infrequentflyer789, #288
There's your one teeny weeny problem right there. Wind speed might usually
be fairly constant short term, but then pitots (properly heated) don't
usually ice up either. Pitot icing is often in the vicinity of thunderstorms,
and rapid changes in wind speed can be found... guess where.
Agreed, but in the existing system, pitot data will be subject to filtering
and may already include historical data to provide some sort of predictive
capability. The processing will reject out of range transient data. When a
storm is entered, things get more dynamic, but again the software will adapt
to this, changing it's filter parameters if required, to optimise the
measurements. If this were not already the case, flight deck values would be
unreadable.
In short, I think your scheme still has the common mode failure that the
3 redundant pitots have - the same external conditions may mess up the
pitots and your inertial backup.
Additionally, you've now added another failure mode - if the pitot airspeeds
vary wildly (but accurately) due to rapid air mass changes, is your inertial
mixing going to vote out the correct data ?
It depends on how the data is processed and it's not a case of one data source
or the other in competition, rather a synthesis of the two, where the error
characteristics of both are given less weight in the calculations and the
strengths given more weight. The idea is to model the characteristics of all
the sources under all conditions of operation. The filters and processing can
then be matched to provide a more accurate and consistent result than from either
source alone. A more robust system in terms of transient events and redundancy...