Date: 202201
Aircraft: B737 MAX Series Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Aeroplane Flight Control
Component problem: Improperly Operated; Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Workload; Time Pressure; Troubleshooting
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Attendant
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Landed As Precaution; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: Departed [Runway]  XXL. First Officer's takeoff. Takeoff and rotation were normal.  Climbing through 400 ft. we heard a chime. Our clearance after takeoff was to turn left and fly heading 350 so when we heard the chime we were in a climbing turn and had just contacted Departure.  Our work load was very high so by the time I looked for the FA (Flight Attendant) call light and did not see it illuminated. Thinking it may have been a mistaken chime I waited to address the chime. The FO (First Officer) put the autopilot on and I picked up the handset but there was no answer. We continued the climb to 23;000 ft. and heard another chime at 7000 ft. I told the FO he had the radios and I answered the handset. The FA stated they thought we had a tail strike. I asked them to standby and I would call them back as we had just received an ATC clearance to FL230. As we passed 10;000 ft. I ran the TAIL STRIKE checklist. I directed the FO to fly and handle ATC. I contacted the FA again to ask if both of the aft FAs thought we had a tail strike and they replied yes.  I requested a level-off at 16;000. We then advised ATC. I sent a Dispatch a call me and informed Dispatch and Maintenance Control. Maintenance Control indicated there was no further guidance he could provide. I inquired as to whether we should burn fuel to get to max landing weight or land over weight. At that point Maintenance Control suggested we speak to the Chief Pilot. The Chief Pilot suggested doing what we could to burn fuel and reduce weight but stated an over weight landing was relatively insignificant.I spoke to the FA and asked if it was possible the noise they heard could have been from the cargo area or an overhead bin. They both stated they felt it was a tail strike. I then ran the [briefing checklist]; I explained the type; no evacuation; no special instructions; and about 20 minutes to landing.  I then informed the passengers that we had a maintenance issue and we would be returning. I added that there would most likely be emergency equipment near the runway but that it was standard practice for a return. We requested a descent to 10;000 ft. to run the checklist which called for us to depressurize the aircraft.  We did continue to fly away from ZZZ but slowed to 240 kts. This was intentional as I felt it would be better to deal with this with less ATC congestion which we would have and in Approach's airspace.We then attempted to pull up landing data and found we could not get it to return information. If this is normal; I would suggest Dispatch should send this automatically. My understanding is that Dispatch has to change the destination for this information to be available so I'm not sure if that was the issue. I pulled up landing distance from the FM but we still needed landing performance data so we sent a message to Dispatch requesting the data. Since we would be landing over weight; we decided it may be best for me to do the approach and landing. We requested a descent to 600 ft. and manually depressurized the aircraft per the checklist. This procedure was distracting since we would open the outflow to achieve 500 FPM climb but every power change would affect the rate of cabin climb or descent.  While the checklist calls for the airplane to be depressurized at 10;000; I felt that if we were able to pressurize at 16;000 ft. we could certainly do so at 6;000 ft. so for passenger comfort I felt it was better to wait until 6;000 to depressurize. We elected to land flaps 30 and auto brakes max. 40 miles from the airport we selected flaps 5 and gear down. During the approach; we configured to flaps 30 at G/S capture (4000 ft.).The approach and landing were uneventful. We completed the parking checklist and sent a report for possible tail strike and over weight landing.Upon inspection after returning to the gate; Maintenance inspected the aircraft and determined there was absolutely no tail strike. Once the passengers were off the aircraft; I debriefed the FAs. One of them stated a previous Captain had told them to be vigilant about listening for tail strike since the 737 MAX is prone to doing so. I contacted the Chief Pilot who did an amazing job. We discussed the event and he inquired as to whether we felt OK to continue. I spoke to my FO and we both agreed we were fine to continue.


