Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Aircraft Aircraft Damaged
Aircraft; Equipment / Tooling
We unknowingly flew an un-airworthy from ZZZ to ZZZ1. We had an inoperative APU on our aircraft. We performed the external air pneumatic start checklist. During the start (maybe 45 seconds in) we heard a loud bang. I monitored the engine indications for any sign of damage or an irregular start attempt. The ground crew then stated to let them know when they could disconnect ground air and power; the start was not finished yet so I told them to wait. I had the First Officer look out his window to see if he could see the engine and make sure everything looked okay; it did. We then asked the ground crew what had happened; they said 'The air hose popped out early by itself; it broke'. By this time we had a normal start and I told them they could disconnect ground power and the air. They did so and told us they were ready for push; at no point did they tell us that the air hose had damaged the aircraft when it broke/popped out. We continued the flight to ZZZ1 without further incident and noticed the damage on our post flight walk around. We immediately notified maintenance control and the company of the damage.
[Report narrative contained no additional information.]
E175 Flight Crew reported the air hose from the air starter unit unexpectedly disconnected from aircraft; causing damage to the aircraft.