terry

On Apr 17, 9:29 pm, "Mortimer Schnerd, RN" <mschnerdatcarolina.>
wrote:
> terry wrote:
> > I am confused by this practice commercial nav question. ( at least I
> > am confused by the answer in the book which was b. but I think both a
> > and c are correct), but I appreciate some other opinions.
>
> > Day 1 Altimeter reads elevation of 1390 feet with 1013 HPa set on
> > subscale
> >         ( thats equivalent to 29.92 inches of Hg for the US folks)
> > Day 2 Altimeter reads elevation of 1000 feet
> > Assuming the altimeter subscale was not changed between day 1 and day
> > 2 it could be said that
>
> > a. The QNH is higher on day 2
> > b. The QNH is lower on day 2
> > c. The pressure altitude at the airport is lower on day 2
> > d.  The atmospheric pressure at the aerodrome has not changed.
>
> Their answer confuses me too.  It seems that if the altimeter setting wasn't
> changed from day 1 to day 2, yet it reads a lower altitude, the barometric
> pressure must have risen.  The altimeter will translate lower pressure to higher
> altitude and higher pressure to lower altitude.  So I think the answer should be
> "a".  And if I accept "a", I have to accept "c" as well, as you did.
>
> I'm probably going to regret posting this because I'm going off the top of my
> head but it wouldn't be the first time a test guide had the wrong answer posted.
>
> Alright guys.... pile on!

No, its not the first time I have come across wrong answers either,
but it is the first time I have come across a wrong answer, pointed it
out to the author and was still told I was wrong. ( I dont want to
name the said author because I think he otherwise has published some
very good material and I am sure he will soon realise his mistake.. I
just wanted to be absolutely sure I was right before I responded to
his response!)
Thanks Mort