Technology Notebook ContentsEffective Date: 15 June 98
Pressure Lag Error Correction
The indicated static pressure is corrected for pressure lag error by the following equation:
Where
Ps1 = Pressure at the static source - in Hg
Psic = Instrument corrected pressure at the static system indicator - in Hg
s = Static pressure lag error at the test temperature and pressure - sec
dPsic/dt = Rate of change of instrument-corrected indicated static pressure corresponding to a rate of climb in Hg/sec
The indicated total pressure is corrected for pressure lag error by a similar equations:
Where:
Pt1 = Pressure at the total source - in. Hg
Ptic = Instrument corrected pressure at the total system indicator- in. Hg
t = Total system pressure lag error at the test temperature and pressure - sec
dPtic/dt = Rate of change of instrument corrected in dicated total pressure corresponding to an acceleration and/or a rate of climb- in. Hg/sec
The in Equations (22) and (25) above will be calculated for inflight conditions from s by the use of Equation (4). Lag corrected pressure altitude is calculated from Pt1 by a form of the altimeter equation (either Equation (10) or (11)of Appendix A depending on the magnitude of the pressure.)Lag corrected indicated velocity is computed from the airspeed indicator equation as a function of qcic1 = pt1 - Ps1 (Equation (9), Appendix A).
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