products
Threshold and Runway End Lights Inspection by Drone
Drone inspection of runway threshold and end lights. Every unit in each bar counted, its colour checked and each bar scored against its serviceability…
OCT 12 2026
12 MIN
RUNWAY LIGHTING SYSTEM · EASA ADR.OPS.C.015
Runway threshold identification lights, both units of the pair
Two flashing white lights, one either side of the threshold, are what tells a crew where a hard-to-see threshold is. We capture the pair from the approach and record each unit: whether it fires, its flash rate, its colour, its output, its surveyed position and its place against the threshold, then report the pair with the threshold bar it belongs to.
Counts illustrative · generic airport · time compressed
2 units
one either side of the threshold, each with a record
per unit
firing or dark, and its colour
per pair
verdict, both units present and where the layout puts them
RTK ±1 cm
position of each unit
FROM THE FIELD
Real captures from real inspections
Every picture below comes from an inspection we flew: drone frames, field photos and app screens. The brackets mark what the analysis reads.
Threshold bars, the runway edge and a mast
4K frame from a PAPI flight on 9 Sep 2026, downscaled to 2880 px.
Green pair at the end of a light row
4K frame from the 18 Sep 2026 night session, cropped to the lit area at 100 %, brightness lifted slightly (gamma 0.8). Brackets on detected lights.
FIT
Who this is for
This service is bought by the person who signs the threshold identification row of the visual aids protocol. It fits the electrical manager at an aerodrome with a displaced threshold or a non-precision runway, the operator who has moved a threshold or replaced the flashing units and needs to show both are in place and firing, and the aerodrome with a periodic protocol due that wants the pair checked on the same visit as the threshold and runway end bars.
For
Airfield electrical and maintenance managers at aerodromes with a displaced threshold or a non-precision runway, where the identification lights are what makes the threshold readable and a night walk only shows whether they are on.
Operators who have moved a threshold, relocated the pair or replaced the flashing units and need a measured record that both units are where the survey puts them and firing.
Aerodromes that owe their authority a periodic visual aids protocol with a row for the threshold identification lights alongside the threshold and runway end bars.
Not for
Certified absolute photometry of a flashing unit, which is done with a calibrated instrument at the fixture rather than from the air.
Electrical faults in the flashing units' power supply, controller or cabling, which the protocol can point to through the unit that misbehaves but does not diagnose.
Deciding whether the runway may stay in a given operating category, which is the operator's call made from the findings the protocol gives.
JUDGED ON DELIVERY
Outcomes and acceptance criteria
Three outcomes are what the service is judged on, and each has a state you can check on delivery rather than a promise you have to trust.
01
A record for each unit
Each of the two units comes back firing or dark, with its colour and its surveyed position, and with its place against the threshold line and the edge lights it sits outside of.
Acceptance
Pick either unit, and its verdict, its position and the frames they came from are there.
02
A verdict for the pair
The pair is judged as the signal a crew reads: both units present, both firing and both at the threshold the layout gives. A pair with one unit dark or out of place is named as a failed pair at its position.
Acceptance
The pair has its verdict, and the unit that failed it is named with the reason.
03
A protocol the authority recognises as evidence
The threshold identification row of the visual aids protocol in ICAO, EASA or FAA wording, with the flight record and the source frames attached to every finding.
Acceptance
The document files as the periodic check without being retyped into another form.
What the service does not undertake to produce is a diagnosis of the flashing units’ power supply or controller, or a decision about the operating category. A unit that does not fire is named, and why it does not is the electrician’s question. The pair is captured on the same observation as the threshold and runway end lights
, and the runway edge lights
inspection covers the row running away from it in the same passes.
Seen from the approach, fixed from above
The pair exists to be seen from one direction, and the inspection looks at it from there and then fixes each unit against the survey.
An observation from the approach
The pair is unidirectional and shows toward the aircraft on approach, so an observation point out on the approach, at the height a crew sees the threshold from, is where it is judged. From there both units are in frame with the threshold bar between them, which is how the pair is read as a signal rather than as two separate lights. A fly-over then crosses each unit above its fixture, so its position is fixed against the survey.
Each unit, and then the pair
Each unit is tracked through the footage and scored on its own: firing or dark, its flash rate, its colour against the white it should show, its output and its surveyed position against the threshold line. The two records are then set side by side, so the flash timing and the output of the two units are compared, and the pair gets a verdict of its own. A unit that is missing, dark or at the wrong threshold is reported at its surveyed position, and the pair is reported as failed with that unit named.
VERIFIED PARAMETERS
What the protocol answers
The threshold identification row of the visual aids protocol, each item with the figure it is judged against.
11 parameters
EASA ADR.OPS.C.015
Parameter
What is verified
Tolerance
01
Pair configuration
One unit either side of the threshold, symmetrical about the centre line, in line with the threshold and outside the edge lights, each at its surveyed position.
Tolerance
Per CS-ADR-DSN
02
Colour
Each unit shows white, with no filter missing, damaged or discoloured.
