Settings memorised ?

[FrankM]

Hi,

here's something I've been wondering about for quite a while (but never dared to ask):

there have been accidents due to mafunctioning speed displays (e.g. BirgenAir, AeroPeru, Air Florida, ...). Now, when I was flight simming (yes, I know ...) I had some basic N1 settings memorised that helped me a lot. For example in my favorite sim model I was flying I knew that 60% N1 was pretty good for flying level 250 KIAS @ 10.000 feet in clean config. 50-52% N1 was a good choice for final approach with everything hanging out, etc.

Now, does a real pilot in a real airplane also has some basic settings memorised or are they too different according to weight and temperature ? Thanks.

[ZeroAltitude]

Hm, I think (attention: parlor talk!) that memorizing such settings, speeds etc. could be dangerous.
We know that e.g. A320 pilots can also be certified to fly the A319 and A321.
But I'm pretty sure that these different types use different settings, speeds etc, even or especially if the differences are only minute.
The way to go here would be "by the book" (again: parlor talk), i.e. reading and setting them with help of check lists, tables etc. specific to the type being flown

[flyboy2548m]

Excellent question from Frank.

We do, in fact, have some thrust settings and other tricks up our sleeve that make our job easier. Example: at most weights and at lower altitudes I can be pretty sure that 60-63% N1 will net 250 KIAS. At climb thrust, 10deg ANU will net 200KIAS, 7.5deg ANU will net 250KIAS.

There is another trick for approaches. We take our landing weight in thousand and add 20. That gives us a good initial approach thrust setting. So, if we are at 45,000lbs we set 65% N1 and that tends to net Vref+5 or so. Most of the time fiddling only 1-2% in either direction will hold the speed.

Now, let's address ZA's comments. I can't speak for Airbus guys, but at our airline we've split the CRJs into the 100/200 pilot group and the 700/900 group. Thrust settings are close enough, except that the latter models have FADEC which makes said thrust easier to set, but, more importantly, the 700/900 have slats, which gives them a very different descent profile. On the -100/200 we fly the characteristic "lawn dart" approach of 5deg AND until 30'AGL with engines going to idle at 50'AGL. The 700/900 fly a much different 1.5-2.0deg ANU approach, start flaring at 200' AGL and carry some thrust almost to touchdown. Well, there is at least one airline I know of that has its pilots fly all three types together. I can see it causing an occasional screwup on approach, but they do seem to manage fine.

[RadarContactLost]

The magic number in a 727 is 9000 pounds an hour fuel flow. Three thousand pounds per engine. If the F/E has past out during your 40 minute climb to altitude, pull'em back to 3000 pounds an engine for a good guess as to cruise power. Down low, 3000 across will hold 250 knots. And if you slow up to 200 clean, 3000 will also hold 200. And if you're down to 2 engines, 4500 on what's left will motor you around. The times I've been down to one engine in the sim I've been a bit too busy to notice fuel flow.

[flyboy2548m]

The magic number in a 727 is 9000 pounds an hour fuel flow. Three thousand pounds per engine. If the F/E has past out during your 40 minute climb to altitude, pull'em back to 3000 pounds an engine for a good guess as to cruise power. Down low, 3000 across will hold 250 knots. And if you slow up to 200 clean, 3000 will also hold 200. And if you're down to 2 engines, 4500 on what's left will motor you around. The times I've been down to one engine in the sim I've been a bit too busy to notice fuel flow.

Interesting you should mention that, RCL. We have some pilots at our airline who also set their thrust via FF. One of them used to fly the S-3, which is powered by the same engines as the CRJ and he was telling me that in the Navy that was the ONLY way they set thrust.

[RadarContactLost]

Company policy was to set EPR for TO, climb and cruise. But you think about it, there is a given amount of engery in a pound of fuel, which is why 4500 on two worked about as well as 3000 on three. You could set 90% N1for climb and it would be within a few hundredths EPR of what the chart would say.

[flyboy2548m]

Company policy was to set EPR for TO, climb and cruise.

Hehe, we don't even have an EPR indicator.