B757-200 pilots reported a navigation deviation and low altitude alert from ATC after a programming error in the FMC.
Synopsis
B757-200 pilots reported a navigation deviation and low altitude alert from ATC after a programming error in the FMC.
Narrative
We arrived to the plane early and started our flows. After loading the flight plan and departure procedure during normal ground operations; we received an ATC route change via CPDLC. It was loaded; executed; and accepted together as a crew. However; due to inexperience; I did not recognize until later that this situation is when the departure procedure can be dropped from FMC flight plan. We then discussed the complex engine failure procedure at length; going over all the details for the procedure. The complex engine failure procedure included 2 fixes with 2 DME rings and radials which added more items to the nav display; so it was not apparent that the departure dropped from the FMC. Runway XXL was still on the display; and had not been dropped. The temperature was 28C with high density altitude for ground operations; which caused slower than normal engine starts; adding a bit of distraction just prior to taxi. The crew was not familiar with ZZZ and there were a few taxiway NOTAMs with closures that were discussed when planning the taxi to Runway XXL. When cleared for takeoff; winds were suddenly gusting up to 19 knots of straight crosswind of 260@15G19; which was not in the forecast; with moderate turbulence expected up to 13;000; and Aircraft Y on final that was cleared to land on Runway XXL right after we received our takeoff clearance. The Captain lined up the plane and both pilots verified the runway; and exchanged aircraft control so the FO would be pilot flying. Crew took off; checked in with ZZZ departure; and was told to climb unrestricted to FL190. Crew configured for climb on flap retraction schedule; selected VNAV; selected climb direct; and engaged the autopilot for the RNAV SID; which then followed FMC guidance directing a right turn to the next point in the FMC; which was ZZZZZ. ATC advised crew of a low altitude alert; and asked crew which SID they were assigned. Pilot monitoring responded with the ZZZZZ5; and ATC gave crew a vector of 360; which pilot flying selected. The Crew then realized the ZZZZZ5.ZZZZZ SID was dropped from the FMC prior to takeoff; and neither pilot recognized it. ATC notified crew and advised them to contact ZZZ approach. We contacted ZZZ approach after the flight; and initiated the report process.As a crew; we failed to trap the error associated with the route change clearance; as described in the AOM (attached). We discussed this error at length during the flight; realizing we had very rarely seen this situation; and the various other factors of unfamiliar airfield; weather; traffic; climb direct; and complex engine failure procedures in a high terrain environment added just enough competing factors to prevent either one of us from trapping the error. Since the runway had not been dropped from the FMC; and the addition of fixes for the complex engine failure procedure; it was not as apparent that the SID had been deleted; but neither crew member re-verified the SID constraints after the new clearance was received; only during the initial cockpit setup through the pre-flight checklist. After realizing this error; both pilots discussed adding this crosscheck to their pre-flight flow to ensure the SID is reloaded and verified after a new route clearance is received; as well as rechecking the legs page of the FMC to ensure any altitude or speed constraints associated with the SID are still programmed in the FMC immediately prior to takeoff. As the first officer; I should have reloaded the SID after the route modification; and did not recognize the situation described in the AOM. I suddenly remembered while trying to figure out how we were not on the same page as ATC. As the pilot flying; I should have recognized that the right turn to ZZZZZ directed by the FMC was too early and not at the correct altitude as the right turn to ZZZZZ in the SID. I thought it seemed off when the flight director started a right turn; but incorrectly attributed it to the climb unrestricted guidance; sincemy focus was on takeoff and aircraft configuration while flying through the wind and turbulence. As soon as we received the vector back on course; I realized my errors. I am so disappointed and embarrassed that I let a change in route clearance turn get so far off course; and not flying the SID. I should have been more familiar with the SID and not let the complex engine failure procedure overshadow normal procedures. I have reviewed the procedures with the captain; and we've discussed preventive measures and better CRM habits during high-workload environments to ensure this never happens again.
Second reporter narrative
While completing normal ground operations and the block out checklist procedures. The crew received a route change via CPDLC from ATC. The crew reviewed; loaded; verified; and accepted the clearance. The crew did not trap the error of the ZZZZZ5 departure dropping out of the FMC Flight plan. During the CRM/Safety Briefing; the crew discussed in detail the following threats presented with the flight. Such as; high terrain; high DA; moderate turbulence forecast up to 13;000 (not engaging the A/P at 200 AGL) to include the complex engine failure procedure departing on Rwy XXL which included 2 fixes with 2 DME rings and radials. This additional information on the Nav display may have contributed to the error not being trapped. FO/PF did an excellent job with the PF briefing. The crew discussed the threats presented.An additional distraction was during engine start; due to the high DA (Density Altitude) and temperature of 28 degrees C. The engines started very slowly. The other threats considered prior to taxi was the taxiway closures and the unfamiliar airport for the crew. The crew taxied to Rwy XXL. As the crew was cleared for T/O; the winds started gusting reported 26015G19. Also; aircraft Y was on final and cleared to land on Rwy XXL.Once lined up and Rwy verified; the crew exchanged aircraft controls and began T/O Roll with TO1 takeoff. As previously briefed; LNAV was engaged and VNAV at 1000AGL. The A/P was engaged after VNAV. On departure; PM contacted ZZZ Departure and crew was immediately directed to climb unrestricted to FL190. All occurring while; retracting flaps and getting the aircraft cleaned up on schedule. Once the A/P was engaged; the aircraft began a right turn too early; but in the same direction as the SID. This also; added a threat.ATC advised the crew of the low altitude alert and queried the crew as to which SID was assigned. Crew responded ZZZZZ5 Departure. ATC directed the crew to heading of 360 degrees. Crew immediately followed ATC instructions. Crew was notified by ATC and advised to contact ZZZ departure. Upon completion of flight; crew contacted ZZZ [Departure] as instructed and provided them with the requested information.Once at cruise altitude; crew thoroughly discussed/debriefed how the threat developed and how to mitigate the error in the future. Crew determined the error occurred with the route change during ground operations which led to the departure procedure being deleted from FMC flight plan. Unfortunately; the crew did not re-verify the SID constraints. Crew discussed ensuring to cross check; verify the SID; and any other new route clearances received.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.