Tolerance
Per CS-ADR-DSN
03
Firing
Each unit is seen to fire in the footage taken from the approach.
Tolerance
Both units firing
04
Flash rate
Each unit flashes white at a rate of 60 to 120 flashes per minute, read from the footage taken from the approach.
Tolerance
60 to 120 / min · Annex 14 5.3.8.3
05
Synchronisation
Whether the two units flash together is reported.
Tolerance
Reported
06
Relative output
The output of the two units is read against each other, so a unit that is lit but weaker than its partner is named.
Tolerance
Symmetric across units
07
Direction
The pair is visible from the approach side of the threshold, where it is meant to be seen.
Tolerance
Per CS-ADR-DSN
08
Unserviceable light
A unit that does not fire, or whose filter is missing, damaged or the wrong colour, is counted as unserviceable.
Tolerance
ADR.OPS.C.015(c)
09
Serviceability
The pair reported as present and firing or not. ADR.OPS.C.015(b) gives this system no separate percentage, and the protocol is issued against your authority's figure where one exists.
Tolerance
Per your authority
10
Threshold agreement
The pair sits at the threshold the surveyed layout gives, and not at the runway end where the threshold is displaced.
Tolerance
Per surveyed layout
11
Position
Each unit sits at its surveyed position, and a dark or missing unit is reported against the unit it belongs to.
Tolerance
RTK ±1 cm
EU values from ADR.OPS.C.015 under Regulation (EU) No 139/2014 and CS-ADR-DSN Issue 7. Where your authority publishes its own values, those apply. Protocols are issued in your authority's format for ICAO, EASA or FAA.
DELIVERY · 6 STEPS
From surveyed pair to scored protocol
01
Scoping call
You name the thresholds with identification lights, whether each is displaced, whether the threshold and runway end bars are in scope on the same observation and whether a surveyed layout exists. We agree the protocol template your authority wants. Output is a scope note. If the layout does not exist, the first visit produces it.
02
Mission build
The observation point on the approach and the fly-over across each unit are generated from the unit positions and the camera optics, so both units are framed with the threshold bar between them. Output is a validated mission and a capture window request to your tower, plus a request to your lighting control room for the pair to be on.
03
Capture
Flown between aircraft movements, usually on the same observation as the threshold bar and in the same sortie as the edge row. If a movement interrupts the observation, it is repeated unchanged rather than stitched.
04
Measurement
Each unit is tracked through the footage and its state, colour, flash rate, output and position are extracted and set against the surveyed layout and the threshold line. The two records are then set side by side for the pair verdict, with the flash timing and the output of the two units compared. Frames the tracker is not confident about are held for review rather than dropped.
05
Protocol
The threshold identification row of the visual aids protocol is filled in your authority's wording, with a verdict per unit, a verdict for the pair and the position of any unit that failed. Delivered the same day, with the flight record and the source frames attached.
06
Delivery and walkthrough
We walk your electrical manager through any unit that did not fire or sat away from its position, and what the pair verdict rests on. Anything disputed is re-examined against the retained footage rather than re-flown.
Example of the per-unit output, shown here for threshold and runway end lights
EVIDENCE AND CAPABILITY
The claim worth checking is the pair at the right threshold
A threshold that is hard to pick out gets a pair of runway threshold identification lights , one flashing light either side of it outside the edge lights, showing white toward the approach. Annex 14 calls for them at a non-precision runway where the threshold needs more conspicuity, and recommends them where a displaced threshold has moved the landing point away from the runway end. The FAA fits the same pair as runway end identifier lights. Either way the signal is the pair, and the pair is what a crew looks for.
The inspection therefore records the two units and then the pair. Each unit is found at its surveyed position from RTK positioning , its state and colour are read from footage taken from the approach side, and it is set against the runway threshold line the layout gives. A unit that does not fire, that flashes outside the rate of 60 to 120 per minute or that shows something other than white is named with its position. The two units are also compared for flashing together and for relative output. The pair then gets a verdict of its own, because one flash on its own identifies nothing.
The threshold is the second thing worth checking. The pair is fitted because the threshold is where a crew would not expect it, and a threshold that has been moved since the lighting was surveyed leaves the pair bracketing the wrong line. The inspection follows the surveyed layout, so the first thing the protocol reports in that case is that the survey and the pavement disagree, with the positions that show it. The threshold lights are captured on the same observation, so the green bar and the pair are set against the same line.
The serviceability rules treat this system differently from the bars beside it. ADR.OPS.C.015 gives a percentage for the threshold, the runway end and the other runway systems and none for the identification lights, so the protocol reports the pair as present and firing or not, and the runway light serviceability limits guide sets out where the other systems’ figures come from. Whether the runway keeps its category with one unit dark is the operator’s decision, made from the positions and the frames the protocol gives rather than from an impression.
HOW THE PRICE IS BUILT
Four things move the quote
There is no published rate for this service, because one displaced threshold and four thresholds across two runways are different days of work off the same method. The quote gives your figure, and the pricing page describes the combined visit.
