Airborne Methane Gas Detection


  • Gas wells, pipelines and processing plants may leak with time leading to the following:
  • Safety hazards
  • Substantial loss of income to gas company
  • Danger to environment
  • Adverse publicity
  • Potential loss of social license to exploit gas resource
  • Breach of Government Regulations

Ultramag is now offering, under exclusive rights, the Pergam ALMA G2 – a well proven, state of the art airborne Laser Diode methane gas (CH4) detection system. We measure CH4 concentration at ground level from an elevation between 50m and 200m above the target at up to 100 km/hr. Sensitivity is 20ppm * m @ 50m height and 40ppm * m @ 150m height.

We have the capacity to survey:

  • Line targets (pipelines)
  • Points (wells)
  • Polygonal areas via systematic grids (gas processing plant)
  • Detailing leaks in 2 dimensions (plan).
  • Gas leakage from surface and buried pipes

We also offer real-time warning (satellite phone) and reporting of all critical gas levels.
The CH4 detector and four video cameras are mounted on the underside of the helicopter facing downwards (above photo). A control unit and computer are mounted in the cockpit.


Safety is of paramount importance to Ultramag. We have over 25 years experience working in minerals and coal exploration including development of Intrinsically Safe equipment and working with helicopters.

The system is non-destructive and will not ignite a methane gas plume.
Flying 50m to 150m above a target is safer than on the ground or low level flight through plumes.

We only use suitably qualified operators and pilots.

Operating Principle

The detector pulses a laser beam at the target area. The laser is specifically tuned to 1.65 μm wavelength (near infra red) as the C-H bonds in methane absorb energy at this wavelength. The light is reflected off the target and light intensity is measured back at the detector by a photo detector and scaled to give methane concentration. Two algorithms are run on the data to extract a range of methane concentrations.

The laser is focused downwind of a target. As signals can change slightly with temperature, a methane gas standard is also sampled by the laser to calibrate the instrument on boot-up.

Surveying is a two person operation –pilot and qualified technician for safety and data quality control.

Our system is certified on a helicopter by helicopter basis to meet all Australian aviation standards. All pilots used are certified and experienced for low level flight.


Space delimited ASCII point located data for methane concentration including MGA coordinates, date and time stamp.

Color coded image of methane concentration overlaid on base maps (optional). Basemap formats:
Images from Google Earth Pro o Air photos (provided by client) o Scanned Topographic maps

Image output formats:

  • ERS
  • ECW
  • GeoTIF
  • JPG (not geo-coded)

Report including base plan, instrument specifications, hazard ID, location, time, date with supporting pilot camera photos.
Methane trigger thresholds to be specified by client. All data on DVD, hard disk or via secure web server.

ALMA G2 Specifications

  • Gas Detection Method : Laser Diode
  • Flight speed : 80 to 150km/hr (40 to 80kts)
  • Flight Height : 50m to 200m
  • Maximum detection range : 200m
  • Measurement Time (2 different algorithms) : 0.04s + 0.2s (simultaneous)
  • Relative measurement accuracy : 1%
  • Swath width mapped on ground : 7m
  • Operating Temperature : -10°C to +50°C
  • CH4 sensitivity : 20ppm *m (50m flight height) 100ppm *m (100m flight height)
  • Cross winds : Up to 65km/hr (35kts)
  • Maximum 45km/hr (25kts) recommended

Data acquisition

  • Typical survey rate Typical data density : 5 readings/second (large leaks) 40 readings/second (small leaks) 40km/hr – 80km/hr
  • 0.5m (small leaks @ 50km/hr)
  • 2.7m (large leaks @ 70km/hr)

Position control : GPS (see below)

  • Laser : Eye safe, 1.65μm wavelength.
  • Digital video cameras for flight line verification : 4 cameras to document 50m either side of flight line
  • Weight : 70kg + 10kg console
  • GPS Specifications (inbuilt) Position accuracy (x,y) Stand alone receiver, mobile 3m
  • Data Acquisition : 5Hz LASER cycle > 5Hz
  • Position interpolation : Datum GDA94 or re-projected as per specification

Quality Assurance

  • The system is self-calibrating.
  • A methane gas standard is contained within the detector and sampled on boot-up.
  • Four cameras track the laser path. One camera is mounted coaxially.
  • The system is not affected by water vapor, CO2 or ethane gas.
  • A range of GPS quality factors are stored with each position. Flight paths are overlaid on geo-coded base maps.
  • Clients are welcome to add blind methane sources for further QA.

Data Processing

  • Editing is undertaken using Ultramags proprietary XYZEDIT.
    ChrisDBF for gridding data.
  • ERMapper for image processing and final output. We can combine multiple layers of information with transparencies etc.., mosaic air photos etc…
  • MapInfo vector and image import/export.
  • AutoCAD vector import/export
  • Image processing can be undertaken same day on site if required as an additional service.

Data Turnaround

  • Emergency real-time reporting service via Satellite phone.
  • Final data 3 days, via secure Internet server with real-time emergency target reporting via Satellite phone.
  • Final report 2 weeks.