NATIONAL BUREAU OF STANDARDS REPORT

3260

REPORT OF A SURVEY OF VISUAL LANDING AIDS

By

James E. Davis

<nb|>

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 of

the divisions and sections engaged in technical work. In general, each section is engaged in specialized research, development, and engineering in the field indicated by its title. A brief description

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

cover of this report.

Electricity. Resistance and Reactance Measurements. Electrical Instruments. Magnetic

Measurements. Electrochemistry.

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Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry.

Inorganic Chemistry. Electrodeposition. Gas Chemistry. Physical Chemistry. Thermochemistry.

Spectrochemistry. Pure Substances.

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Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Polymer Structure. Organic Plastics. Dental Research.

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Electronics. Engineering Electronics. Electron Tubes. Electronic Computers. Electronic

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Services. Frequency Utilization Research. Tropospheric Propagation Research. High Frequency

Standards. Microwave Standards.

^Office of Basic Instrumentation ^Office of Weights and Measures.
HAT10MAL BUREAU OF STANDARDS REPORT

NBS PROJECT MBS REPORT

0201-20-2327 3260

May 10, 1954

REPORT OF A SURVEY OF VISUAL LANDING AIDS

By

James E. Davis

Photometry and Colorimetry Section

Optics and Metrology Division

Project No. TED NBS AE-10011

of the

Visual Landing Aids Section

Aifborne' Equipment division

Bureau of Aer&fra uti<r$r

Department of the Navy

Washington 25, D.C.

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

The pubiica Approved for public release by the

unless perm Director of the National Institute of

25, d.c. s Standards and Technology (NIST)

caiiy prepa on October 9, 2015

hole or in part, is prohibited

au ofStandards, Washington

ich a report has been specifiicular report for its own use,

REPORT OF A SURVEY OF VISUAL LANDING AIDS

TABLE CF CONTENTS

Paragraph Page

ABSTRACT 1

1. INTRODUCTION 1

2. SURVEY OBJECTIVES AND METHODS 2

3. DATA OBTAINED 3

3. 1 INSTALLATION AND PERFORMANCE OF EARTH BURIAL CABLES, 3

CABLE CONNECTORS," AND SPLICES

3.1.1 5000-Volt Polychloroprene- Jacketed Cable 3

3.1.2 3000-Volt Polychloroprene-Jacketed Cable 4

3.1.3 3000-Volt Lead-Sheathed Cables 4

3.1.4 Cable Connectors and Splices 4

3.1.5 Isolating Transformers 4

3.2 METHODS OF LOCATING AND REPAIRING FAULTS IN CABLES 5

3.2.1 Isolation 5

3.2.2 Model OBB Cable- Detecting Equipment 5

3.2.3 Stewart Type L Cable Tester 5

3.2.4 Line Locators 6

3.2.5 Other Instruments 6

3.2.6 Remarks 6

3.3 DIFFICULTIES ENCOUNTERED IN THE INSTALLATION, MAIN- 6

TENANCE, OR OPERATION OF OTHER VISUAL LANDING

AIDS

3.3.1 M-l Lights 7

3.3.2 AN-L-9 Lights 7

3.3.3, Indication of Inoperative Sections 7

3.3.4 Lamp Burnouts 7

3.3.5 Lack of Information 8

3.4 METHODS OF INSTALLING, TESTING, AND MAINTAINING 8

EQUIPMENT

3.5 ADDITIONAL COMMENTS 9

3.5.1 Control Panels 9

3.5.2 Taxiway Lighting Systems 10

3.5.3 Micellaneous 10
TABLE OF CONTENTS (cont.) 4

Paragraph Page

4. SUMMARY AND RECOMMENDATIONS 11

4.1 MAINTENANCE PROCEDURES AND EQUIPMENT 11

4.1.1 Establishment of Regular Maiqtenance Test Pro- 11

cedures and Records

4.1.2 Assignment of Full Time Personnel 11

4.1.3 Recommended Maintenance and Test Equipment 11

4.2 CABLE AND CABLE CONNECTORS 12

4.3 RUNWAY AND TAXIWAY LIGHTING 12

4.3.1 Improvement of Water Removal from Semi -Flush 12

Lights

4.3.2 Prevention of Damage to Elevated Lights 13

4.3.3 Correction of Lamp Failures Due to High Current 13

4.3.4 Group Lamp Replacement 13

4.3.5 Taxiway Lighting 14

4.3.6 Intensity Setting 14

4.3.7 Indication of Runway- and Approach-Light Operation 14

4.4 GENERAL 14

4.4.1 Provision for Emergency Escape from U-Shaped Vault 14

4.4.2 Additional Surveys 15

4.4.3 Higher Echelon Inspection of Visual Landing Aids 15

Appendix I Survey Questionnaire 16

Appendix II Summary of Replies to Survey Questionnaire 20

ii
REPORT OF A SURVEY OF VISUAL LANDING AIDS

By

James E. Davis

ABSTRACT

This report presents the results of a survey of the visual

landing aids at eleven Naval and Marine Corps Air Stations. Particular attention was given to airfield lighting difficulties and

maintenance problems and methods. The survey was accomplished by

interviewing the personnel performing the maintenance as well as those in charge and by completing a survey form for each station.