EUR
per aerodrome per visit
excl. VAT
EU
Checked 2026-10-18
Cost driver 01
Thresholds with a pair
Capture and processing scale with the number of thresholds. Two thresholds on one runway share the setup and the tower coordination.
Cost driver 02
Bars on the same observation
The threshold and runway end bars are in frame on the same observation, so measuring them together costs less than measuring either alone, and each is scoped as a line item.
Cost driver 03
Combined visit
Measuring the edge row, the approach lights and the PAPI in the same visit costs less than buying each separately, because the travel and the access are paid once.
Cost driver 04
Travel
Shows up as travel and not as a different inspection.
Tell us the aerodrome and the thresholds and you get a figure and a date back. The pricing page
sets out the shape of a visit that covers every light and every surface, which is the cheaper way to buy the lighting protocol as a whole.
EACH WITH AN OWNER
Risks and dependencies
Three things can stop or degrade an inspection, and each has an owner.
Owner · WEATHER
Visibility and wind
Fog, precipitation and wind above the drone's limit stop the capture. The mission is flown when the window opens rather than measured through the weather. This is the most common reason a date moves.
Owner · OPERATOR
Access and lighting control
The observation needs tower coordination, at most aerodromes an escort, and a control room that keeps the pair on while the drone is in position. All three sit with the aerodrome operator and are worth confirming before travel is booked.
Owner · BOTH, AT SCOPING
The layout and the threshold
Each unit is scored against its surveyed position and the pair against the threshold the layout gives. If the threshold has moved or the units were relocated since the layout was made, the scoring is against the wrong line, and the protocol says so. Both are agreed at scoping.
Accountability sits with TarmacView for the capture, the measurement and the protocol, and with the aerodrome operator for access, for the lighting control and for what is done with the findings. Nothing on this page is a compliance statement. Whether a given protocol satisfies a particular authority is a question for that authority.
Frequently Asked Questions
- What are runway threshold identification lights for?
- They make a threshold stand out where the rest of the lighting does not. Annex 14 calls for them at the threshold of a non-precision approach runway when more conspicuity is needed or other runway lights cannot be provided, and recommends them where a threshold is displaced from the runway end. They are a pair of flashing white lights, one either side of the threshold outside the edge lights, seen from the approach. In the United States the same pair is the runway end identifier lights, REIL.
- Why is the pair reported, not just the two units?
- Because the pair is the signal. A crew on the approach reads two flashes bracketing the threshold, and one flash on its own does not say where the threshold is. So each unit comes back with its own record, firing or dark, its flash rate, its colour, its output and its surveyed position, and the pair comes back with a verdict of its own: both units present, both firing, flashing together and where the layout puts them. A pair with one unit dark is named as a pair that has failed, not as a system at half strength.
- Do you check that the pair sits at the displaced threshold?
- Yes. A displaced threshold is the usual reason the pair is fitted, and it moves the threshold away from the runway end. The inspection follows the surveyed layout, so each unit is found at its surveyed position and reported against the threshold it belongs to rather than against the runway end. If the threshold has moved since the layout was made, the first thing the protocol reports is that the survey and the pavement disagree.
- Is the runway closed for the inspection?
- No. The observation is made between aircraft movements in coordination with the tower, from the approach side of the threshold, and the drone clears the strip when asked. A pair takes minutes to capture and is usually taken on the same observation as the threshold bar. The lights have to be on while the drone is in position, which is a request to your lighting control room rather than to the tower. Processing and the protocol happen afterwards, off site.
- What is the serviceability limit for these lights?
- ADR.OPS.C.015 sets its percentages per system for the approach, threshold, edge, centre line, touchdown zone and runway end lights, and gives no separate percentage for the threshold identification lights. The protocol therefore reports the pair as present and firing or not, with the position of each unit, and leaves the operating consequence to the operator and the authority. Where your authority publishes a figure of its own for this system, the protocol is issued against it.
- Can it be combined with the other runway lights?
- That is the usual way to buy it. The pair sits beside the threshold bar and is in frame on the same observation from the approach, and the edge row, the runway end bar, the approach lights and the PAPI are measured in the same visit. Measuring them in one visit costs less than buying each separately, because the travel, the setup and the tower coordination are paid once.
References
- easa-ear-aerodromes
- Easy Access Rules for Aerodromes (Regulation (EU) No 139/2014), including CS-ADR-DSN Issue 7 European Union Aviation Safety Agency
- icao-annex-14-v1
- Annex 14 to the Convention on International Civil Aviation, Volume I: Aerodrome Design and Operations International Civil Aviation Organization
- faa-ac-150-5340-30
- AC 150/5340-30, Design and Installation Details for Airport Visual Aids Federal Aviation Administration
- tarmacview-pricing
- Pricing: one visit, every light and every surface TarmacView
Reviewed by Štefan Moravík · 2026-10-18
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Get Started
Get a scope note and a price within two working days
Send the aerodrome, the thresholds with identification lights and whether the runway lighting has a surveyed layout. That is enough to scope. You get a written scope note and a price back within two working days, and the scope note is not binding until you accept it.