DD ENV 50235:1997

Contents
1. Scope, object and fundamental principles
2. Normative references
3. Definitions
3.1 ICAO
3.2 Taxiway (T 11)
3.3 Movement area (M 41)
3.4 Manoeuvring area (M 4)
3.5 Apron (A 119)
3.6 Taxiing guidance signs
3.7 Mandatory instruction sign
3.8 Information sign
3.9 Luminaire
3.10 Frangibility (F 36)
3.11 Rated current
3.12 Optical component
3.13 Routine test
3.14 MTBF - Mean time between failures
3.15 MRT - Mean repair time
3.16 Repair time
3.17 Useful life
4. Classification and designation
4.1 Classification according to service conditions
4.2 Classification according to operational use
4.3 Classification according to electrical supply
4.4 Markings
5. General requirements
5.1 Components of signs
5.2 Service conditions
6. Performance requirements
6.1 Photometric requirements
6.2 Electromagnetic compatibility
6.3 Dependability
6.4 Integrity
7. Design and construction
7.1 General requirements
7.2 Mechanical strength
7.3 Protection against electric shock
7.4 Protection against ingress of dust, solid objects
     and moisture
7.5 Insulation resistance and electric strength
7.6 External and internal wiring
7.7 Provision for earthing
7.8 Sign faces
7.9 Drain holes
7.10 Fastenings and covers
7.11 External finish
7.12 Replaceable components
7.13 Optical components and lampholders
7.14 Ballasts (or lamp control gear)
7.15 Electric converters
8. Tests
8.1 Type tests
8.2 Routine tests

Covers signs installed in the movement area to provide information to pilots and vehicle operators. Applies to signs with built-in illumination arrangements using tubular fluorescent, tungsten filament and other discharge lamps on supply voltages that do not exceed 1000 V.