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Bowmonk Airfield Friction Meter

SBOW 009  Bowmonk AFM2 Mk3 is a compact, portable electronic instrument for measuring and recording the maximum deceleration possible on a airport runway or road surface. 

Advisory Circular 150/5200-30D [pdf]
(click above link to open)

Notification of Calibration and Re-Certification [pdf]
Authorization to Proceed with Calibration Form [pdf]

The Bowmonk Mark 3 is the modern day equivalent of a mechanical decelerometer such as the Bowmonk Brakemeter or Tapley Brake Meter.

It contains a solid state accelerometer and an accurate crystal controlled clock. During a friction test, the accelerometer measures the deceleration (g-force) experienced by the transporting vehicle, 400 times per second with an accuracy of better than 2%. The output is read by a microprocessor and stored in the 128k memory for automatic analysis at the end of the test.

In use the Bowmonk Mark 3 is simply positioned on the passenger seat or in the footwell of the vehicle- usually a good condition pick-up with balanced springing and good tires.

Control and setting of the Bowmonk Mark 3 is via a seven button keypad which provides for airport , runway, and operator identification.

The Bowmonk Mark 3 is fitted with a two line alphanumeric liquid crystal display. This is used to prompt the user for command entry via the keypad, to indicate results and to give any error messages. Night time operation is facilitated by back-lighting of the display panel.

The Bowmonk Mark 3 contains a miniature dot matrix impact printer capable of printing text in 40 columns and graphics of 240 dots per line. Printout of results is obtained by pressing the (P) in the memory and the printout will show individual friction readings, averages for each one third of the runway, and a total average of all friction readings taken. The printout will not fade and duplicate copies can be taken automatically.

The Bowmonk Mark 3 is powered by an internal rechargeable battery. When fully charged this will power the instrument for at least 12 hours testing and printing. The battery voltage and charge can be shown on the display.

The battery cannot be overcharged. However, if allowed to run down too far it can be difficult to recharge. We recommend, therefore, that after use the battery always be left on recharge.

* Records true vehicle deceleration
* Provides hard copy printouts of up to 99 friction tests together with calculated total runway average or thirds.
* Compensates for peaking due to initial vehicle pitching.
* Indicates friction values 10% below average and disregards tests cancelled by operator or considered faulty.
* Permits selection of airport, runway and operator through keypad or barcodes.
* No mounting kit or connections to the vehicle are required.

The AFM2 is ABS compatible, however, please refer to your local aviation authority for advice on its use with ABS enabled vehicles.  For example, the FAA allows portable electronic decelerometers like the AFM2 to be used with ABS-equipped vehicles (with no requirement to disable the ABS), as detailed in its Advisory Circular 150/5200-30D.

In October 2016 changes were made to the process of assessing and reporting airport runway conditions.  The FAA has confirmed that runway friction assessments should still be used, even though friction readings no longer need to be included with every Field Condition (FICON) report submitted to the NOTAM system. Click here for more information.

    Standard Features:
    • All stored results can be downloaded to a PC compatible computer via an RS 232 port.
    • Capability to Store 32 runway and 32 operator ID's to memory, retrievable at the keypad buttons.
    • Vehicle no longer requires a complete stop.
    • Recalibrated and serviced in the United States.
    • 32 character high contrast alpha-numeric liquid crystal display with back lighting for night-time visibility.
    • Tactile switches, with beep, for selection purposes.
    • Automatic cancellation of faulty friction tests.
    • Manual cancellation of faulty friction tests.
    • Provides for temporary suspension of friction testing with no loss of recorded data.
    • Stores up to 99 friction readings.
    • Provides each third of runway and operator identification.
    • Permits field programmable airport name, runways, and operators through keypad.
    • No mounting kit required.
    • 128k CMOS memory with battery backup.
    • No connection to vehicle necessary.
    • Built in 6 volt rechargeable battery (external voltage for battery recharge 9v to 18v DC) powers unit for at least 12 hours. Can be recharged from main power pack, vehicle power outlet or 120vAC or cell phone charger outlet.
    • Built in temperature compensated accelerometer records runway friction coefficient in compacted snow and ice conditions as %g.
    • If required, a graphical print-out of each friction test showing the variation in friction along the runway can be printed.


    • Measurement range 0 to 1.4g.
    • Size just 14 x 22 x 8cm. Weighs 2.75kg.
    • Clock battery life 5 years.
    • Operating temperature: 32 degrees Fahrenheit (0 degrees Celcius) to 104 degrees Fahrenheit (40 degrees Celcius).
    • Storage temperature: -4 degrees Fahrenheit (-20 degrees Celsius) to140 degrees Fahrenheit (60 degrees Celsius).

    Maintenance Requirements:

    • Replacement of battery.
    • Replacement of printer ribbon and paper.
    • To ensure accuracy of the Bowmonk AFM2, we recommend that an annual calibration and re-certification be completed by Bowmonk. It is recommended that the units be returned for calibration during the summer months.


    • An operator manual is provided- no special training is necessary.


    • No installation is required. Velcro backing will hold the AFM2 securely to the front seat or floor well.


    • Standard one year warranty.