Threshold Lighting
The threshold lights will divide a displaced threshold and the usable runway. All “A” series approach lights have threshold lights.
Centerline Lighting
Roll Bars
The centerline lights are useful for runway alignment but can be misleading absent any other cues. The roll bar provides the third dimension.
Sequenced Flashing Lights
Runway Alignment Indicator Lights (RAILS)
Side Row Bars
Termination Bars
If you are descending below 100 feet based on the approach lights, you must either see the red terminating bars or the side row lights. In other words, if you do not see either set of red lights you must see the runway itself.
500 Foot Roll Bars
Wing Bars
High Intensity ALS with Sequenced Flashers (ALSF-2)
At the 1,000 foot “Roll Bar” you are about 2,000 feet from touchdown, about a third of a mile. You should be about 100 feet AGL at this point.
The sequenced flashers begin between a half and three-quarters of a mile from touchdown. You should be about 300 feet AGL at this point.
Example: ELLX Rwy 06
ALS with Sequenced Flashers (ALSF-1)
Medium Intensity Approach Lighting System (MALS)
Medium Intensity Approach Lighting System (MALS)
At the 1,000 foot “Roll Bar” you are about 2,000 feet from touchdown, about a third of a mile. You should be about 100 feet AGL at this point.
Medium Intensity Approach Lighting System (MALS)
Example: KBED
Medium Intensity Approach Lighting System with Sequenced Flashers (MALSF)
At the 1,000 foot “Roll Bar” you are about 2,000 feet from touchdown, about a third of a mile. You should be about 100 feet AGL at this point.
Note: the Simplified Short Approach Lighting System with Sequenced Flashers (SSALF) appears identical to the MALSF.
Example: EICK
Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights (MALSR)
At the 1,000 foot “Roll Bar” you are about 2,000 feet from touchdown, about a third of a mile. You should be about 100 feet AGL at this point.
The sequenced flashers begin between a half and three-quarters of a mile from touchdown. You should be about 300 feet AGL at this point.
Note: the Simplified Short Approach Lighting System with Runway Alignment Indicator Lights (SSALR) appears identical to the MALSR. It is an older system used when category I conditions exist on category II designated runways with a dual mode approach lighting system (ALSF-2/SSALR).
Example: KTEB Rwy 06
Omnidirectional Approach Lighting System (ODALS)
Visual Approach Slope Indicator (VASI)
Pilot of high cockpit aircraft, the Boeing 747 for example, could touch down short of the runway if using standard 2-Bar VASI or the first two bars of a 3-Bar VASI. See Deck Angle for a discussion of the geometry behind this. High cockpit crews need only remember to use the far bars of a 3-Bar VASI and to ignore the first set of bars. Standard cockpit crews always use the first two set of bars.
Example: (Four box system, KSAV, Runway 19)
