B737 flight crew reported an abrupt application of the aircraft brakes and injury to a cabin crew me...

Attributes
ACN	1558030
Time
Date	201807
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 640
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Procedural Published Material / Policy Flight Deck / Cabin / Aircraft Event Illness Ground Event / Encounter Other / Unknown

Narrative:

During push back; the tug driver began shouting on the interphone; 'the plane is loose...stop the aircraft! Stop the aircraft! Stop the aircraft!' I simultaneously noticed the tug appearing in front of the nose and the aircraft picking up speed backward. I immediately stopped the aircraft by applying brakes. Apparently; the tow bar pin was not connected properly to the tug. Fas (flight attendants) notified me the a flight attendant had lost his balance and hit his head on the forward galley. We returned to the gate and contacted operations for medical personnel to meet the aircraft. We coordinated with dispatch for statmd; who discussed the situation with the paramedics. Flight attendant was unsure if he wanted to go to the hospital. It was decided that he would go to get checked out. Operations supervisor was called and was to meet flight attendant at the hospital. We had a replacement flight attendant assigned. There was no damage to the aircraft. We departed uneventfully.

Original NASA ASRS Text

Title: B737 flight crew reported an abrupt application of the aircraft brakes and injury to a cabin crew member during pushback when the towbar became disconnected.

Narrative: During push back; the Tug Driver began shouting on the interphone; 'The plane is loose...stop the aircraft! Stop the aircraft! Stop the aircraft!' I simultaneously noticed the tug appearing in front of the nose and the aircraft picking up speed backward. I immediately stopped the aircraft by applying brakes. Apparently; the tow bar pin was not connected properly to the tug. FAs (Flight Attendants) notified me the A FA had lost his balance and hit his head on the forward galley. We returned to the gate and contacted Operations for medical personnel to meet the aircraft. We coordinated with Dispatch for StatMD; who discussed the situation with the paramedics. FA was unsure if he wanted to go to the hospital. It was decided that he would go to get checked out. Operations supervisor was called and was to meet FA at the hospital. We had a replacement FA assigned. There was no damage to the aircraft. We departed uneventfully.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.