Laversab 6600, User Manual, Page: 36 / 79

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Pt output Ps2 output Ps1 output
Units Rate Units Rate Units Rate
knots 500 knots/min Feet 3000 feet/min Feet 3000 feet/min
Mach 500 knots/min meters 3000 feet/min meters 3000 feet/min
mph 500 knots/min inHg 4.000 inHg/min inHg 4.000 inHg/min
kmph 500 knots/min mbar 4.000 inHg/min mbar 4.000 inHg/min
Pt inHg 4.000 inHg/min Diff. inHg 4.000 inHg/min
Qc inHg 4.000 inHg/min Diff. mbar 4.000 inHg/min
Pt mbar 4.000 inHg/min knots 500 knots/min
Qc mbar 4.000 inHg/min kmph 500 knots/min
EPR 4.000 inHg/min
Limitations of “engineering” rate:
The target “engineering” rate in inHg/min can be set to any value between 0 and 30.000
inHg/min. However, this rate is limited by the Limit for Maximum Altitude Rate (Max.
Ft/min) (section 3.5.2). While the Ps1 or Ps2 outputs are being ramped towards the target,
if the “engineering” rate translates to an “altitude” rate which exceeds the Limit of Max.
Ft/min, then the effective target Rate will be the Max. Ft/min Limit value.
For example, assume that the “engineering” rate is set to 4.000 inHg/min and the Max.
Ft/min limit is set to 10,000 ft/min. Assume that the Ps1 output is being ramped from
30.000 inHg to a target of 5.000 inHg. At approximately 9.0 inHg the rate of 4.000
inHg/min translates to 10,000 ft/min. Above 9.0 inHg the rate of 4.000 inHg/min
translates to less than 10,000 ft/min, whereas below 9.0 inHg the rate of 4.000 inHg/min
translates to more than 10,000 ft/min.
Therefore, while the Ps1 output is above 9.0 inHg the Rate target will be 4.000 inHg, but
once the Ps1 output goes below 9.0 inHg, the Rate target will be set to 10,000 ft/min. The
10,000 ft/min value will translate to a reducing value in inHg/min as the pressure reduces.
At 5.000 inHg, the 10,000 ft/min will translate to only about 2.400 inHg/min.
On the 2-output format, you will notice that although the target Rate is set to 4.000 inHg,
once the Ps1 output goes below 9.0 inHg, the Actual Ps1 Rate will slowly reduce from 4.000
inHg/min to 2.400 inHg/min as the Ps1 output approaches its target of 5.000 inHg.
Note: This limitation of the “engineering” rate is imposed only on the Ps1 and Ps2
outputs. This limitation does not directly affect the “engineering” rate for the Pt output.
However, the “engineering” rate for the Pt output may be indirectly affected by the rate
change of the Ps1 output due to other possible constraints of maintaining specific
differentials between the Pt and Ps1 outputs.