Hudson
17th Apr 2005, 05:03
Refer to ENR 1.5 - page32. Sub para 7.3 ILS Altimeter checks.
I see that para 7.3.1 (a) states: To ensure obstacle clearance, both LLZ and glideslope should be maintained within half scale deflection (or equivalent on expanded scale).
In that case, if the normal LLZ deviation scale (737 EFIS for example) is one degree per dot, and the expanded scale is half a degree per dot, then it seems to me that that the expanded scale is not applicable when it comes to the obstacle clearance LLZ requirement stated in ENR 7.3.1 (a)?
To put it another way: if you are on the ILS and you are exactly half scale deflection on the LLZ normal scale (one degree per dot), the expanded scale would show the LLZ needle beyond or outside the limits of the expanded scale. Therefore there is no point to the ENR additional statement of: "or equivalent on expanded scale". - because there is no equivalent, is there?
Maybe I have read it all wrong of course, but any comments would be appreciated.
I see that para 7.3.1 (a) states: To ensure obstacle clearance, both LLZ and glideslope should be maintained within half scale deflection (or equivalent on expanded scale).
In that case, if the normal LLZ deviation scale (737 EFIS for example) is one degree per dot, and the expanded scale is half a degree per dot, then it seems to me that that the expanded scale is not applicable when it comes to the obstacle clearance LLZ requirement stated in ENR 7.3.1 (a)?
To put it another way: if you are on the ILS and you are exactly half scale deflection on the LLZ normal scale (one degree per dot), the expanded scale would show the LLZ needle beyond or outside the limits of the expanded scale. Therefore there is no point to the ENR additional statement of: "or equivalent on expanded scale". - because there is no equivalent, is there?
Maybe I have read it all wrong of course, but any comments would be appreciated.