On This Page
Define what the inspection must establish
Start with the component and the decision it supports. Photographing coating
breakdown on a handrail, investigating a thermal anomaly on equipment and
measuring remaining steel thickness are separate jobs. This distinction should
appear in the drone inspection scope of work before anyone selects an aircraft.
Use the following as a specification outline. The deliverables are recommended
contract inputs, not a claim that every supplier provides them.
Scroll horizontally to compare all columns.
Thermal cameras measure infrared radiation. FLIR explains that temperature
interpretation depends on emissivity, reflected radiation and the atmosphere
between the camera and target. Emissivity describes how effectively a surface
emits thermal radiation. Reflective metal can therefore give a misleading
apparent temperature unless the method accounts for its surroundings. Request
the underlying measurement files and assumptions, not only a colored screenshot.
See
FLIR's thermographic measurement guidance.
Ultrasonic thickness measurement introduces physical contact. Flyability's
UT Payload Quick Start Guide
describes probe contact, couplant, calibration and qualified interpretation.
Couplant helps transmit ultrasound between the probe and material. Surface
condition and probe stability matter, so a camera flight should never be sold as
thickness measurement by implication.
For process pipework, our explanation of visual, thermal and methane inspection
workflows helps separate another set of easily confused outputs. Choose the
measurement method for the question being asked.
Divide the installation into inspection areas with named components and required
viewing directions. Topside steelwork, the underside of a deck and a flare tip
present different routes and obstructions. Specify which faces matter and
identify where the crew will control the aircraft, maintain observation and
recover it.
Check the exact aircraft manual before assuming a vessel is an acceptable launch
point. DJI's current downloadable Matrice 350 RTK manual prohibits takeoff from
moving objects, including ships. That restriction is a concrete example of why
an industrial aircraft designation does not establish suitability for every
offshore deployment. It is not a restriction asserted for all drones. See the
Matrice 350 RTK user manual on DJI?s downloads page,
pages 14-15.
The same manual warns that steel structures can affect satellite positioning and
obstruct the video link. An underdeck plan should therefore explain the
positioning mode and control-link behavior in the actual geometry. Require the
operator to identify what happens if navigation assistance or the link degrades,
where the aircraft can retreat and which surfaces become unreachable. A general
radio-range figure does not answer those questions. Evaluate the planned route
with the configured payload and define a recovery reserve; a successful outbound
leg does not prove the aircraft can finish the inspection and return safely.
Before mobilization, request the current asset drawings, component numbering,
inspection history, access restrictions and operating schedule. Agree how
helicopter movements, crane work and process changes will be communicated to the
flight team. Our
refinery inspection planning guide
provides related process-site planning context; the offshore plan still needs
its own launch, recovery and access arrangements.
Treat a live flare as a separate task
A live-flare inspection can collect external observations without requiring
access to the tip. It does not establish that every requested defect can be seen
while the flare operates. The buyer should separate observations feasible during
operation from details requiring another angle, another method or a shutdown.
Engineers with Drones describes a site-specific stand-off assessment based on
flare type, thermal output, wind and stack configuration. Its stated method
excludes flight through or above the flame. That is useful evidence of how one
provider bounds the task, not a universal distance or a guarantee for another
installation. See its
flare inspection method.
Ask the provider to connect each required view to the allowed flight area. Which
side of the tip is visible? What happens when wind or flare operating conditions
change? Who supplies the process information, and who can stop the inspection?
If the desired detail cannot be resolved from the permitted position, record it
as incomplete rather than reducing stand-off to obtain a sharper image.
Heat exposure and explosive-atmosphere suitability are separate questions. HSE
identifies movable electrical equipment and radio-frequency radiation among
potential ignition sources in its
electrical and instrumentation guidance.
The Matrice 350 RTK manual also prohibits using that product in a potentially
explosive atmosphere. Site access permission must not be treated as overriding
an equipment restriction.