Each installation is a special problem in itself, but some of the

problems are sufficiently similar to warrant recommendations which

may improve efficiency in operations and maintenance. The survey

can serve as a basis for preparing maintenance manuals or instructions and in making preparations for any future surveys of a similar

nature.

1. INTRODUCTION

The use of visual landing aids in conjunction with the elec- t fcronip and other instrumental aids for landing, taxiing, and takeoff during low visibility conditions is increasingly important. With

the advent of very high candlepower approach- and runway-lighting

systems with their related specialized regulators, controls, etc.,

the problems of maintaining visual landing aids have become a specialized phase of airport operation. These systems are becoming

increasingly more complicated and difficult to maintain. Some stations report that an abnormal amount of maintenance is required to

keep this equipment operating satisfactorily while other stations

appear to have very little maintenance trouble. A survey of various

stations was therefore deemed desirable.

Accordingly, the Airborne Equipment Division, Bureau of Aeronautics, by letter of 7 April 1953, AER-AE-101, serial 47164,

requested the National Bureau of Standards to make such a survey

under Project TED No. NBS-AE-10C11 and recommended the stations to

be visited. (The stations visited are listed in Appendix II.)
-2-

I

From the results of this survey it is possible to make recommendations to reduce maintenance. The reports from the men who are assigned the maintenance of these aids are helpful in determining

the need for modification of existing equipment, in the design of new equipment, and in determining the need for specialized and com- mon maintenance instruments and tools.

2. SURVEY OBJECTIVES AND METHODS

The object of the survey was to obtain data on the following

items

:

a. Installation and performance of earth -burial cable,

cable connectors, and splices.

b. Methods of locating and repairing faults in cables.

c. Difficulties encountered in the installation, operation,

and maintenance of other visual landing aids equipment.

d. Methods of installing, testing, and maintaining equipment.

The survey included personal interviews with the electricians

who accomplish the maintenance of these visual landing aids, Public

Works Officers, Operations Officers, and others interested in the

problem of airfield lighting maintenance. A survey form, Appendix I, was prepared to facilitate the interviewing and the tabulation of

information.

Every effort was made to obtain unbiased replies to the questions of the survey form, particularly to those related to cable

and equipment faults. However, several factors enter into answers

to questions of this type. If no records are kept and faults are infrequent, the actual number of faults over a period of several

years is not easy to determine. If some particular piece of equipment or cable has recently caused trouble, there may be undue

emphasis on that item. Also, if potential faults are located and

corrected before failure by adequate preventive maintenance, they

cannot be included.

A demonstration of the use of a Navy model OBB Cable Detecting

Equipments Wilkinson Line Locator, and a Takk Insulation Tester was made at each of the stations. A copy of NavAer 19-1-517 Airport

Field Lighting Design Manual and a set of current Airfield Lighting Design Drawings not included in NavAer 19-1-517 were left at

each station for future use. Other technical information and

assistance was given to the personnel at each station.
-3-

3. DATA OBTAINED

Appendix II is a tabulation of replies to the questions of the

survey form given in Appendix I. However, in view of the limited

number of stations and the lack of adequate records, the findings

cannot be readily summarized from a table of data. For this reason,

many individual problems are included in the discussion below.

3.1 INSTALLATION AND PERFORMANCE OF EARTH BURIAL CABLES,

CABLE CONNECTORS, AND SPLICES

The number of cable faults varied widely from station to station, from none in five years to one fault per week. The average

for all stations is about eight to ten a year.

. . 3.4* I. 5000-Volt Polychloroprene- Jacketed Cable

Most stations visited were in the process of installing or had

just recently completed the installation of new runway- and taxiwaylighting systems. Therefore it was not possible to determine the

common faults of cable installations using the new 5000-volt, polychloroprene-jacketed, direct-burial cable. Patuxent River, Maryland,

had had in operation for more than a year one runway- and one approachlighting system using the new type cable and connectors. Several

faults had occurred in a feeder line using this type of cable between

the main vault and an underground vault in the field; however, here

the cable was connected continuously to a 2400-volt power source instead of being used for the intermittent service for which it was

intended. Faults in this line were confined to an area near the

intersection of runways 2, 6, and 9. The same types of trouble have

been experienced in this general area with other types of directburial cables and the maintenance personnel estimated that the majority of cable faults at that station [have occurred in this. area. Since no records had been kept, it could not be determined whether

these faults were caused by lightning, soil-chemical action, or by

other causes; however, one fault was attributed to lightning. No

soil analysis had been made, so the relation of the soil condition

to the faults could not be determined. Atlantic City reported that

three cable faults occurred in the new cable as a result of lightning strokes and that in each case the strokes were observed by

tower personnel. The few cases of cable failures in the new 5000-

volt cable other than those noted above were attributed to faulty

initial installation.
-4- (

3.1.2 3000-Volt Polychloroprene- Jacketed Cable

In the 3000-volt polychloroprene-jacketed cable no unusual

faults were reported except at Patuxent .RiVer where numerous failures

in this type of cable have occurred. The causes of trouble were

undetermined. However, other types of cable also have had the same types of failures in the same area of the field. Some of the

faults at other stations were attributed to faulty installation

and a few were attributed to lightning.

