Who Can Carry Out an Aerodrome Obstacle Survey?

The short answer

The aerodrome operator decides who does the survey but stays responsible for the data. A contractor can carry out the work if it is itself certified or works under the operator’s approval and oversight, with a formal arrangement that sets the quality requirement. The EU rules name no licence or profession for the surveyor.

Under the EU aerodrome rules the aerodrome operator is accountable for monitoring the obstacle environment and for the quality of the aerodrome data it supplies, and the fieldwork can be done by someone else. A contractor may carry out the survey if the operator keeps it under its approval and oversight (or the contractor is itself certified), has formal arrangements that set the quality requirement for each data item, and can show the data conforms. The acceptable means of compliance add a written agreement and a prior audit. The EASA text we read names no licence, profession or accreditation for the surveyor. It names a quality chain instead. National law can add requirements the EASA text does not, and we have not checked each state, so your competent authority has the last word.

That is the honest shape of the answer. The rest of this post sets out where each part comes from and what it does not say.

The operator owns the question

Point ADR.OPS.B.075 of Regulation (EU) No 139/2014 is a rule, not guidance. It requires the aerodrome operator to monitor the aerodrome and its surroundings for the obstacle limitation and protection surfaces set by its certification basis, for the marking and lighting of obstacles, and for hazards from human activities and land use. It also requires procedures for mitigating the risks.

The acceptable means of compliance beside it adds two points. The scope, limits, tasks and responsibilities of the monitoring are defined in coordination with the competent authority and the air traffic services provider. And the monitored area should include what can be seen during inspections of the manoeuvring area.

Contracting does not move the accountability. ADR.OR.D.010 lets an operator contract activities, and its guidance lists “surveying for aeronautical data” as an example. The guidance adds that the ultimate responsibility for the product or service always remains with the aerodrome operator. A survey company supplies measurements. It does not take over the duty. This matters for aerodrome certification , because the certificate holder answers for the data whoever collected it.

Two jobs that get confused

People say “obstacle survey” for two different jobs. They carry different weight.

Monitoring is the operator’s continuing task. Annex 14 section 2.5.5 and its EU counterpart cover data that ends up with the aeronautical information service , and from there into publications such as the AIP . The Annex states that coordinates of obstacles in Area 2 (the part within the aerodrome boundary) and in Area 3 are measured and reported in degrees, minutes, seconds and tenths of seconds. The top elevation, type, marking and lighting are reported too. The Annex points to PANS-AIM Appendix 8 for how obstacle data is determined in those areas, and that document is paywalled, so we describe it no further.

A drone flight that finds a tree has grown into a surface is monitoring. A set of coordinates that goes to the information service is data origination. The second faces the quality chain. The first is the operator’s own procedure.

Who can hold the survey pen

For data that leaves the aerodrome, three provisions work together.

First, ADR.OR.D.010 says a contracted organisation is either itself certified to carry out the activity or, if not certified, works under the operator’s approval and oversight. In that second case the operator also has to give the competent authority access to the contractor. The AMC adds a written agreement and a prior audit of the contracted party, so the operator knows it has the resources and competence for the task.

Second, ADR.OPS.A.010 requires formal arrangements with the organisations the operator exchanges aeronautical data with. The AMC names “services for the origination and provision of survey data” and “electronic obstacle data” among them. Its minimum content includes:

• the data to be provided and the quality requirement for each item
• the method for showing the data conforms
• the action to take when an error is found
• the party responsible for documenting changes
• limits on the use of the data
• origination quality reports and metadata

Third, the guidance to A.010 sends contracted origination to ATM/ANS.OR.085 of Annex III of Regulation (EU) 2017/373. We did not open that regulation for this page, so we cannot say what it demands of a survey company beyond that pointer.

The UK: CAA guidance CAP 1732

In the UK, the CAA’s Aerodrome Survey Guidance, CAP 1732, applies to aerodromes certificated by the CAA under Regulation 139/2014 and to aerodromes with instrument flight procedures. Other aerodromes stay with the older CAP 232. It repeats the EU position. Contracted data origination works under the operator’s oversight, the operator needs a formal arrangement with the surveying organisation, and ultimate responsibility for the data always remains with the operator.

The guidance says that arrangement should state which data files the surveyor delivers and whether the operator nominates the surveyor as an AIP Sponsor for that data. It asks for coordinates in WGS-84 and makes the data originator responsible for the accuracy of the control data and any transformation sets. We found no licence or accreditation for surveyors in it.

Chapter 4 covers the monitoring job. Operators are required to have procedures for continuous monitoring of the obstacle environment, and should review their survey data and obstacle-data activities every year. The edition we read is Edition 1 of December 2018. Check the CAA site for the current one.

What the rules ask you to be able to show

The EASA text sets no list of approved surveyors. It sets out what the operator has to document and control.

• The aerodrome manual. The structure in the AMC3 for ADR.OR.E.005 includes “procedures and frequencies for aeronautical data surveying, including areas to be surveyed”.
• Metadata. ADR.OPS.A.045 requires a record of who performed each action on the data, what the action was and when.
• Checking. ADR.OPS.A.035 requires data entered manually to be independently verified.
• Tools. ADR.OPS.A.055 requires the software used in the data process not to degrade the data. Whether software that turns survey imagery into coordinates counts as a tool in that process is for your authority to say.

The accuracy figures themselves sit in the aeronautical data catalogue and in PANS-AIM, which we have not reproduced. Take them from your arrangement, not from a blog.

The United States

The FAA route is different in form. AC 150/5300-13B is voluntary guidance except for projects funded under certain federal grant programmes, such as the Airport Improvement Program, and for projects funded by the Passenger Facility Charge program (its paragraph 3). Its paragraph 3.4.8 says to perform surveys in accordance with ACs 150/5300-16, 150/5300-17 and 150/5300-18, and paragraph 3.4.4 says an obstruction survey identifies objects that may affect aircraft operations in the approach and departure path. We did not open those three circulars, so we do not state who may perform the work under them.

Where a drone fits, and where we stand

None of the texts we read names an instrument. A drone can support the monitoring job, finding change where a register is old. Whether drone-derived coordinates can serve as originated data depends on whether the chain above can be shown for them, which is an argument for your authority to accept. In the UK, a drone flight inside an aerodrome’s flight restriction zone also needs permission from the site, given by air traffic control or the aerodrome operator.

Our OLS survey is in development and is not offered yet. What exists today is a working record in which obstacles are entered, imported or seeded, each with a height above ground and its MSL and ellipsoid heights, MSL being an orthometric height . It is a working record for the operator, not an official obstacle register. It also warns when an obstacle penetrates the approach surface . It does not test the other obstacle limitation surfaces yet, and it is not a certified obstacle data set. Heights are only as good as their source. Where a decision turns on centimetres, a ground survey by a surveyor with survey-grade GPS remains the right next step. For the surfaces themselves, see Obstacle Limitation Surfaces: Surveying the Approach . For how acceptance works in general, see What a Regulator Actually Accepts as Evidence .

Questions to settle before you commission one

1. Which data items are being originated, and to what quality requirement for each?
2. Does the provider hold its own approval for the activity, or will it work under your approval and oversight?
3. How will conformity be shown, and who signs it?
4. What metadata travels with the data, and who verifies manual entries?
5. Where in your aerodrome manual are the survey method, interval and areas written?
6. Does national law in your state add a requirement for the surveyor?

The last question is the one only your authority can answer.