B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 177; Flight Crew Total 2351; Flight Crew Type 2351
Situational Awareness; Troubleshooting; Confusion; Communication Breakdown
Aircraft Equipment Problem Critical; Deviation - Speed All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Aircraft Damaged; Flight Crew Overcame Equipment Problem; Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action; General Flight Cancelled / Delayed
Human Factors; Procedure; Aircraft
During climb out; FA (Flight Attendant) called on intercom to report a very loud banging noise behind the wing area; aircraft right side; row 31. FA said it sounded like someone pounding on the fuselage with a sledgehammer repeatedly. We leveled off at FL280 immediately and reduced speed from 280 KIAS to 250 KIAS. I asked the FO to look for a nearby field with good weather.  FA recorded the noise via video on her cell phone and brought it to the cockpit. After reviewing the video; we decided to divert to ZZZ. We notified dispatch and coordinated with the FA's and informed the passengers. During the descent and configuration of the aircraft for landing at ZZZ; with the flaps at 5deg; I called for Flaps 10 while the aircraft speed was at 209 KIAS. I immediately said 'delay that stay at flaps five.' I believe the FO moved the flap handle out of the 5 detent and returned it immediately. The flaps remained at 5 degrees and I continued to slow the aircraft. I called for gear down an Flaps 15; flaps 25; flaps 30 landing checklist. I noticed the stick shaker indicator on the airspeed tape was in an unusual position and cross checked the configuration to find the flaps were at 5. We were at approximately 1200 feet when I announced 'going around'; but did not hit TOGA as I did not want GA thrust. At this point; the FO and I were convinced that the two problems were related; that there was some structural damage to the flaps.We climbed to 5;000 feet and referenced the Checklist for FLAPS - TRAILING EDGE FLAPS DISAGREE. We returned the flap lever to 5; then selected 2. The flaps retracted to 2. The checklist directed us to 'Proceed normally.' We had a discussion about what that meant and were not comfortable with extending the flaps again; with suspected mechanical damage to the flaps already existing. We got a phone patch with Maintenance Control and dispatch on HF and discussed the two issues and our checklist. They had no additional advice. We discussed the plan to land in the current flap configuration (flap 2); using the flap up speeds with Maintenance Control and dispatch. The FO had already assessed the landing distance and we referenced the FLAPS- TRAILING EDGE FLAPS UP LANDING checklist. We landed on RWY XXL at ZZZ; at VREF 40 + 40 + 5. I used auto brakes 3; and rolled to the end of the runway. We had the fire/rescue look us over for damage prior to proceeding to the gate. They reported a large cable hanging from the satellite antenna. The PSEU (Proximity Switch Electronics Unit) light came on after landing. The FO and I debriefed the events in detail post flight and during the next two flights. It was not until the following morning; that I realized that in all likelihood; I caused the flap malfunction by calling for flaps 10 at 209 KIAS. The SATCOM antenna seal failure noise was significantly concerning; and I assumed the flap issue was directly related.
First Officer reported a SATCOM antenna became dislodged on take off; repeatedly striking against the fuselage. Flight crew elected to divert for a precautionary landing.