Have the installation's responsible personnel identify the applicable hazardous
areas and operating restrictions. Confirm the actual aircraft, battery, payload
and accessories against the intended environment. Do not assume that a
protective cage, an ingress rating or a thermal camera establishes explosion
protection.
Separate rain protection from marine suitability
A rain rating is only one input to an offshore equipment decision. DJI states
that the Matrice 350 RTK reaches IP55 under specified laboratory conditions with
TB65 batteries, and that protection can deteriorate with use. Its manual also
identifies conditions that invalidate that rating, including incorrectly fitted
port covers and aircraft damage. These conditions do not amount to a saltwater
qualification.
Ask for separate documentation covering the proposed salt exposure and the care
procedure for the complete configuration. Include the payload, connectors and
charging equipment. Where the manufacturer has not documented suitability, keep
that uncertainty in the equipment decision rather than converting an IP rating
into an assumed marine capability.
Plan a dry area for battery handling and equipment storage. The DJI user manual
calls for dry battery interfaces before insertion, liquid-free battery surfaces
and ports before charging, and removal of liquid before packing. Its
maintenance manual on the same downloads page
includes checks for corrosion at battery ports, lens cleanliness and clear
ventilation paths.
Specify who performs and records the post-flight inspection, what condition
removes equipment from service and how spares will be supplied offshore. Follow
the manufacturer's cleaning instructions for each component; do not prescribe a
general freshwater rinse for electronics. Ask the bidder to separate productive
inspection time from weather standby, equipment care and remobilization. Agree
who pays for a return visit when an excluded view later becomes necessary; a low
flight-day price can leave that work outside the quoted scope.
Specify a usable inspection handover
Before the first production flight, agree a sample deliverable with the person
who will use the results. A useful sample shows the component's location, a
detailed observation, its original file and the proposed next action. It should
also demonstrate that the recipient can open the files without depending on a
presentation video.
For a visual survey, request an asset-indexed image set and a coverage register.
Record required faces as inspected, partly inspected or not inspected, with
reasons for gaps. Define the detail the method must show using a representative
trial, with the intended viewing distance and operating conditions. Camera
resolution by itself is not an acceptance test for a particular defect. Keep
detection, identification and sizing as separate requirements: seeing an
indication does not establish its type or dimensions. Agree when uncertain
observations require a second method.
For thermal work, add the original radiometric files, matching visible views,
target identity, acquisition conditions and settings used in interpretation.
State whether the report offers qualitative anomaly screening or a temperature
measurement. Those outputs warrant different confidence and follow-up decisions.
For ultrasonic work, require the qualified procedure, calibration information,
measurement locations and retained signal records appropriate to the method.
HSE's April 2008 guidance on
ultrasonic sizing errors and defect assessment
distinguishes inspection data and its errors from the engineering assessment of
continued service. That document addresses defect sizing and explicitly excludes
wall-thickness measurement errors; it is not a validation of a drone thickness
system.
Agree how findings will enter the owner's maintenance system. Component names,
observation IDs and file references should remain consistent from capture to the
final report. Keep an observation separate from an interpretation and from the
resulting maintenance instruction. An inaccessible area should remain an open
inspection item, even when all other contracted flights are complete.
Ask bidders to explain the gaps
A useful proposal should answer five questions:
- Which component faces and defect types can the proposed method inspect, and
which are excluded?
- What evidence supports the aircraft's launch, recovery and environmental
suitability at this installation?
- How will live-flare conditions and process restrictions change coverage or
stop the work?
- What original files, measurement records and unresolved findings will the
owner receive?
- Who reviews the observations and decides whether another inspection method is
necessary?
Choose the proposal whose demonstrated outputs match the maintenance decision
and whose exclusions are explicit. If the task needs a contact measurement, a
closer view or an operating condition the aircraft cannot support, retain that
work in the wider inspection plan. The value of offshore drone inspection is a
usable, traceable contribution to asset assessment, with its limits visible to
the people making the decision.
Source notes
Last checked: September 10, 2026.
