Boeing 787s must be reset every 51 days or 'misleading data' is shown (2020)

Speculated Technical Causes of the 51-Day Bug

• Multiple comments try to match 51 days to counter overflows.
• Some compute 2³² milliseconds (~49.7 days) and note it’s close but not exact; others argue the mismatch and timing details make this unlikely.
• Later links point to a root-cause analysis suggesting a 47‑bit timestamp at 32 MHz fits the 51‑day duration better.
• Another thread attributes similar bugs elsewhere to IEEE‑754 double precision losing integer precision around 2⁵² nanoseconds (~52 days), though this is debated and partially corrected.

Reboot-as-Fix and Comparisons to Other Systems

• Many see “reboot every X days” as routine in embedded/avionics, and acceptable if captured in maintenance procedures.
• Others find this culturally worrying for safety‑critical systems and argue it’s a sign of inadequate engineering.
• Comparisons are made to Windows 9x uptime bugs, Airbus A350’s 149‑hour reset directive, routers with DHCP lease exhaustion, cars and EVs needing periodic power cycles, Raspberry Pis and TVs that require reboots.

Aircraft Uptime and Maintenance Practices

• Debate over whether airliners are ever actually powered continuously for 51 days.
• Some say planes are almost always on (flight or ground power) to maximize utilization; others assert parked aircraft are typically powered down outside of active work.
• Routine checks (weekly maintenance, heavy checks) are cited as limiting true continuous uptime, but commenters note that “reboot” on an aircraft is usually a hard power cut, not graceful shutdown.

Safety, Risk, and Boeing’s Reputation

• Strong criticism of Boeing’s recent track record and culture; others counter that 787s have had no fatalities and commercial aviation overall has extremely high safety (multiple “nines”).
• Disagreement over whether such bugs warrant severe penalties vs. being minor issues mitigated procedurally.
• Extended argument over how to measure transport safety (per passenger‑mile vs per trip) and comparisons to trains and elevators.

Software Process and Certification

• Some stress that aviation software (e.g., DO‑178C Level A) undergoes very rigorous verification, timing analysis, and coverage testing.
• The 737 MAX is discussed as a system‑specification and safety‑process failure rather than a simple “bug,” with detailed critique of MCAS design, sensor redundancy, documentation, and economic pressures.
• Others argue that culture/regulation must push toward designs that avoid such failure modes entirely.

Networking and IPv4/IPv6 Tangent

• Side discussion about onboard Wi‑Fi: DHCP lease exhaustion, use of private 10/8 space, and VPN conflicts when both plane and corporate networks use overlapping ranges.
• IPv6 is proposed as the “real” fix, but commenters lament slow industry adoption and economic inertia.

Anecdotes and Related Incidents

• Pilots and enthusiasts share stories of 787 auxiliary power issues, APU and RAT (ram air turbine) behavior, and emergency power scenarios.
• Historical incidents like the F‑22 International Date Line bug and a submarine sensor drift issue are cited as analogues.