3.1.3

3000-Volt Lead-Sheathed Cables

Most stations with the 3000-volt, lead-sheathed cable had had

considerable maintenance trouble. This cable had been installed

for several years and is now being replaced at most stations. In

general, the cable had just deteriorated, but Anacostia and Cherry

Point have diagnosed the cause of the failures as chemical or soil

action. Johnsville had had very little trouble.

3.1.4

Cable Connectors and Splices

No cable connector faults that could be attributed to the con- nector itself were reported. The only trouble experienced with the new connectors was that one above ground during construction of a manhole was damaged by a vehicle. The problem of having to remove dirt from the female connectors of runway lights was reported.

Only isolated cases of trouble have been experienced with conventional splices in the synthetic rubber-type cables. Some stations

that had considerable trouble with lead-sheathed cable also reported

trouble with the splices.

3.1.5

Isolating Transformers

No trouble was reported from isolating transformers after re- placing any of the bad units in the initial installation. Two stations reported a number of failures of these transformers shortly

after installation, but that no failures had occurred after these

first defective transformers were replaced.
-5-

3.2

METHODS OF LOCATING AND REPAIRING FAULTS IN CABLES

3.2.1 Isolation

Only three stations had any cable-fault locating equipment,

so the most common method of fault locating was by isolation.

Fault locating by this method is both time consuming and expensive. Along runway and taxiway series circuits, between the light

units, this method is reasonably satisfactory if there are no more

than two faults in the circuit.

3.2.2

Model OBB Cable- Detecting Equipment

At the two stations where fault-locating equipment was available, faults were located with a minimum of effort and time. Both

Patuxent River and Oceana were using a Navy model OBB Cable Detecting Equipment (Specification MIL-C-16163 (SHIPS) 15 March,

1951) with good results. Faults from shorts or from low-resistance

grounds in cable runs over 5000 feet long were located to within

a distance of a few feet. Some experience is needed by the maintenance personnel before good results can be obtained. However,

the results obtained with this equipment were found to be very

satisfactory after it had been used a few times.

3.2.3

Stewart Type L Cable Tester

Norfolk had constructed a pickup amplifier for use with a Stewart Type L Cable Tester manufactured by Kellogg Switchboard and

Supply Company. This equipment, commonly called a "woodpecker," has

a signal frequency estimated to be about 25 to 50 cycles per second.

The signal can be interrupted for identification. It is used ex- tensively by telephone personnel. The maintenance personnel did

not feel the modified pickup amplifier was satisfactory, especially

after having compared it on several occasions with the OBB Cable

Detector at Oceana.

Oceana personnel had brought their OBB to Norfolk to assist

in locating cable faults in a paved area and since that time Norfolk

has abandoned the use of their "woodpecker. w Patuxent River had

attempted to use a "woodpecker" several times but with no success.
-6- 3,2.4

Line Locators

Cable and "Treasure” locators, similar to the Wilkinson Line Locator, that operate at high (radio) frequency have been satisfactory for locating buried conduits and cables but have not been

useful for cable fault detection. Tests on this type of equipment for use as cable-fault detectors indicate that the signal

would not stop at the location of a ground or short but would

"ride" through.

3.2.5

Other Instruments

All stations, r except (one which reported only a voltmeter and

an ammeter, had available for airfield lighting maintenance personnel use an ohmmeter, voltmeter, ammeter (usually the clamp-on

type), and "megger" (500, 1000, or 2500 vdc) for determining cable

condition and fault locating. One station had installed ammeters

in the output circuit of the regulators. This provides a con- venient method for checking operation of the regulators. One

station had available for use a recording ammeter and voltmeter.

3.2.6

Remarks

In general, at locations where no records were kept or no regular resistance measurements were made, cable faults were

more frequent. At stations where records were kept and regular

resistance measurements were made, potential cable faults were

detected before an outage of the circuit occurred. This has reduced the number of faults reported from these stations. It is

of interest to note that at the station with the most faults,

maintenance personnel depended entirely on the use of a clamp-on

ammeter and voltmeter for maintenance.

3.3 DIFFICULTIES ENCOUNTERED IN THE INSTALLATION, MAINTENANCE,

OR OPERATION OF OTHER VISUAL LANDING AIDS

Difficulties encountered during installation could not be determined since most of the installations were made by contractors

and their comments were not obtainable. The difficulties en- countered in maintenance and operation may be common to several

stations or they may be reported at only one or two stations.

All difficulties tepOrted which are considered sufficiently important to need further study or which may be encountered at other

stations at present or in future installations are discussed below.

See also Appendix II.
-7-

3.3.1

M-l Lights

The most frequently encountered complaint was that the type

M-l lights would not stand up under jet and propeller blasts.

