diff --git a/src/platforms/posix/drivers/airspeedsim/airspeedsim.cpp b/src/platforms/posix/drivers/airspeedsim/airspeedsim.cpp
index ea9d92025e..5c2de4e3ce 100644
--- a/src/platforms/posix/drivers/airspeedsim/airspeedsim.cpp
+++ b/src/platforms/posix/drivers/airspeedsim/airspeedsim.cpp
@@ -211,7 +211,7 @@ Airspeed::ioctl(device::file_t *filp, int cmd, unsigned long arg)
 					bool want_start = (_measure_ticks == 0);
 
 					/* convert hz to tick interval via microseconds */
-					unsigned ticks = USEC2TICK(1000000 / arg);
+					long ticks = USEC2TICK(1000000 / arg);
 
 					/* check against maximum rate */
 					if (ticks < USEC2TICK(_conversion_interval))