After an extensive retrofit, three pilots board a modified cargo plane for a routine test flight that ends in disaster. The wreckage tells investigators the plane hit a Virginia mountainside in one piece. And as they piece together what went wrong, they uncover not just one error but a series of failures that led to the crash. Watch the new season of Air Crash Investigation on Mondays at 9pm, on National Geographic UK. | National Geographic UK

A Martinair flight crashes in Portugal amid thunderstorms and heavy rain, and when investigators piece together the evidence the mystery only deepens. Uncover the truth behind some of the most legendary aviation disasters on Air Crash Investigation, tonight at 8pm, on National Geographic UK. | National Geographic UK

Find out what caused the second-deadliest airplane crash in US history, brand new Air Crash Investigation ton at 9pm http://natgeotv.com/uk/air-crash-investigation | National Geographic UK

A Thunderbird pilot had to eject from a F-16C Fighting Falcon jet that crashed during a training mission near Trona, California. It's unclear what caused the crash. The Air Force said the incident is under investigation. | CNN