Landing gear up warning

anthonyxritchie

I love flying!
Joined
Jun 27, 2018
Messages
2
I'm trying to put a gear up warning to let me know that my gear is still up when it ought to be down. I have a few questions.

1. I tried to wire the gear down sensor to one of the unused "contact" pins on the 37 pin EMS harness. I tried a couple different pins and got nothing. It seems completely unresponsive to any voltage I put on the pin. The EMS display shows "R5" (range 5) whether there's 24V 12V or 0V on the wire. Am I missing something with setting up the contact pin? Pin 9 (my Pitot heat status) in is working fine as a "contact" sensor but that was already set up when I bought the system. I can't tell what's different about that one. I went into sensor input assigned the pin as a "contact" with name "gear" and put the sensor on the EMS display. I even messed with the ranges to make sure there were different ranges assigned to different input voltage.

2. Assuming I can get 1 figured out, is there a way to make the EMS warning aware of my airspeed within the Dynon system. Otherwise I can always wire in a separate airspeed switch but since the SV system already knows the airspeed it seems silly to have to put another device in that knows the airspeed.

3. this is more off topic but I'm very curious, is there a good reason that there isn't a way to have a gear up warning driven by GPS altitude AGL? I know big fancy airplanes have radar altimeters that will sound a gear up warning at 500 AGL but doesn't your GPS have a pretty darn good idea of your altitude and the terrain altitude? It would obviously be less precise but I don't know why it wouldn't be pretty straight forward. (or maybe there is a way to do this and I've never come across it).
 

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
14,217
Location
Woodinville, WA
1. The easiest way to do this is to use an open/ground contact. An open connection will look like 5V to SkyView. Grounding it will look like zero. The manual has steps for recreating this sort of a contact.
2. Yes. See page 7-70 and 7-71 in the install manual for details on these settings.
3. You sort of answered the question. It would indeed be less precise, and there are LOTS of edge conditions in which varied terrain elevations would lead to either nuisance alerts, delayed alerts, or other unexpected behaviors.
 

anthonyxritchie

I love flying!
Joined
Jun 27, 2018
Messages
2
Thanks! I guess I didn't sufficiently mess with the ranges of the gauge. It is reading 5V as it should be. I was hoping it could read the input voltage at the pin since my gear down switch is a "hot" switch, but I can always throw in a relay.

I didn't see anything about configuring speeds on 7-70 or 7-71 Or the surrounding pages. I have the "landing gear check speed" set in aircraft information. Will that automatically sync with the contact that I labeled "gear" and warn me if the gear isn't down?

As far as edge cases in a GPS driven warning, you have those with any system. Suppose I hear reports of low level wind sheer and decide to take an extra 20 kts on approach or worse yet suppose I've picked up some ice and I'm taking as much extra speed as I can possibly get on approach. Not only would my airspeed driven gear warning not go off in these cases, these are scenarios when I'm MOST likely to forget the landing gear :p The GPS could use something as simple as the elevation of your destination airport and go off when you are within 3 miles and 500ft of it (it wouldn't even need to know about the terrain). Obviously there's still plenty of scenarios that it wouldn't cover but I would still use that feature if it existed. At very least it would cover the scenarios above that the airspeed warning missed.
 

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
14,217
Location
Woodinville, WA
Make sure you're looking at the latest version of the manual. Here's the relevant excerpt from those pages:

Contacts Used for Retractable / Amphibious Landing Gear and Related Alerts
The simplest method to monitor landing gear state is to use a contact as there are only two states to monitor and it is mechanically and electrically easiest to install. To enable audio alerts related to landing gear status, the contact used for monitoring the status of landing gear must be named GEAR:
SETUP MENU > EMS SETUP > SENSOR INPUT MAPPING > C37 Pxx >
> FUNCTION: CONTACT
> SENSOR: CONTACT
> NAME: GEAR
To configure the GEAR contact alert for retractable landing gear:
Install the GEAR contact that when the landing gear is up, the state of the contact is UP and when the landing gear is down, the state of the contact is DOWN.
• SETUP MENU > AIRCRAFT INFORMATION:
> LANDING GEAR TYPE: RETRACT
> LANDING GEAR CHECK SPEED: (set as appropriate for your plane)
> LANDING GEAR OVERSPEED: (set as appropriate for your plane)
To configure the GEAR contact alert for amphibious landing gear:
• Install the GEAR contact that when the amphibious landing gear is configured for landing on water, the state of the contact is WATR and when the amphibious landing gear is configured for landing on land, the state of the contact is LAND.
• SETUP MENU > AIRCRAFT INFORMATION:
> LANDING GEAR TYPE: AMPHIB
> LANDING GEAR CHECK SPEED: (set as appropriate for your plane)
> LANDING GEAR OVERSPEED: (set as appropriate for your plane)
• SETUP MENU > SYSTEM SETUP > AUDIO SETUP > LANDING GEAR > VOICE


As for the actual annunciations, those are in the pilot's guide. Here's what you'll hear for each:

“Check Gear” : The aircraft is configured as a
Retractable gear, and the Landing
Gear is UP, and the aircraft is
descending through the configured
minimum warning speed.

“Gear Overspeed” :
The aircraft is configured as either a
retractable or amphibious gear, the
landing gear is not UP, and the
airspeed is exceeding the configured
maximum gear down speed.
 
Top