These units were being blown off of the mounting clips that hold

them down, particularly at turns, warm-up areas, and where they

are used for threshold markers. In one instance where they were bolted to the clips, the cones collapsed under jet blast.3.3.2

AN-L-9 Lights

A common complaint at all stations where the AN-L-9 semiflush lights are installed without isolating transformers was

that water collects in the bases, causing grounds. This difficulty is gradually being overcome by replacement with elevated

lights and isolating transformers. In maintenance of present installations of this type, several solutions have been tried but none is satisfactory for all cases. Quonset Point has been suc- cessful in keeping the water out by using double gaskets between

the base and top assemblies. Frequently the water seeps in through

the lead-sheathed cable, as was found at Anacostia, and any permanent repairs would require replacing the cable.

3.3.3

Indication of Inoperative Sections

The Operations Officers at several stations wanted some means of

positive' indication:, to the; Controli tower epferattor tbcshoto: when^tr section of runway lights is inoperative since it is very disconcerting

to a pilot, after landing in low visibility, to find no runway

lights for guidance. A method of indication other than visual inspection from the control tower is required since, in periods of

low visibility when the need for the lights is the greatest, sec- tions of lighting systems cannot be seen from the tower. At some stations, woods, buildings, changes in ground elevation, etc. ob- scure parts of the runway even in clear weather. There is a similar need for positive indication of the operation of approach-light

systems since the distance from the control tower to the approach

lights is generally greater than the distance to the runway.

3.3.4

Lamp Burnouts

One common complaint reported in new installations was that

the output current of the new type NC-3, 15 -kilowatt, Hevi Duty
-8-

regulators operating at near full load increased as lamps began to

burn out when the lamps were operated through isolating transformers. When approximately 15% to 20% of the lamps in the circuit

have burned out, the current has increased to such a level that the

balance of the lamps in the circuit burn out when the system is

operated on the 100% setting. When the initial lamp load is about

half the capacity of the regulator, this condition does not seem to

exist.

3.3.5 Lack of Information

A complaint which, although not an equipment fault, is important from the standpoint of maintenance, iSs the difficulty of

supply of standard stock items. The items do not seem to be listed

in ASO catalogs, or few people know how to find the stock number by

the item description. In some instances maintenance personnel had

prepared requisitions which were returned for additional information

because the stock number given was not found in current catalogs.

The fact that current information is not being passed on to the

maintenance personnel was apparent. In some cases standard stock

items were being purchased from manufacturers rather than through

ASO. Only a few of the maintenance personnel had Technical Orders

or Standard Drawings of equipment, and in some instances they were

unaware of the existence of such drawings. and technical orders.

3.4 METHODS OF INSTALLING, TESTING, AND MAINTAINING

EQUIPMENT

Since most sizable installations were made by outside contractors, details of the methods of installation were unobtainable.

Generally there has been no established procedure for testing and

maintaining equipment. In most cases testing and maintenance was

done only when a fault occurred. At a few stations where complete

routine checks were made, most potential failures were located and

corrected before an outage occurred.

With an occasional exception, maintenance appeared to be

better where it was assigned specifically to one or two persons.

Better records were kept and the individual peculiarities of the

system were more familiar to the maintenance personnel.
-9-

Maintenance personnel at Oceana have set up and maintained an excellent test procedure and a carefully kept set of records. Resistance of all circuits was measured daily with a low-voltage ohmmeter and recorded. When these measurements indicated any significant change in resistance, a "megger" measurement was made, and

plans for repairs could be made before a failure occurred. Thus

measurements were available for all seasons and weather conditions.

They have installed ammeters on each of the new type NC-3 regulators

to aid in daily checks. Since they had previously experienced

difficulty with all lamps in a circuit burning out after a certain

percentage of normal lamp failures, the ammeter checks are a valuable maintenance test. A higher than normal current is an indication that some of the lamps in that particular circuit have burned

out and that checks in the field are necessary.

Oceana has established a system of numbering each fixture and

component of all circuits. Individual records of each unit are kept by means of these numbers. All maintenance of each component

is recorded including lamp changes. Thus the records provide a detailed account of all operations.

With one exception, lamps were replaced as the burned out lamps

were noticed on a visual inspection. Patuxent River has been using

group lamp replacement for one runway and expects to extend this

method to the rest of the field in the immediate future. They reported that by using this method, frequency of visual inspection

was reduced and considerable saving in time for replacement was effected and work could be planned more efficiently since the time for

replacement can be estimated.

3.5 ADDITIONAL COMMENTS

3.5.1 Control Panels

Several tower operators were not satisfied with the type of

control panel in use. A panel simulating the field layout, sections

of which are automatically illuminated by the operation of the field

controls, was desired. If this was not possible, the installation

of pilot lights to indicate which runway- and approach-light circuits

are in operation was requested.
- 10-

At Atlantic City the control panel had been moved from the

console in front of the operator to a point about 10 feet away.

This is very unhandy, and the switch positions cannot now be seen from the tower operator’s position.

3.5.2 Taxiway Lighting Systems

Atlantic City in particular was not satisfied with the control system for the taxiway lights. To change the pattern on the

field it is necessary to turn off all taxiway lights before a sec- tion can be added or turned out. For stations like Atlantic City

which have both civilian and military traffic going to different

locations on the field, this is a serious problem, since all

traffic on the field must be stopped when a change is being made

or aircraft may run off of the taxiway during the period the lights are off, as has happened jOn occasions.

