i

NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

0201-20-2301 February 15f 1956 4533

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

October 1 to December 31, 1955

for

Bureau of Aeronautics Projects

TED No. NBS-AE-10002

TED No. NBS-AE-10011

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The publication, r, Approved for public release by the

unless permission i director of the National Institute of

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

cally prepared If I Q n October 9, 2015

In part, is prohibited

tandards, Washington

sport has been specifieport for its own use.

Development, Testing, and Evaluation of

Visual Landing Aids

October 1 to December 31, 1955

Report No.

I. REPORTS ISSUED

Title

4343 Photometric Tests of 21 Colored Retrorefleetive

Samples

4368 Development, Testing, and Evaluation of Visual

Landing Aids, Consolidated Progress Report for the

Period July 1 to September 30, 1955

4463 Current-Intensity, Voltage-Intensity, and CurrentVoltage Characteristics of Runway- and ApproachLight Lamps

21A-6/55 Type II Angle-of-Approach Light (Letter Report)

21P-17/55 Photometric Tests, Type M-l Elevated Runway Marker

Lights

Purpose, Requirements, and Installation Instructions

for the Identification Lighting System for Tall

Towers

Procurement Specifications for Identification Beacons

for Tall Towers

Purpose, Requirements, and Installation Instructions

for the Obstruction Lighting System for Tall Towers

Procurement Specifications for Hazard Beacons for

Tall Towers

Procurement Specification for Lighting Suit Equipment, Landing Signal Officer

Malfunctions of Type NC-3 Constant Current Regulators (Memo Report)
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II. RESEARCH AND DEVELOPMENT, LABORATORY TESTING, AND CONSULTATION

SERVICES IN CONNECTION WITH VISIBILITY, AIRFIELD LIGHTING, AND

FOG MODIFICATION PROBLEMS (TED NBS-AE-10002).

a. Visibility Meters and Their Application ,

Tra nsmis someters. An experimental phototube similar in construction to those described in Report No. 4368 but having a modified S-4 surface has been received from the Continental Electric Company and is being tested. The spectral response of the

S-4 surface is preferable to that of the S-l surface now being

used since the S-4 response is closer to the spectral response of

the human eye.

The report "Theory of the Tra nsmis some ter Photometric System"

has been completed and is being edited. This report provides a more complete theoretical background than it was possible to include in the instruction manual.

Checks have been made of the second order effects of deviations

from linearity of the photocells used in the 100%-setting calibrator

and a method of calibrating and correcting for these effects has been

developed. It was found that the Weston photronic cells had insignificant deviations.

Brightness Meters. An illuminometer for obtaining the ratio of

the indirect illumination to the total illumination incident on the

horizontal plane has been constructed. This ratio is obtained by

rotating a shadow bar periodically so that the illuminometer will be

momentarily shielded from the sun, thus giving a measurement of the

indirect illumination. The unit has been sent to Areata for use.

b. Airfield- Lighting, and Marking . Runway Marking, Sample material for runway marking has been

obtained from J. W. Neff Laboratories, Inc. Tests on this material

are being delayed until materials from other manufacturers are

received.

Runway Lighting. An experimental retractable runway light

manufactured by Miller Research Laboratory has been delivered for

test.

Taxiway Lighting. A study has been made of the intensity distribution of the Type M-l light with clear asymmetric and blue

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symmetric lenses and of the intensity-current characteristics. The

results are reported in NBS Test Report 21P-17/55.

Runway Distance Markers, PAI$ 3(6 lamps of several voltages and

wattages have been obtained for study as possible lights for distance markers. A study will be made of the intensity of these lamps

when operated singly or in series or parallel combinations from

30/45-watt and 200-watt, 6.6-ampere isolating transformers. Particular attention will be given to the change in intensity as the primary

current is varied in order to determine the combination of lamp(s)

and transformer which will provide the highest illumination at low

brightness settings and satisfactory life at high brightness settings.

Control of Constant-Current Regulators. The control relays for

a safety circuit which will put constant-current regulators on

brightness step 4 instead of step 5 whenever the current on step 5

exceeds 6.8 amperes have been received. The relays have been assembled into a control unit. The unit has been sent to Areata where

it will be installed for service testing.

Heliport Lighting. A preproduction sample of an approachangle light was received from the Forways Industries Inc. for tests

to determine if it complied with the requirements of the specification. The tests showed that it complied except for specific

deficiencies which the manufacturer can readily correct. The results

were summarized in a letter report under Test No. 21A-6/55.

Intensity-Current-Voltage Characteristics of Lamps. The increasing complexity of the problems of intensity control has

increased the need for information on the relative intensity characteristics of lamps used in approach, runway, and taxiway lighting

as a function of the applied voltage or current. In addition more

information on the effects of color filters is required. Therefore,

a study has been made of the intensity-current-voltage characteristics of lamps of the types generally used in airfield-lighting

systems and of the effect of color filters upon the relative intensity of these lamps. The results of this study have been reported

in NBS Report 4463.

c. Seadrome Lighting.

