Peter wrote:
Two altimeters… well the 2nd one can be a “cheap” one
The problem with the idea of two altimeters is (especially in a light single) the opportunity cost, not the money cost. You don’t have space in the panel to spare. I would far rather have a second attitude indicator than a second altimeter. Altimeters seldom fail (and if they do, it’s usually a problem with the static system – and good luck getting an independent static system put in your EASA CofA plane for the second altimeter). However, attitude indicators, especially mechanical ones reliant on the vacuum pump fail quite a bit more frequently. But once your last remaining instrument hole is taken up by that extra altimeter that’s not going to give you all that much redundancy anyway, then you just don’t have the option for a backup AI.
Agree. A second AI is more useful. Which does not mean it ought to be mandatory!
Peter wrote:
Also, Vs of an F16 or similar is about 160kt depending on config.So I don’t think they would do an interception on a C172 with a jet.
A helicopter is much more likely, unless there is a particular hurry… During the UK 2012 Olympics they used helicopter patrols, with snipers in them.
They can’t land slowly, but they can fly slowly. I have heard of intercepts of SEPs with jets. AFAIK they would scramble a jet even after a helicopter. Helicopters would have to be deployed all over the place otherwise interception would take ages, they don’t have the performance to intercept anything other than slowish SEPs/ MEPs and I doubt they’re cheap to run. IIRC they were used to guard specific areas like during a NATO Summit where they could indeed be used to intercept and escort aircraft (small area makes the lower speed less of a factor).
I imagine that in the case you mentioned they were intended against ground targets. But they could obviously send it to intercept if they have it in the area.
Bathman wrote:
Then if I have a com box failure i would at least be legal to get home or get to maintenance using com 2.
A few weeks ago I lost my KX155A in the Nav II-position in smoke. I was really happy to have the KX165A working in the Nav I-position.
AnthonyQ wrote:
Does anyone have an opinion on the single altimeter
In the Netherlands it is quote common to have a single altimeter (VFR and IFR)