Ordinarily when several taxiway circuits are energized from

the same regulator, an open in one circuit will cause all the

lights to go out. To eliminate this, Quonset Point has installed

"Thyrite" cutouts across each circuit. These cutouts function on

an open series circuit by short circuiting the faulty circuit without affecting the others. This eliminates a series of checks by

the tower operators to determine the faulty circuit.

3.5.3 Miscellaneous

Only one station had radio communication between the control

tower and the airfield lighting maintenance vehicle. Nearly all

station maintenance personnel felt that radio communications would

expedite routine maintenance.

Personnel at some stations felt that the maintenance of airfield lighting equipment is considered of secondary importance;

that maintenance items were difficult to procure; and that time was not allowed for adequate preventive maintenance.

Personnel at several stations felt that the control circuits

should be protected by more than one main circuit breaker so that

a fault could not cause a complete blackout of all the visual

landing aids.
- 11 -

4. SUMMARY AND RECOMMENDATIONS

As a result of this survey some recommendations may be made

to improve maintenance and operation of the visual landing aids.

Some of these recommendations have general application, but many

of them have special applications to problems similar to those

encountered at a given station. After a good procedure for maintenance is eatablished, many of the airfield lighting problems

that arise may be solved locally. In some cases replacement of

obsolete equipment is the only satisfactory answer; in other cases a good airfield lighting maintenance manual will be of con- siderable assistance. Recommendations as a result of the survey

are as follows.

4.1 MAINTENANCE PROCEDURES ^ND EQUIPMENT

4.1.1 Establishment of Regular Maintenance Test Procedures And

Records

Regular and frequent checks of circuit resistance should be

made, recorded, and kept available. Analyses of faults, other

pertinent information, and checks should be carefully studied and

recorded.

. > 4.1.2 Assignment of Full Time Personnel

One or two persons should be assigned full time for airfield

lighting maintenance. They should participate in the acceptance

testing and inspection of all airfield lighting installations at

their stations. All applicable technical information should be

supplied them and should be kept current; e.g., drawings, instruc

tions, technical orders, lists of standard stock items with stock

numbers, and descriptions of new developments in maintenance and

lighting equipment.

4.1.3 Recommended Maintenance and Test

Equipment

Radio communication between the maintenance vehicle and the

control tower is virtually a necessity. This communication equip

ment can be obtained by using locally modified surplus aircraft

radio communication equipment. In addition to the standard test

equipment such as voltmeter, clamp-on ammeter, ohmmeter, and

"megger” there should be available a high-voltage insulation
- 12-

tester similar to the Takk Insulation Tester and a cable-fault

locating detector similar to the OBB Equipment. Permanently installed ammeters for the measurement of the output current of

runway regulators should be included as part of the regulators.

4.2 CABLE AND CABLE CONNECTORS

In general the new 5000-volt, polychloroprene-jacketed cable,

connectors, and isolating transformers are satisfactory but they

should be checked after they have had more time in service.

In unusual cases where faults are confined to a small area

of an airfield and the cause of the faults cannot be determined,

it may be desirable to use duct or metallic-sheathed cable. With

properly designed duct, the effects of lightning, soil-chemical

action, and other causes of failure would probably be reduced. The

cost of installing duct will be expensive but in some instances it

may be more economical than maintenance of cables, especially when

the results of outages are considered. In some cases duct may be

desirable to reduce the damage resulting from digging and trenching.

With one exception the lead-sheathed type of cable still in use has deteriorated until it has become a major maintenance problem. Early replacement of this cable is indicated.

The protective caps used to protect the connectors during

shipment should be saved and reinstalled whenever a connection is

opened during maintenance.

4.3 RUNWAY AND TAXIWAY LIGHTING

4.3.1 Improvement of Water Removal from Semi-FWsh Lights

The AN-L-9 semi-flush lights continue to cause trouble from

water leaking into the fixtures and grounding the circuits. Improving the seals and gasketing or providing a more convenient

means of removing the water are generally unsatisfactory except as temporary measures. A possible means of ^.removing the water is to use compressed air to blow out the water. The use of isolating

transformers will prevent multiple grounds in the circuit due to

water in the units.
-13-

4.3.2

Prevention of Damage to Elevated Lights

The problem of the cones of type M-l lights being blown over by jet and propeller blasts requires a redesign of the cones or of

the mounting, since jet blast can collapse the cone if it is

bolted down. Taxiing aircraft and other vehicles frequently damage

lights, especially the type C-l lights. This damage may be re- duced by improving their identification by painting the area around

the fixture with yellow paint or by using other easily identified

objects and paint to mark the location. Adequate marking of each

fixture will help prevent damage by snow removal equipment.

4.3.3

Correction of Lamp Failures Due to High Current

Increasing current from type NC-3 regulators feeding circuits

with isolating transformers as lamps burn out can cause the rest of

the lamps in the circuit to burn out. Since this characteristic

appears to be inherent in the design of the regulators, care in

keeping lamps replaced is required to improve the current regulation.

4.3.4

Group Lamp Replacement

Group replacement will be especially helpful in preventing

excessive current from regulators with isolating transformers if

the lamps are replaced before too large a percentage has failed.

