GreaserMeter uses the iPhone accelerometer to measure how hard pilots are landing their aircraft in g. The device relies on measuring iPhone acceleration and needs to be secured to the aircraft structure in any orientation. Once secured to aircraft, it requires no further input. GreaserMeter uses input data from all three iPhone accelerometers.
It is essential that the iPhone does not enter the auto-lock mode as this will inhibit recording acceleration data and the app will not work. Ensure iPhone is set to Settings -> General -> Auto-Lock -> Never.
The app operates two modes, Airborne and Landed. The app is designed to be turned on at the top of descent. At this stage it will be in the Airborne mode. The app can recognise when the aircraft has landed and the status will change to Landed. A graph is then displayed showing the four seconds up to and including landing. This data can then be reviewed and will require some interpretation to identify which value relates to the touchdown. The highest g value recorded and time is displayed above the graph. The graph highlights in red where 2.1g has been exceeded. This is the threshold for a hard landing on the B737-800. A hard landing could require an inspection from engineers.
GreaserMeter is designed to work on commercial jet transport aircraft and would not work on turboprop or piston aircraft. It is designed to work on the B737-800, but is undergoing evaluation for other aircraft types. Refer to www.GreaserMeter.com to see which aircraft types it works on.
GreaserMeter will occasionally mistake turbulence and aircraft configuration changes for the landing and the status will prematurely change from Airborne to Landed.
GreaserMeter is not the definitive source for measuring how hard a landing is and is for advisory information only. As always, follow airline procedure.