NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2301 April 15, 1954 3242

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 Marcjh 31, 1954

for

Bureau of Aeronautics Projects

TED No. NBS-AE- 10002

TED No. NBS-AE- 10006

TED No. NBS-AE-10007

TED No. NBS-AE- 10008

TED No. NBS-AE- 10011

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, re Approved for public release by the

uniesa permission is Director of the National Institute of

25,d.c, Such per. Standards and Technology (NIST)

cally prepared If tl on October 9, 2015

In part, Is prohibited

andards, Washington

port has been speclfliport for Its own use,

Development, Testing, and Evaluation of Visual Landing Aids

January 1 to March 31, 1954

I. REPORTS ISSUED

Report No . Title

3046 Visual Landing Aids Field Service Operation Progress

Report for the Period December 1, 1952 to November

30, 1953.

3094 Addenda to Instruction Book for Transmis some ter Set

AN/GMQ-10.

3136 Development and Testing of Visual Landing Aids,

Progress Report for the Period October 1 to December 31, 1953.

II. TED No. NBS-AE-10002. MISCELLANEOUS SERVICES IN CONNECTION

WITH FOG MODIFICATION AND VISIBILITY STUDIES.

Beam Setting of Type C-l Runway Light . The analysis of the use of

different beam settings in a type C-l runway light using a 200-watt

and a 500-watt lamp has been completed. A report covering this work

is nearly ready for reproduction. (NBS Test Report 21P-5/54)

Lights for Night Field Carrier Landing Practice . A report describing

tests of an experimental battery-operated unit has been completed and

is now ready for reproduction. (NBS Test Report 21P-4/54)

Characteristics of Retroreflectors . Measurements of specific intensity of retroreflectors have continued. The basic data are now nearly

complete. All measurements made to date have been analyzed and a report is being drafted.

III. TED No. NBS-AE- 10006. DEVELOPMENT OF TRANSMI SS OMETERCEILOMETER INTENSITY CONTROL SYSTEM.

Addenda to Instruction Manuals In addition to the five Addenda previously prepared, a sixth addendum, "Modification of the Indicator

to Permit Direct Operation of the Pulse Amplifier,” has been prepared.

These Addenda have been issued as NBS Report No. 3094.
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Specifications. Assistance has been given the Aerology Section,

Bureau of Aeronautics, in the preparation of an interim specification

for the procurement of transmissometers.

Intensity-Setting Indicators , A brief study has been made of the

feasibility of using in the control tower at Patuxent River a meter

specially calibrated to indicate the proper intensity settings of

runway and approach lights. The meter would be operated from one of

the regular transmissometers. One of the principal difficulties in

using such an arrangement is the crowding of the high intensity settings for night conditions at one end of the meter scale. Another

difficulty is the complexity of the scale if both high and low transmissometer ranges are used and if runway- and approach-light intensity settings are indicated on the same meter.

100% Setting Calibrator . An improved 100% setting calibrator was delivered to Areata for field tests. Trials there indicated that

the dalibration of this instrument was not as stable as desired.

Tests are now being made in Washington on a similar unit. to determine

whether this effect is inherent in the instrument, is the result of

a defective component, or the result of errors introduced by the

calibration technique. These tests indicate that considerable care

is needed to prevent errors from stray light affecting the calibration and that when these errors are eliminated, the stability of

calibration is satisfactory.

IV. TED No. NBS-AE- 10007. RESEARCH ON VISIBILITY AND

INTENSITY CONTROL OF VISUAL LANDING AIDS.

Marking of High Towers . Further analysis has been made of the problem of marking high radio and television towers. Computations are now being made of the comparative visual range of towers as now

marked, of large painted markings on the ground, and of the lighting

system proposed by the National Bureau of Standards. The Bureau

proposal was described at a meeting of the A.G.A. Subcommittee.

V. TED No. NBS-AE- 10008. DEVELOPMENT AND TEST OF

SEALED-REFLECTOR APPROACH LIGHT LAMPS.

Qualification tests are being made on a group of eight preproduction samples of 399-watt approach-light lamps received from

the Westinghouse Electric Company. The lamps meet the intensity,

beam spread, and life requirements of the procurement specification.
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A report giving the results of this test has been prepared and will be

issued as soon as the life test is completed. (NBS Test Report

21P-6/54)

VI.. TED No. NBS-AE-10011. FIELD SERVICE OPERATION.

Progress Report . A progress report describing the background of the

Operation, the facilities at the field location, the tests in progress,

and the expected use of the data obtained, and giving preliminary

results, has been issued. This report covers the period December 1,

1952 to November 30, 1953. (NBS Report 3046)

Survey of Naval and Marine Air Stations. A report giving the results

of a survey of the visual landing aids at eleven Naval and Marine

Air Stations has been prepared and is being edited.

Field Maintenance Manual for Airfield Lighting Systems . Preparation

of this manual has been given priority over the other tasks of the

field group. Considerable time has been spent in organizing the

material to be presented and to the development of a plan of attack.

Particular attention has been given to the step-by-step troubleshooting procedures and charts.

Approach Beacons . The installation of two approach beacons in the

approach to runway 31 has been completed. The beacons are located

1000 and 2300 feet from the runway threshold. They are provided with

high and low intensity settings so that the possibility of glare on clear nights is reduced. No flight tests have been made to date.

However, as a result of casual observations, one of the pilots of

Southwest Airways has requested that a beacon be placed on the approach

to runway 13, thus indicating the utility of the beacons.

Transmissometrv . The study of the errors in transmission measurements

introduced by scattered light has been continued. The differences in

the readings of the two parallel transmissometers due to natural con- ditions masked the errors resulting from scattered light. Therefore

an indirect technique is now being used. One transmissometer, wellbaffled, is used to measure the direct transmission. Another transmissometer, with a disk midway between the projector and receiver to

block out all direct light, measures the scattered light and, hence,

the error which would be introduced into measurements made with an unbaffled instrument. Results to date indicate that the errors are not serious.
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Tests in Fog. Although fog is not usual during this reporting period, there was a two-week period in which dense fogs were frequent.

Tests similar to those described previously were conducted during

this period.

Analysis of Data . Data obtained during the fog season are being

analyzed.

Future Work . The frequency of fog during the next reporting period

is expected to be low. Emphasis will, therefore, be placed upon the

analysis of the test work and the preparation of reports. Work on the maintenance manual will occupy a considerable portion of the

time. Tests will be continued when suitable weather conditions

occur.