Also it will help in planning work and aid in reducing outages from

lamp burnouts. It may be desirable to provide elapsed time meters

to determine the length of time the lamps have burned on the 100%

setting.

Various methods of group replacement are possible, but probably total replacement at a fraction of rated life recommended by

lamp manufacturers will be satisfactory. For runway lights or lights at critical locations, it will probably be desirable to replace burnouts occurring before total replacement time.

Another satisfactory method for determining when to replafcet

all lamps is to replace individual burnouts until a given fraction

(say 10%) of the lamps of the circuit have been replaced and then

to replace all the lamps in the circuit.
-14-

4.3.5

Taxiway Lighting

A taxiway lighting intensity regulator appears necessary for

use with the type M-l taxiway lights to reduce glare on clear

dark nights. It is believed that a two-step system will be adequate. The taxiway controls should provide for instantaneous

changing of one or more circuits without affecting the others.

For the moderate expense involved, the installation of "Thyrite"

cutouts to eliminate the possibility of complete taxiway lighting

blackout due to an open circuit in one of the circuits appears

justified.

4.3.6

Intensity Setting

Where high intensity runway lights are installed, the control

tower operators haye a tendency to set the intensity too high for

existing conditions. To aid the tower operators in setting the

intensity of runway lights, the installation of a runway light

directed toward the control tower and connected so it will burn

when any runway equipped with high intensity lights is selected,

is recommended. This fixture should be located 1000 to 1200 feet

from the tower. This provides a check by the tower personnel of

the appearance of the lights.

4.3.7

Indication of Runway- and Approach-Light Operation

A positive method of indicating to the tower operator the

satisfactory operation of all sections of approach- and runwaylighting systems is needed, particularly for the runways two miles

long and longer, now being constructed for operation of jet aircraft. This may be accomplished by a simple system of meters or of relays and pilot lights which indicate the nominal output

voltage of current regulators or the nominal output current of

voltage regulators.

4.4 GENERAL

4.4.1 Provision for Emergency Escape from U-Shaped Vault

Due to the possibility that a person can be trapped in the back

of the new U-shaped vault, some means of easy emergency escape should

be provided.
-15-

4.4.2 Additional Surveys

The above is based on information acquired from a limited

number of stations located near Washington. To determine if the

faults and maintenance problems found are common throughout all

Navy and Marine Corps stations, surveys covering groups of stations more remote from Washington are recommended.

4.4.3 Higher Echelon Inspection of Visual Landing Aids

In order to improve the efficiency of the operation and maintenance of visual landing aids, it is suggested that each' installation be visited at least once a year by a representative of a higher echelon. The visits should include conferences with the

station personnel who do the maintenance. During these visits

the maintenance records of the visual landing aids could be

checked and failures in cable and equipment noted. If the visits

are made by personnel of the District level, an annual conference

between them and personnel of the Bureau level would be helpful.

Adoption of such a policy should improve the morale of the maintenance men, promote a more rapid interchange of information at

all levels, and bring knowledge of common igaintenance problems,

equipment failures, and requirements promptly to the attention of

those concerned with evaluation and remedial action.
-16-

Appendix I

Survey Questionnaire

National Bureau of Standards

Visual Landing Aids Survey

Conducted for

Visual Landing Aids Section

Code AE-10, Bureau of Aeronautics

Station Date

Location

1. Number of Runways

2. Type of Runway Lights

Runway Runway

Runway Runway

Runway Runway

3. Total Number of Runway Lights

4. Types of Taxiway Lights

5. Number of Taxiway Light Circuits

6. Total Number of Taxiway Lights

7. Approach Lights Yes No

8. Approach Lights on Runways

9. Type of Cable

A. In Ducts Yes No

B. Total Length of Cable (Estimate)

C. When Installed

10 Isolating Transformers Yes No
-17-

11. Types of Cable Faults

A. Splices C.

B. Connectors D.

12. Type of Soil

13. Frequency of Cable Faults (All Bunways & Taxiways)

A, Particular Runway C. Circuit

B. Taxi way D„ Section

Types of Fault -Locating Equipment

A.

B.C.

D.

E.

F.

15.

Test Equipment Other Than Fault- Locating

A.

B.C.

D.

E.

F.

G.

H.

16. Regularity of Resistance Measurements

Annually Semi-annually

Monthly When Fault Occurs

17. Type of Records Kept of Measurements

Record Book Record Cards (Biddle)

Other

Quarterly

No

Mental

None
-18-

I

18. Availability of Records. Readily Other (Explain)

19. Record of Location of Faults Record Book

Field Plan Mentally None

20. Field Plan of Cable Location Available to Maintenance Personnel:

Readily Other (Explain)

21. Method Used to Determine Location of Cable Fault (Explain Fully)

22.

Is this Method Easily Adaptable to Other Stations?

Yes No

23.

Probable Cause of Most Cable Faults in Relation to Frequency of

Occurrence

Faulty Installation

A.

B.

C.

