EchoTango and domestic,
I think both of your examles illustrate a slightly different problem. That is one where debris disturbs the airflow, rather than simply partly blocking the tubes. If debris creates turbulence over the inlets, the true pitot or static pressure will not be felt in the tubes. The fact that domestic's error was greatest at low speed where pich attitude would be greatest, seems to support this explanation. SuperTed is studying for his ATPL exams, so I suspect his original question was related to this. I therefore dealt with the results that I have observed in past feedback questions.
. .SuperTed,
You might like to try these additional questions.
1.. .If the pitot pipe becomes partly blocked?
a. The IAS and ROC will be too low when climbing.. .b. The IAS and ROC will be too low when descending.. .c. The IAS and ROC will be too low at all times.. .d. The IAS will be too low when descending and too high when climbing.
2.. .If the pitot pipe becomes partly blocked?
a. The IAS will be too high when descending.. .b. The IAS will be too high when accelerating.. .c. The IAS will be too low at all times.. .d. The IAS will be too low when accelerating.
3.. .If the static pipe becomes partly blocked?
a. The IAS and ROC will be too low when climbing.. .b. The IAS and ROC will be too low when descending.. .c. The IAS and ROC will be too low at all times.. .d. The IAS will be too low when descending and too high when climbing.
4.. .If the static pipe becomes partly blocked?
a. The IAS will be too high when descending at constant IAS.. .b. The IAS will be too high when accelerating at constant altitude.. .c. The IAS will be too low at all times.. .d. The IAS will be too low when accelerating at constant altitude.
5.. .If the pitot pipe becomes partly blocked?
a. The ASI will over read and the error will be greater when climbing at constant CAS than when climbing at constant TAS.. .b. The ASI will over read and the error will be greater when climbing at constant TAS than when climbing at constant CAS.. .c. The ASI will under read and the error will be greater when climbing at constant CAS than when climbing at constant TAS.. .d. The ASI will under read and the error will be greater when climbing at constant TAS then when climbing at constant CAS.
. .My answers are:
1. d. Because the ROC indicator (VSI) does not use pitot pressure.. .2. d.. .3. a.. .4. a.. .5. b. Because the rate of change of pitot pressure is greater when climbing at . . constant TAS, than when climbing at constant CAS.