Part 3 Analog vs Glass

This brings me to part 3 of the series, differences between freight dawgin it and flying nicely equipped aircraft. The picture you see above is out of an ERJ. I will be using generalizations when talking about glass cockpits because for the most part, they have the same basic lay out. There are major differences between the manufacturers (Honeywell, Collins Pro Line, ect.), but when it comes to the PFD (primary flight display) the information is pretty standard.

The instrument scan is an important part of instrument flying. A good scan is crucial to your ability to fly the aircraft. With the analog instruments you need to constantly keep a good scan going of up to 6 separate instruments. This means you need to develop a pattern that will cover all the instruments quickly and efficiently while trying to minimize eye movements. As you can see from the earlier posts, the analog instruments are all individual and separate. A glass cockpit screen will compress the standard 6 pack in analog cockpits into one screen. This compression greatly reduces the amount of looking around the instrument panel. In addition to the benefit of a smaller scan, the glass screen can overlay additional information that is not available to analog instruments.

The screen on the left is the PFD. Starting on the left of the screen you see the airspeed indicator. It is a tape indicator that is way more advanced than the old round gauge I use. For example you can set all your V speeds instead of just V1 for PNF (pilot not flying) and V2 for PF (pilot flying) because we only have one little triangle per indicator to set the speed with. I think the most helpful tool that the airspeed indicator has is the trend indicator. The airspeed indicator has a little magenta line that will overlay on the indicator to show a trend of where the aircrafts speed will be in the next 10 seconds (time may vary depending on manufacturer). This is a tremendous help and greatly reduces instrument scanning especially during an approach. For me it would completely negate having to look over at the N1 gauge to set my power on approach. When I was doing my initial in the Falcon, we flew a glass cockpit version of the sim. I got used to setting power without looking at N1. When I hopped in the plane the first few times, my scan was all messed up due to the fact I had to get used to looking away from my instruments for a few seconds to set power. The Lear is very touchy when it comes to setting power. Looking over at the N1 gauge is time consuming because you need to be precise with your power adjustments. A 1% N1 change is usually sufficient to make the airspeed change you need. You cant set the power without looking at it because if you are off by more than 1% your speed is going to get away from you.

The AI in the glass cockpit is a "good AI" from one of our aircraft on steroids. It has the same information that the good AI has plus some additional stuff. What I like about the glass AI is that you can overlay several pieces of information which would reduce your scan even further due to the fact that you can omit looking down at the HSI (I know, I know, a good pilot will never omit looking at anything, but I'm just saying this to emphasize the reduction in scan).

Next up, to the right of the AI is the altimeter. Again it has more information available than just a standard altimeter. You can set several altitude bugs for such things as DH, MDA and Missed approach Alt. The altimeter also has a vertical trend indicator that will help you out when determining when to level off.

Directly below that is the VSI. As you can see by the picture, the indicator only goes up to 3,000fpm for the ERJ. On climbouts in the Lear that would be pegged at the top of the indicator until we got above 20,000ft.

To the left of the VSI is the HSI. Again its a HSI on steroids due to the fact that you can overlay several modes on to the screen. These planes all have several modes of navigation available and the HSI can overlay each type. So you can have one pilot using the FMS mode while the other backs that up using land navigation aids on the other screen. To the left of the HSI are more information aids. You can easily see your course, DME, what color each navaid is being displayed is using and what heading your heading bug is set to. In our planes, this information is all over the place. I'd spend several seconds looking around the cockpit gathering all this information while in the glass cockpit, its all right there on one screen.

To the right of the PFD is the MFD (multi function display). These are amazing due to the wealth of information that they have. I'm not going to get into differences because we don't have anything even close to as cool as these. These displays can do everything, but what has the most relevance to this blog is how it helps pilots maintain situational awareness. On the compass rose page you can overlay your entire route and have an overhead view of what it looks like. In addition you can overlay weather, terrain, traffic and other information that will greatly improve situational awareness. We have nothing even close to this. If we want to see our route, we look at a map, weather, we turn on the radar, terrain, we look at a map and figure out where we are and where we are going, traffic, we use our eyes.

Glass cockpits are awesome. They have a tremendous amount of information available to the pilots that is not available to those with analog gauges. In addition to the extra information, the current information is presented in a format that is easy to use and scan. This reduces cockpit workload and makes flying easier. I am certainly looking forward to the days when I'll be flying glass, but I am enjoying the flying I am doing now. This will probably be the last job where I hand fly everything except cruise. Its hard flying, but its great for the stick and rudder skills. I think I'd get bored using the autopilot and flight director for everything. There are times when I'd like to use these things (bad wx), but I'm used to doing everything raw data and that's fine by me.