Digging and Trenching in Cable Areas

Faulty Cable (Explain Fully)

Termites Rodents

Lightning Soil Chemical Action

Other (Explain)

24. Method of Repair; Splice in Short Sections, . Replace Cable

Between Lights, Handholes, Manholes^ ' Other

25. Relamping Frequency

26. Group Relamping Yes No

27. Frequency of Routine Maintenance of Equipment

28. Fixture Cleaning

(
-19-

29. Alignment (End of Runway Lights)

30. Maintenance Personnel: Assigned as Needed

Total Assignment Number of Men

Part Assignment with Other Duties

31. Items of Equipment that Require Most Maintenance in Order of

Number of Faults and Probable Remedial Action to Minimize Fault

A.

B.

C.

D.

E.

32. Substandard Equipment Noted

33. Does System Meet Current Requirements?

34. Do Runway and Taxiway Markings Conform to ANC-1100?

Yes No

A. Turn-offs Indicated Yes No

B. Special Runway Marking

C. Destination Markers Yes No

1. Illuminated Yes No

35. Special Features in Use Adaptable to Other Stations

36. Additional Remarks
-20- I

Appendix II

Summary of Replies to Survey Questionnaire

The following is a summary of the answers to the Visual Landing Aids Survey questionnaire questions of Appendix I. For

questions with many different answers or opinions only the more frequent or characteristic answers are included.

Station Surveyed Location Date

Naval Air Station Atlantic City, N.J. 5-7-53

Naval Air Station Brunswick, Maine 5-4-53

Marine CorpsAir Station Cherry Point, N.C. 4-22,23-53

Naval Auxiliary Air Chincoteague, Va. 4-24-53

Station

Naval Air Station Johnsville, Pa. 5-6-53

Naval Air Station Norfolk, Va. 4-20-53

Naval Air Station Oceana, Va. 4-21-53

Naval Air Station Patuxent River, Md. 5-11-53

Marine Corps/ Air .’Station Quantico, Va. 4-30-53

Naval Air Station Quonset Point, R.I. 5-5-53

Naval Air Station, Washington, D.C. 5-1-53

Anacostia

1. Number of Runways: 37

2. Type of Runway Lights:

AN-L-9 at eight stations

C-l at five stations

M-l at seven stations

M-2 at three stations

3. Total Number of Runway Lights:

AN-L-9 845

C-l 712

M-l 867

M-2 285

Total 2709

4.

Types of Taxiway Lights: AN-L-9 and M-l

5. Number of Taxiway Light Circuits:

6. Total Number of Taxiway Lights:

74 plus 13 more in future

2857
-21 -

7. Approach Lights: Yes: One station plus one for near future

No: 10

8. Approach Lights on 1 Runway of 74 runways (ends).

9. Type of Cable:

3000-volt lead-covered (VCLC) at six stations

3000-volt polychloroprene at six stations

5000-volt polychloroprene at nine stations

9A. In Ducts:

Paved areas only at eight stations

Paved areas and one or more runways at three stations

Taxiways and other areas at no stations

9B. Total Length of Cable (Estimate): 3,185,000 feet

9C. When Installed:

Most of installation 1945 or before at five stations

Part of installation 1946 - 1950 at four stations

Part or all of installation since 1950 at six stations

Replacement of early installation planned or being made

at time of survey at three stations

. Average installation six years old

10, Isolating Transformers: Yes: No:

No isolating transformers at two stations

All isolating transformers at two stations

Part of installation has isolating transformers at seven stations

11. Types of Cable Faults:

Installation faults at three stations

Lightning damage at three stations

Faulty splices at three stations

Soil-chemical action on lead-sheath at two stations

Old 3000-volt, lead-sheath cable bad at one station

3000-volt, polychloroprene cable bad at one station

Rock punctures from ground movement at one station
«

-22-

12. Type of Soil:

Soil analysis not available. About one-half of the stations

are primarily hydraulic fill and the others are soil from

the local area.

13. Frequency of Cable Faults (All Runways and Taxiways)

:

None at two stations

Less than one per year at one station

One per year at two stations

Two to three per year at two stations

One per month at two stations

Two per month at One station

One per week at one station

Average: About ten faults per year per station

13D. Section: One station reports frequency of faults to be chiefly

l z "1l, jP local i zed to., one general area Two stations report one runway with old cable bad

j 14. Types of Fault-Locating Equipment:

Model OBB Cable Detecting Equipment at two stations

Stewart Type L Cable Tester at two stations, but results

unsatisfactory

None at eight stations

15. Test Equipment Other than Fault- Locating

:

Ammeters and voltmeters at eleven stations

"Megger" (500 to 2500 vdc ) at ten stations

Ohmmeter at ten stations

Recording ammeter and voltmeter at one station

Fisher M Scope on order at one station

16. Regularity of Resistance Measurements:

When fault occurs at six stations

Daily at one station

Monthly at one station

Annually at one station

No schedule yet at one station

No measurements at one station (at the station with the most

frequent occurrence of faults)

<
-23-

17. Type of Records Kept of Measurements:

None at nine stations

Record book at two stations

18. Availability of Records:

Readily available at three stations

No records kept at eight stations

19. Record of Location of Faults:

Record book at three stations

Mentally at three stations

None at three stations

Plans in office at two stations

New installation at one station

20. Field Plan of Cable Location Available to Maintenance Personnel:

Readily available at eight stations

Readily available but not complete at one station

Readily available on recent installations but very sketchy on original installations at one station