Norfolk Installation. Arrangements have been made with the

General Electric Company to obtain experimental 500-watt, 20-ampere,

PAR 56 sealed-reflector lamps for test. The beam pattern of these

lamps will be similar to that of the 399PAR approach-light lamps.
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Development of High Intensity Seadrome Lights. As indicated

in Report 4368v a combination of mercury lamp and filter was being

tested as a possible source for the cable-fed seadrome light. The

filter which was then undergoing tests proved to be inefficient

and a second filter is now being tested.

An improved starting circuit has been designed for batteryoperated seadrome lights. The new circuit utilizes rectifiers^to

channel the starting and extinguishing signals to the correct relays

which take the place of the switches in the present circuit. The

necessary holding time required for starting and extinguishing has

been provided by the use of capacitors. The circuit has been

tested with the lamp at 0°F in a cold chamber and gave about the

same proportion of starts as the present circuit. The effect of

wave action on the relays should be tested and, if possible, the

size of the components of the circuit should be reduced so that it

will not be necessary to increase the size of the circuit box in

order to use the new circuit in the buoys now in service. With the

use of this circuit, a virtually instantaneous contact from a very

light rod can be utilized in place of the present cumbersome and

somewhat prolonged boathook manipulation. It should, therefore,

decrease considerably the time required for starting, or extinguishing, a line of lights since it may make it unnecessary to stop the

boat at each buoy.

d. Carrier Lighting . IWo sets of controls for wave-off lights for the mirror landing aids system have been assembled and shipped to the Ue S.S.

Bennington. When the wave-off switch is closed, these controls

turn off the source lights and as many of the inboard datum lights

as desired and flash tbe wave-off lights 90 times a minute. Adams

and Westlake mercury relays are used as the primary controls.

Intensity distribution measurements were made on a breadboard

night field carrier landing practice light unit constructed by the

Falge Engineering Corporation. The results, which were reported

directly to the manufacturer, indicated that the plastic spreadlenses which were installed could not be made to produce the

specified intensity distribution. Ose of a glass spread-lens

designed for this light was recommended.
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e. Lighted Suit for Landing Signal Officer . An experimental specification has been prepared for use in

procurement of lighted suit equipments, and has been issued by

BuAer under the title, "Lighted Suit Equipment, Landing Signal

Officer," XAE-127, 4 November 1955, Negotiations are under way

for procurement.

At the augjgestion of an LSO in the fleet, the use of a reelfed wire to connect the LSO to the control box is being investigated,

f. General Laboratory and. Consultive Services . Specific Intensity Measurements of Retroreflectors. NBS Report

4343, Photometric Tests of 21 Colored Retroreflective Samples, has

been completed and released. This completes the present program of

study of the characteristics of retroreflectors.

Color Specifications, A report comparing the requirements of

the United States and International Specifications and Standards

for Signal-Light Colors has been drafted in accordance with a request of the Airport Lighting and Marking Panel, This report

contains two tables and four diagrams and is now in process of

being reproduced,

Kinorama, There has been no activity in connection with the

kinorama during the past quarter because no funds have been available for this purpose, but the problem of utilizing this potentially

very valuable equipment remains,

III. VISIBILITY AND BRIGHTNESS TESTS, SURVEYS, EVALUATION AND

ANALYSIS OF VISUAL LANDING AIDS, BASIC TESTS AND EQUIPMENT

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

.

a. Airport Lighting and Marking . Approach Beacons, An approach beacon was installed at the end

of runway 13 and with the assistance of CAA maintenance and flight

personnel the effects ^f this installation upon the ILS localizer

pattern were checked. Because of the bluff at the north end of the

field, it was necessary to install the approach beacon only 75 feet

behind the localizer antenna shelter. Even at this distance from
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from the antenna, a rather extensive structure was required to support the beacon since the antenna shelter is only 25 feet from the

edge of the bluff. Although the supporting structure near and

above the level of the top of the bluff was made of wood, excessive

changes in the localizer pattern were produced. The magnitude of

these changes varied with the moisture content of the soil and the

wood in the supporting structure. The time available for adjusting

the antenna lines and flight checking was limited by the weather.

Satisfactory adjustment of the localizer beam pattern was not obtained so the beacon and its tower were temporarily removed. It is

believed that satisfactory adjustment can be made if sufficient

time is available. The installation and testing could not have

been accomplished without the excellent cooperation of the Humboldt

County Department of Aviation who provided and installed the tower

and of CAA personnel, especially Mr, Cimmery, the MaintenanceTechnician in Charge, who put in many extra hours adjusting the

localizer pattern.

