Gulfstream IV flight crew reported the outer panel of a passenger window blew out during cruise and was ingested by the engine. Flight crew returned to departure airport and landed.
Synopsis
Gulfstream IV flight crew reported the outer panel of a passenger window blew out during cruise and was ingested by the engine. Flight crew returned to departure airport and landed.
Narrative
We departed the ZZZ airport at XA00 enroute to ZZZ1. We were repositioning the airplane to pick up passengers and we had 3 crew members on board; two pilots and one cabin attendant. We were in the climb phase of flight and had briefly leveled off at FL350; waiting to climb to our final altitude of FL410. We suddenly heard a loud bang noise and both crew members looked at each other and said 'What was that?' I looked down at the engine gauges; but everything appeared to be normal. There were no amber; nor red indications. The vibe sensors showed no abnormal vibrations. Our cabin attendant came up to the cockpit and asked if we had heard the noise. The noise sounded familiar to me and I initially thought that we had experienced a compressor stall. We had just flown through a bit of ice and I was wondering if we had possibly ingested some ice into the engines causing a compressor stall. I then told the First Officer that I wanted to walk back to the cabin and inspect the engine nacelles and make sure that we didn't have ice building up. As I walked up to the right side windows to look at the engine; I immediately noticed that a passenger side window (outside panel) had blown out. I returned to the cockpit and discussed the problem with my crew member. We made the decision to turn the airplane around and head back to ZZZ. We alerted ATC of our situation; and they asked if we would like to [request priority handling]. Having analyzed the situation; I decided that was not necessary. The airplane was perfectly controllable; the engines appeared to operating normally; and the pressurization system was working normally as well. As a precaution; we started an early descent and I asked the cabin attendant to sit on the jump seat with her seat belt on; just in case the inner window should happen to also blow out. I asked ATC to communicate with our company and let them know that we are coming back. The controller relayed the information and had told us that our company had decided to [request priority handling] on our behalf. The flight back to ZZZ was normal and uneventful. After landing; we were met with the fire crew for an inspection. When we exited the airplane and walked over to the right side; it became evident that the window that had blown out; had entered Engine number 2. There was a dent on the engine nacelle and there were several fan blades that had dents. I am not aware yet of the extent that the engine has been damaged; however; the engine showed no signs in the cockpit of having any abnormalities. There were no vibration indications and the engine made normal power.
Second reporter narrative
We departed ZZZ at XA00 to reposition to ZZZ1 to conduct a passenger flight. There were three crewmembers onboard the aircraft including myself; the Captain; and the cabin attendant. We were in the climb phase from ZZZ when we leveled off at FL350 planning to climb to our final altitude of FL410. At that moment the Captain and I heard a loud bang noise. We immediately checked our instruments; including engine readings; and saw no abnormalities. We discussed that it sounded like a possible compressor stall and that maybe ice had been ingested into the engine. The Captain decided to walk back and check for possible icing around the engine. When he returned; he stated that the third passenger outboard window on the right-hand side of the aircraft had blown out. Again; we checked the engine readouts as well as the pressurization system and all were operating as normal. We discussed our course of action and decided that we would return to ZZZ. We let ATC know that we would like to return and then we began our descent and turned back into ZZZ. We had no delay in our descent as a precaution. We asked ATC to notify our company that we were returning to ZZZ. ATC then asked if we would like to [request priority handling] but we decided the situation did not warrant one based on that the aircraft and all systems were operating as normal. We monitored all systems throughout the descent into ZZZ and there were no abnormal indications. ATC then informed us that our company had [requested priority handling] for us. The remainder of the flight back and landing into ZZZ was uneventful. We were met by a fire crew that inspected us and escorted us back to our base of operations. Upon exiting the aircraft; we noticed the broken outer window; from our observation the center of the outer passenger window had broken off and entered the #2 engine. There was visible damage to the engine nacelle and several fan blades with dents in both. Before observing the damage we did not think the window piece had entered the engine as we saw no abnormal indications such as vibrations or fluctuations and the engine operated as normal.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.