energy

Commission. The scope of activities is suggested by the listing of divisions and sections on the

inside of the front cover.

Reports and Publications

The results of the Bureau’s work take the form of either actual equipment and devices or published papers and reports. Reports are issued to the sponsoring agency of a particular project

or program. Published papers appear either in the Bureau’s own series of publications or in the

journals of professional and scientific societies. The Bureau itself publishes three monthly periodicals, available from the Government Printing Office: The Journal of Research, which presents

complete papers reporting technical investigations; the Technical News Bulletin, which presents

summary and preliminary reports on work in progress; and Basic Radio Propagation Predictions,

which provides data for determining the best frequencies to use for radio communications throughout

the world. There are also five series of nonperiodical publications: The Applied Mathematics

Series, Circulars, Handbooks, Building Materials and Structures Reports, and Miscellaneous

Publications.

Information on the Bureau’s publications can be found in NBS Circular 460, Publications of

the National Bureau of Standards ($1.25) and its Supplement ($0.75), available from the Superintendent of Documents, Gov ernment Printing Office. Inquiries regarding the Bureau’s reports and

publications should be addressed to the Office of Scientific Publications, National Bureau of

Standards, Washington 25, D. C.
NBS