Qfe?
 

I have the opportunity of an upcoming flight in a vintage aircraft when it has completed its re-build, one which has not flown in 39 years.
My question is this, The altimeter only has a setting up to 965, are there any recommendations from you guys on how to over-read so as a qfe of say 980 can be set??

Are you sure about that? That seems wrong to me. Getting pressure down to 965 would be very unusual.

dp

Sounds odd. Is there any chance of it being calibrated in inches, with the leading "2" ignored. Still doesn't sound very likely.

2D

Better find an altiport or aerodrome with a sodding high elevation!!
Could the country have sunk that much in 39 years?!?!?!

Look out the front. The last known aircraft without a front window was the Spirit of St Louis, and even then he had a periscope.

My apologies, I did not mean to be so abrupt. What I should have said was:

<quote> Why are you potentially going flying with an instrument that allegedly gives purpoted erroneous information, such a theoretical scenario must surely be in contravention of some important rule or law or Air Navigation Order or similar.

The appropriate Certificate of Airworthiness (or other equivalent approval) will list a Minimum Equipment List, listing all appropriate instrumentation to fly in accordance with said C of A (or other equivalent approval).

I am sure that an accurate altimeter is on the MEL. </quote>






That having been said, for good old VFR flight, a front window should still suffice.

DT

Yes, i am 100% sure,
I have just taken it out of the dash and it is a KOLLMAN 034-909

Buy a new one! - £130quid from light aero (suitable for permit aircraft)

Oh and why use QFE at all...? (slight rant...)

Kingy

It confuses Americans, do you need another reason?

Mind you, if the device doesn't go above 965hPa it's of somewhat limited use for QNH too! I'd say that it's nadgered.

G

965 can't be millibars or hPa (too low); it can't be inches without the first digit (ditto), so it must be something else.

You don't say the country of origin of this aircraft - could the units be something completely different like inches of vodka?

mm of mercury possibly?

Any chance of putting the device in a pressure chamber with a known good altimeter and cross-checking the calibrations?

G

Can't be mm of Hg, 965 mm Hg is around 38 inches of mercury or 1286 mb!

Probably not, but depends what the bottom of the scale is. I've a knackered altimeter on my desk acting as a paperweight; the subscale runs from 750hPa / mb to 1050 - that would be an equivalent range, albeit in a more sensible direction.

G

Genghis

"""I've a knackered altimeter on my desk acting as a paperweight"""

Call yourself an engineer ? Fix the damn thing :p

Since you've identified it as a "KOLLMAN" [sic], why don't you contact KOLLSMAN technical support and ask them for the answer?

www.kollsman.com

2D

I do, it's out of one of my own aeroplanes as well.

Damned silly, some previous owner / maintainer of the beast decided to use a quite ludicrous amount of permanent threadlock on the calibration screw - works fine apart from being permanently 13mb out of calibration. I couldn't think of any way of removing the threadlock that wouldn't probably nadger it even more (sealed unit, screw is surrounded by the plastic sealed casing), so relegated it to paperweight. A serviceable second hand replacement only cost me £25 so it wasn't that bad.

G


N.B. This reminds me of the time I filed an airprox after some pillock tried to fly into me off the Scottish coast. I had a worried investigator phone me up..

"Sir, you say in your report that you were at 900ft QNH"
"That's correct"
"But you don't give an altimeter setting"
"I don't recall what it was"
"Where did you get it from?"
"It read zero halfway between the low-tide and high-tide marks just before I took off from the beach"
[Long pause
"Err, there may or may-not be something wrong with that, I'll get back to you".