Abstract: A client-server system and method for calculating whether time-crucial shipment is located according to expectation comprising a device and a remote special purpose computer, the device comprising a non-lithium battery; a Wi-Fi receiver; a GSM module; an accelerometer; a Wi-Fi antenna; a GSM antenna; and a microcontroller programmed to store identification data of each Wi-Fi access point within range and time each Wi-Fi access point was accessed, to automatically turn off the GSM module when aircraft engine vibration is detected; and to automatically transmit via GSM protocol the Wi-Fi access point data when aircraft engine vibration is no longer detected. The remote special purpose computer uses a flight plans database and a Wi-Fi access point database to calculate location of the device based on the Wi-Fi access point data received via GSM and compare the calculated location to an expected location based on a flight plan.