IR training and the importance of the VSI

[highflyer40]

I got to talking to someone today and a topic came up that I had forgot that I think is very important.

For those that are doing their initial IR training and are struggling at maintaining altitude easily. The VSI is key. it will show altitude excursions much sooner than you would otherwise see. Hopefully a good instructor would have pointed this out already but not all...

[paco]

Even though it is the first instrument to smash when you get a blockage, the humble VSI is a very useful instrument. If you get the Localiser and GP set up on the ILS, then nail the ROD you require on the VSI, you really won't need to look at the cross until the later stages.

[PURPLE PITOT]

If you are flying a modern glass cockpit IR training aircraft, i would highly recommend NOT smashing the VSI!

[mad_jock]

the other thing nobody seems to be teaching is how to trim a twin.

Its yaw -> roll -> pitch.

Any other combination will just getting you going round in circles.

[FlyingStone]

The VSI is key. it will show altitude excursions much sooner than you would otherwise see.

The best way to see trend for altitude excursion is to look at the end of the 100ft pointer on the altimeter. It shows trend much faster than VSI, which has quite a lot of lag. VSI isn't good for trend observation, it does a good job for showing a steady rate of climb/descent though...

[mad_jock]

People work different ways with there scan and both ways work fine.

Personally I use the VSI as well in the cruise. BUt if someone finds it easier to use the tip of the altimeter that's fine by me.

[hvogt]

The best way to see trend for altitude excursion is to look at the end of the 100ft pointer on the altimeter. It shows trend much faster than VSI, which has quite a lot of lag.

Unless you're flying something big that has its VSI fed from the IRS. I remember flying steep turns with a 737-300 sim in the MCC course and an assessment. Maintaining altitude was a doddle with an eye on the VSI. Never tried it in a real (large) aircraft, though.

[mad_jock]

There is a big difference between steam gauges response times and EFIS type ones.

You VSI isn't coming from the FMC on your 737 it comes from the ADC (air data computer) The trend vectors will come from somewhere else.

[hvogt]

Originally Posted by mad_jock

You VSI isn't coming from the FMC on your 737 it comes from the ADC (air data computer)

Sorry Jock, but I disagree. Indeed, the VSIs on a 737 Classic have nothing to do with the FMC, and I never said they had. However, the instruments display instantaneous vertical speed, which is acquired from the IRSs. Not being typerated on the 737 myself, I can only offer these two references:

1. what I learned during the MCC course and
2. volume 2, page 10.20.6 in a 737-400 FCOM I downloaded from the internet, where it says: "Two inertial vertical speed indicators display instantaneous vertical speed derived from the respective inertial reference system."

[mad_jock]

not rated on it either.

But in that case the 737 has IVSI's not VSI's so something completely different.

[Dick Whittingham]

The IVSI is (was) a horse of a different colour