Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 404
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft
We were cleared to climb to FL410; around FL360 we got a VNAV disconnect. The Captain was flying and tried to reconnect the VNAV; it would not work. The Captain tried other vertical guidance (Level Change; VSI) and they would not work. He switched it to Autopilot B to see if that would work; and it did not. Soon after that the autopilot disconnected and would not stay engaged. I asked ATC to level at FL370 and they gave us FL390. When we both realized that both autopilots were down we notified ATC that we need to get out of RVSM (Reduced Vertical Separation Minimum) airspace. ATC gave us FL270. On the descent the Captain asked me to take the flight controls and fly the aircraft.We were trying to decided what QRH to run; but couldn't find one that covered what we were experiencing. We also noted that we didn't have any true airspeed readout on the MFD (Multi-function Flight Display) or any air data on the Engine DU (Display Unit). Also the digital engine read outs were blank as well. We did have lateral guidance with the flight directors as long as it was in LNAV; but in heading select it was just raw data. The Captain then asked ATC for a block of FL270 to FL250; so I leveled off at FL260 to give me a buffer. He was contacting Dispatch to see what type of game plan to come up with. We looked at diverting to [a nearby alternate]; but it was snowing and low ceilings. We didn't want to try to shoot an approach with just raw data if we didn't have to. We decided the best action was to continue to [original destination] because it was VFR.We did notify ATC that we could follow the RNAV arrival; but couldn't descend VIA. ATC eventually gave us radar vectors and we intercepted the LOC to [the] runway. It was visual and we could see the runway and we also did have our flight directors when we armed the approach mode. We landed without further incident. On the ground the Captain was talking to Maintenance Control and they asked him to check a code on the IRS (Inertia Reference System) box. He said it looked like there was a failed sensor with the code we gave him. We queried about what QRH we should have run and he said there wasn't one.I do think there should be some QRH or abnormal checklist for us as a crew to troubleshoot this so we know what we are dealing with.
B737-700 flight crew reported multiple autoflight system anomalies related to a failed sensor in the IRS.