Airfield Lighting Maintenance Manual. The draft of the

General Trouble-Shooting Section of the Airfield Lighting Maintenance Manual has been completed. The Trouble-Shooting Chart has

been revised and a tentative final diagram is nearly complete. The

Step-by-Step Procedure is nearly complete, but some revisions

required because of the revisions in the Trouble-Shooting Chart are

being made.

Regulators. Three type NC-3 regulators were received and have

been installed on the runway circuits, replacing 5-kilowatt regulators. The additional capacity of these regulators makes possible

tests of threshold lighting systems, runway turnoff markers, etc.,

which require more power than had been available previously. Also,

it is now possible to operate the high-intensity runway lights at

the designed brightness settings so that measurements of runway

brightness and optimum intensity settings will be more meaningful.

Two of the regulators were found to have broken connections

within the lower tank. The units were removed from the tanks and

the breaks repaired. During the time the units were removed from

the tanks, a check of the general workmanship showed that at one

place the spacing between the high-voltage wiring and the control

wiring was too small. These deficincies have been reported in a memorandum report*
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Over-current Protection. The controls for a safety control unit

for constant-current regulators have been received and assembled.

This unit is designed to put constant-current regulators automatically

on brightness step 4 instead of step 5 whenever the current on step 5

would exceed 6.8 amperes. The control unit has been installed in

the control circuit of one of the new NC-3 regulators. Functional

operation of the unit has not been determined yet.

b. Electrical Engineering.

Cable-Fault Finding. Some tests of the TSM-11 Cable TestDetecting Set have been made under conditions very unfavorable for

its good performance in order to determine its limitations. These

tests have included tracing ungrounded shielded cable, checking for

grounds in shielded telephone cable, checking parkway-type cable in

conduit and in close proximity to power lines. The pick-up from the

power lines was greater than expected, indicating that the amplifierindicator may have become detuned. The unit will be returned to

Washington for checking.

c. Research on Visibility Measurements and Visibility . Sky Brightness. Equipment for measuring horizon sky brightness

illumination on the horizontal surface, and illumination on a vertical

surface, has been installed in the approach zone, using an old AGA

tripod tower installed for this purpose about 1500 feet from the runway threshold. The instrument for determining the ratio of indirect

to total horizontal illumination has also been installed. The

signals from these instruments have been brought into the Laboratory

where they will be recorded. Only part of the measurements can now

be recorded as two of the self-balancing potentiometers intended for

this use were damaged in shipment from Washington and are now being

repaired. The scan drive for the horizon sky brightness meter has

caused some difficulty. The original gear reducer has been replaced

with a more rugged gear box. The causes of spurious reversing and

starting in the wrong direction of the type SMY motor driving the

scan are being investigated.

Slant Visibility Meter. This unit has operated satisfactorily

during most of the period. Considerable data have been obtained

in periods of fog, low ceilings and low visibilities. Late in the

quarter the slip-ring carrying the current to the projector lamp
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arced over and burned out. It is being repaired. Lamp life has

been very short. Checks are being made to determine if the fault

is in the projector or in the lamps,

Transmissometry. The linearity of the 100%=setting calibrator

has been checked and found satisfactory. The calibrator has been

checked against the transmissometers on the field with very satisfactory results. These results indicate that by using the calibrator, a transmissometer can be adjusted so that the error in the

100% setting will be less than 1% without the necessity of waiting

for a period of very clear weather.

Measurements of the errors introduced by scattered light have

continued. The red-sensitive phototube in the receiver has been

replaced by a blue-sensitive phototube to determine what effect

spectral sensitivity has on the errors.

Equivalent Intensity of Flashing Lights and of Composite Units.

Replacement parts for the Westinghouse Krypton light have been

ordered.

Facilities. During this quarter control and power cables

abandoned by LAES were further salvaged and utilized by the installation of test equipment.

During late December the Humboldt County area experienced the

worst floods in its history. Neither the floods nor the heavy

rainfall which preceded them caused any damage to the facilities

or installation of the Field Laboratory. However,, the homes of

many of the residents of this area were washed away or inundated.

Extensive air rescue operations were conducted from the Areata

and Rohnerville Airports by helicopters and fixed wing aircraft

to pick up flood victims from the floating houses and other

locations accessible only by air, and to drop medical supplies and

food. During the period December 23 to 27 a "Rescue Center" from

which the air rescue operations were coordinated was set up in

our Laboratory office. NBS radio equipment provided the only

communication link between this Rescue Center,, the Coast Guard

cutter "Balsam” and the Rohnerville Airport. Throughout this

period NBS personnel operated and maintained the radios at Rohnerville and Areata Airports, established temporary interphone circuits

at Areata Airport between the Rescue Center,, the CAA Ihsac Station,

and the refueling area, and assisted the operation of the Rescue

Center in every way possible, working virtually around the clock.