Complete plans, etc., of new installations available, but

no plans &f old system were available at one station

21. Method Used to Determine Location of Cable Fault:

OBB Cable Detecting Equipment primarily at two stations

Stewart Type L Cable Tester with modified pickup coil, but

not very successfully at one station

Sectionalizing and M cut and try" methods at eleven stations

22. Is This Method Easily Adaptable to Other Stations?

Model OBB Cable Detecting Equipment, with some practice, yes

Sectionalizing and "cut and try" method, yes

Modified Stewart Cable Tester, no

23. Probable Cause of Most Cable Faults in Relation to Frequency of

Occurrence

Digging and trenching in cable areas reported at six stations

Faulty installation reported at four stations

Lightning reported at four stations
-24-

t

23. Probable Cause of Most Cable Faults in Relation to Frequency of

Occurrence (cont.):

Faulty splices (primarily in lead-sheath cable) reported at

three stations

Old cable bad (primarily in lead-sheath cable) reported at

three stations

Soil-chemical action on lead-sheath cable reported at three

stations

Ground movement causing rock punctures reported at one station

Many other faults have no determined causes

24. Method of Repair:

Splice in short sections especially in feeders at nine

stations

Replace cable between lights at six stations

Replace cable between manholes or handholes at five stations

Splice in short sections in all cases except in duct at four

stations

25. Relaraping Frequency:

Daily as needed at nine stations

Weekly as needed at two stations

26. Group Relamping:

None at ten stations, but all were favorable to using it in

the future

On one runway and will use it on new installation when com- pleted at one station

27. Frequency of Routine Maintenance of Equipment:

Continuous at one station

Visual check weekly at one station

Visual check semi-weekly at one station

Visual check daily at five stations

Visual and meter checks daily at one station

Visual check daily with annual check with meters at one station

No set routine, as needed when fault occurs, at one station

<
-25-

28. Fixture Cleaning:

"As needed** at eleven stations

During daily checks at three stations (if lamp was replaced)

With lamp replacements at two stations which did not replace

lamps during daily checks

29. Alignment (End of Runway Lights)

Correct at eight stations

Incorrect at three stations, but correction was made during

the visit

30. Maintenance Personnel: Assignment:

One to three men on total assignment at six stations

Two and three men on part assignment with other duties at

two stations

Men assigned only as needed at three stations

31. Items of Equipment that Require Most Maintenance in Order of

Number of Faults and Probable Remedial Action to Minimize Fault:

Water in bases of type AN-L-9 lights at four stations

Runway lights damaged by jet and propeller blast and’ by. ground

traffic at three stations

Old 3000-volt cable is bad at three stations

Corrosion of contacts of AN-L-9 light fixtures at two

stations

High output current of 15-kilowatt Hevi Duty regulators with

isolating transformers at two stations

Old telephone-type control panel at one station

Snow removal equipment damaging fixtures at one station

Polychloroprene-type cable bad at one station

Female connector fills with dirt during repairs at one station

Brightness selector switch jumps stop at one station

Taxiway control panel is in wrong location and switching circuits are unsatisfactory as all circuits must be turned off

before making a change at one station

32. Substandard Equipment Noted:

Obsolete telephone-type control panels at two stations

Experimental design control panel at one station
-26-

i

33. Does System Meet Current Requirements?

Requirements met at eleven stations (when two installations

are completed)

34, Do Runway and Taxiway Markings Conform to ANC-1100?

Yes, at ten stations

No, at one station, but new markings under contract

344. Turn-offs Indicated;

Indicated at ten stations

Not indicated at one station, but indicator lights are being

installed

34B. Special Runway Markings;

None, except carrier decks at two stations

34C. Destination Markers;

Illuminated markers at one station

No destination markers at ten stations

35, Special Features in Dse Adaptable to Other Stations;

One station had a large sign near touchdown point reading

"WHEELS'* as a reminder to pilots

One station had installed wind socks near touchdown point

beside each runway

One station had installed G. E. Thyrite units in each taxiway light feeder circuit so that in case of an open

circuit the Thyrite will function, thus preventing all

lights going out due to a fault in one circuit

One station had installed ammeters in each 15-kilowatt

Hevi Duty regulator to read the output current and provide an easy means of determining if the output current was increasing due to some lamps being out.

One station had numbered each fixture and kept a complete

record of lamp changes, etc,, by fixture number

36. Additional Remarks;

Tower operators are setting high} intensity runway lights at

too high intensity

Plan to install elapsed time meters on brightness step 5 for

runway lights
-27-

36. Additional Remarks (cont.):

Type M-l taxiway lights are too bright for dark nights

Desire indicator in tower to show circuit failures

Voltage varies 10% daily plus 10% seasonally

Feel need for emergency exit in rear of U-shaped vaults

Feeling that airfield lighting is considered secondary

Experience difficulty in obtaining equipment from stock for

maintenance

Airfield lighting maintenance needs radio communications to

tower

(Remarks are covered more completely in the reports

)
'(it
THE NATIONAL BUREAU OF STANDARDS

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