Second narrative: We departed on [Runway] XXL on the ZZZZZ departure-my leg. ATC initially gave us a left turnout to heading 350 up to 4;000. I performed what I believed was a normal smooth slow rotation and climbout. Around 3;000 ft. we received a Flight Attendant call- which we were still in the midst of climbing; turning and clearing the cloud deck in the area; along with finishing up accelerating and cleaning up the configuration. We both thought it was odd- and I brought the autopilot on to reduce the workload. The Captain used the handset to talk to the FA's but there was no answer.We received the ATC call of direct ZZZZZ1 and up to I believe was FL230 (It was something in the 20's). The chime rang again-- the Captain talked to the Flight Attendants and then told me the aft Flight Attendants believed that we had a tail strike. Upon reading the QRH; the Captain said that the requirement was to land at nearest suitable airport. We both thought that my rotation was not uncommon or excessive; however we had a few last minute changes to loading and baggage that may have moved the CG that could have been a concern.We continued on the departure but stopped the climb at 16;000 and slowed the aircraft to approximately 250 kts. We both thought we shouldn't continue the climb; and we were carrying 6+ hours of fuel. I took over ATC calls and flying the aircraft while the CA (Captain) sent a call me and talked to Dispatch; Maintenance.The Captain had an extensive conversation with all groups. During this conversation; the Captain directed me to request priority with ATC; tell them that no assistance was needed; and that we will need to return to ZZZ; but will coordinate when we are ready; I relayed the SOBs (souls on board) and fuel remaining as well. When the Captain finished his call; we talked about our plan; which was to return to ZZZ; he would perform the overweight landing; and that we would need to depressurize the cabin. I continued flying duties while he gave the items to the Flight Attendants and informed the passengers of the situation. He informed the passengers that Crash fire rescue may meet us at the runway; and to not be concerned - as it is normal procedure.We descended to 10;000 and performed the depressurization checklist near ZZZZZ2. We started a slow depressurization per the QRH; at a cabin rate of -500 fpm. This was surprisingly difficult to control with the outflow valve at this altitude.Around ZZZZZ2 intersection we turned back to ZZZ; and were eventually cleared down to 6;000. At 6;000 we opened the outflow valve and confirmed that the pressure differential was zero--we noted that we should attempt to do any more step downs is Vertical Speed to minimize the affects on our ears.  During this time; we reprogrammed the box; we reset the cruise altitude; landing altitude; ran the appropriate QRH pages; talked about our plan to return to [Runway] XXR; coordinated with ATC; and gathered landing performance data. We chose a flaps 30 landing; with autobrakes MAX. We struggled getting the landing data; and in one of the many communications with Dispatch I asked for flaps 30 landing numbers--which we received shortly after. We also put out flaps and slowed the aircraft to 230 kts; and about 40 miles out put down gear to help burn down fuel to minimize the overweight landing.During this time; we transferred controls several times--reflecting on that after the event- we both agreed how well that went. We completed a discussion about the landing plan; and finished the descent checklist. ATC vectored us in outside ZZZZZ3 at 4;000 ft. on the ILSXXR; and we completed configuration and the approach and landing went nominally.Arriving at the gate; we met Maintenance and inspected the aircraft- there was no indication of a tail strike. I thanked the CFR team for coming out to meet us; and told them that we didn't have any indications of a tail strike.In a later discussion with the CA; he said when he debriefed the Flight Attendant she stated that a CA from a previous trip had asked her to notify them if they heard anything unusual; as the Max's were prone to tail strikes. It is felt that this may have created a situation where the Flight Attendant was making a judgement call based on not knowing what a tail strike actually sounds like. She may have heard cargo; galley items; things in the galley crown area or bags shifting in the overhead bin that made her think we struck the tail.


Synopsis: B737 MAX flight crew reported that during departure; flight attendants advised the flight crew of a possible tail strike during takeoff. The flight crew returned to departure airport where a maintenance inspection determined that no tail strike had occurred.