Steam/mechanical vs. glass/solid state

[Marauder]

Don Kaye,

I had a CFII chew on me for "fixating" on one instrument rather than proper scanning. I asked how he knew I was only looking at one instrument. He said he watched my eyes. Obviously, with a glass panel you could not see that happening. Do you think that because all the information is in one place, that students (or any on us) will automatically see all the information without "scanning". Or are you just scanning a very small space. My initial impression is that if you were particularly concerned about airspeed, you could focus on the airspeed tape and not see everything else. Am I wrong.

What I am doing now is called the "mini scan". Since everything is in your primary glance, you are making smaller side to side and up to down scans. With the precision needles right on the Attitude Indicator, there is no need to look down at the HSI during a precision approach.

It felt unnatural for a bit, but after a few hours you appreciate all the information in one location.

[carusoam]

You will know what you are or aren't doing... But your instructor is going to have a tough time telling if you are doing a complete scan.

You will have to use your verbal mediation skills. Saying what you are doing a moment prior.

...........

I can't wait for my HSI to flake.

I'll have to seriously consider G or Aspen....with integral ADHARS, air data computer, WAAS, and GPSS...

I think that's called the whole nine yards....

Best regards,

-a-

[Piloto]

I'm not sure what glass instruments you are referring to but the two most popular ones have much wider specs than you infer. In addition, the Garmin specifically does not require an external cooling fan:

 

The Garmin G500:

 

Environmental

• -20C to +55C operating temp
• -55C to +85C storage temp
• 2 degrees C per minute temp variation
• 95% at 50C humidity
• Display equipment tested to 55,000 ft max altitude
• Internal cooling, external cooling not required

The Aspen PFD/MFD:

 

Operating Temp   -20°C to +55°C

Storage Temp   -55°C to +85°C

Max Operating Altitude (unpress.)   35,000 ft.

Cooling   Integral Fan

Max Humidity   95% at 50°C

Input Voltage   +8 to +32 Volts DC

Max Current   2.4 Amps @ 28 Vdc  /  4.8 Amps @ 14 Vdc

 

Sigmatek AI Operating Parameters:

 

Environmental Characteristics

Temperature: -30° to 50° C Vibration:   - CPS: 5 to 50 - Maximum Double Amplitude: 0.020 in. - Maximum Acceleration: 1.5 G's Humidity: 0% to 95% at 32° C Altitude: 0 to 40,000 ft.

 

The inherent problem with steam gauges are the moving parts. Note the maximum acceleration for the SigmaTek AI.  When I lived in upstate New York, I saw more failures, even with new replacement gyros than I have been seeing here in the mid-Atlantic area. I'm sure it is because I never properly or fully warmed the cockpit on those 0 degree Fahrenheit days I flew often. As for your battery master relay failure scenario, my Aspens will actually go to battery power. The only way to turn them off if you lose main electrical power to the plane is use the REV button and manually power them off. As well, the requirements for mechanical backups only requires a separate source AI. With the extended battery pack in the Aspen, you can legally remove both the ASI and altimeter from the panel.

The -20C to +55C comes from the RTCA DO-160 document for certification. But what they don't tell you is that there is fan in the test heating chamber to keep the air temperature even so there is no hot spots. But if you turn the fan off the inside temperature in the unit tested can rise well above +55C. Also the test is performed at sea level pressure were the air is more dense and provides better cooling than at 10,000ft.  

 

Battery packs are nice to have but I have yet to see one that outlast the fuel onboard. Not an issue when you are close to airports but when you are over water 500nm from shore at night you wish you had that old fashion altimeter, IAS and other steam gauges when a power failure happens.

 

José 

[Marauder]

That is the whole purpose of standardized electronic testing. To provide you a working range for the electronics for the certification you are looking for. Turning off the fan in your example, is like putting a transient spike through a circuit. It will fail because it is out of the design spec. No different than running a vacuum gyro at too high of a vacuum. It will fail too. As for batteries, I agree that unless you are flying the Space Shuttle, a battery has a defined limit. If I were flying 500 nm from shore, at night, I certainly wouldn't be trying to be Lindbergh and would be flying something with more redundancy. Sent using Tapatalk

[donkaye]

Don Kaye,

I had a CFII chew on me for "fixating" on one instrument rather than proper scanning. I asked how he knew I was only looking at one instrument. He said he watched my eyes. Obviously, with a glass panel you could not see that happening. Do you think that because all the information is in one place, that students (or any on us) will automatically see all the information without "scanning". Or are you just scanning a very small space. My initial impression is that if you were particularly concerned about airspeed, you could focus on the airspeed tape and not see everything else. Am I wrong.

 

As a flight instructor, even with the legacy instruments and sitting in the right seat, I can take in the whole six pack in one overview.  Anything that changes can be instantly seen.  Sitting in the left seat, that is a little more difficult, since the instruments appear a little more spread out due to their closeness, however it it still possible to take them in peripherally and notice any change in any one of them immediately with experience.  So with experience even the legacy instrument's information can be taken in quickly in one overview if you know each instrument's function so well that almost no thought is required in their interpretation.

 

All that was said above applies much more easily to the glass panels because, once the new tapes presentation is fully absorbed,  the compact presentation of the six pack makes taking in the whole situation at a glance much easier than with the legacy instruments in my opinion. 

[fantom]

What I am doing now is called the "mini scan". Since everything is in your primary glance, you are making smaller side to side and up to down scans.

Chris...how does your AOA fit in your mini scan?

Don...your new panel is amazing. What took you so long to covert it's a pleasure having you on MS.

Very informative thread...thanks guys!

[Marauder]

Chris...how does your AOA fit in your mini scan?

Don...your new panel is amazing. What took you so long to covert it's a pleasure having you on MS.

Very informative thread...thanks guys!

Haven't installed it yet Gary. Just haven't been able to get on the mechanic's schedule with the weather we have been dealing with here. I am planning in having it sit on top of the AI or perhaps the side of the Aspen. The LEDs are pretty noticeable.

Sent using Tapatalk