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samkent
2009-Mar-31, 01:15 PM
Last night the tv show ďAx MenĒ left the audience hanging with a helicopter lost in a cloud bank. The scenario is they use a helicopter to lift the cut trees from a point on the mountain to another central point for loading on a truck. During the sequence of load after load, the weather moved in. As the show closed the pilot was trying to find the drop off/landing point but couldnít see anything with about 5 minutes of fuel remaining. I know the editors pumped up the drama to get us to tune in next week, but it left me wondering.

Is there any reason they canít mount a simple consumer grade hiking GPS on the dash panel?? Program the pick point and the drop off point at the beginning of the day just in case. Or would the rotors disrupt the reception too severely?

SeanF
2009-Mar-31, 01:22 PM
I don't know that the rotors would disrupt GPS reception, but heavy cloud cover can cause problems. :)

samkent
2009-Mar-31, 01:31 PM
I didn't think clouds had any effect on GPS. Wasn't that one of the selling points?

jokergirl
2009-Mar-31, 01:44 PM
GPS isn't that high resolution iirc. 2-3 metres don't make much of a difference on a road but they might if you're about to dump a log on somebody's head?

Just my 2cents.

;)

SeanF
2009-Mar-31, 01:50 PM
I didn't think clouds had any effect on GPS. Wasn't that one of the selling points?
Huh, you may be right. I remember reading that heavy cloud cover could cause problems, but that may have just been "CYA" verbiage from the manufacturer.

flynjack1
2009-Mar-31, 01:59 PM
Lots of helicopters have aviation GPS installed. The problem is that if he doesnt have GPS installed he's in trouble. The other problem would be the visability getting so low that his load hits the ground before he sees the terrain, in this case he will probably pickle (drop) the load and return to land without it. These heavy lift helicopters frequently operate with low fuel in order to be light enough to lift heavy loads, additionally they often strip all unnecessary gear off in order to save weight. Hope that didnt include their GPS.

Fazor
2009-Mar-31, 02:22 PM
Was the footage shot from inside the helicopter with the pilot? If so, it'd probably be safe to assume the bird made it back to the ground safely. I mean, they have the film, right? :)

Studioguy
2009-Mar-31, 02:29 PM
I was told by my flight instructor that any sort of map or chart on the aircraft has to be absolutely current. I don't know if that applies here, but it would seem that a cheap hiking GPS would violate that rule since the hiking/topo maps may not be perfect. Flight certified GPS systems can be expensive, compared to consumer versions.

My instructor was so insistent on the rules for maps and stuff that he saw my personal GPS in my bag and insisted that I lock it in the office so it didn't "accidentally" get onboard with us. I only had it with me because I didn't want to leave it baking in the car, so it wasn't a big deal. I'm not sure if he was just being pedantic or had a relevant gripe, but I prefer to err on the side of caution.

samkent
2009-Mar-31, 03:14 PM
GPS isn't that high resolution iirc. 2-3 metres don't make much of a difference on a road but they might if you're about to dump a log on somebody's head?

The drop off/ landing area looks to be several acres in size so 3 meters should be plenty.

On mine I can simply press one button and it remembers that spot in 3d space. Or it can remember its location every few seconds/minutes automatically. Kind of like bread crumbs in space. No map is needed. He could just follow the crumbs back to the drop off.

Yes they do strip the helicopter to save weight. I noticed the engine cowling below the rotors and several doors have been removed. But I would think the extra safety and a few extra loads would more than offset the weight penalty of a hiking GPS.

captain swoop
2009-Mar-31, 07:16 PM
Would a consumer GPS be fast enough to keep up with the helicopter?

novaderrik
2009-Mar-31, 08:20 PM
Would a consumer GPS be fast enough to keep up with the helicopter?
if he's moving around slowly and looking for a specific place to hover, then i'd think it would be better than being stuck in a thick fog bank 10 feet above the trees with no visual reference points.
but i'm sure the FAA has rules and regulations about things like this that require some super expensive equipment that needs to be calibrated often..

pantaz
2009-Mar-31, 11:21 PM
I've seen Differential GPS (DGPS (http://en.wikipedia.org/wiki/Differential_GPS)) used on large construction sites, and I think the USGS (http://www.usgs.gov/) uses it, but I don't know if it's applicable to flight operations.

flynjack1
2009-Apr-01, 12:49 AM
An aviation GPS runs about 2000-10000 dollars depending on model and some are panel installed others are temporary mounts(portable). there are other navigation aides too, but with only five minutes of gas the pilot would be planning on landing close by. Aviation charts are required for flight into instrument conditions and they must be current. They expire on 3 month intervals with updates in between. Chances are the pilot would descend through the clouds based on the GPS or divert to a airfield with a Navigation aid if within range. He might if desperate use a navaid distance/radial to go to a descent point unless visability was really low.

samkent
2009-Apr-01, 12:04 PM
Aviation charts are required for flight into instrument conditions and they must be current.

What kind of charts would be of any use? I mean they are on the side of a mountain, with no roads. I’m sure they were flying VFR and pushing it at that just to make a buck. And I’m sure the editors did their best to sensationalize the situation with careful editing. But if they had a simple hiking GPS mounted on the instrument panel the whole point would be mute. Unless there is a reason simple GPSs don’t work in a helicopter.
I doubt that consumer grade units are too slow for aircraft use. Besides when helicopters are landing they are barely moving.

flynjack1
2009-Apr-01, 02:59 PM
What kind of charts would be of any use? I mean they are on the side of a mountain, with no roads. Iím sure they were flying VFR and pushing it at that just to make a buck. And Iím sure the editors did their best to sensationalize the situation with careful editing. But if they had a simple hiking GPS mounted on the instrument panel the whole point would be mute. Unless there is a reason simple GPSs donít work in a helicopter.
I doubt that consumer grade units are too slow for aircraft use. Besides when helicopters are landing they are barely moving.

I have flown with a hiking GPS (not for purpose of air navigation, but rather to use it to identify features on the ground mountains etc). The more modern ones update fairly quickly however they can be susceptable to signal loss inside the cockpit. The older models of handheld GPS's were worse, however. With only 5 minutes of fuel the charts would be of little use since they would need to fly to an airfield to execute an approach. I am assuming they were more than 5 minutes flight away from an airfield (likely in remote mountains).

In aviation parlance we call flight in less than legal VFR conditions "scud running". "Scud running" has killed more than its share of pilots/passengers. Normal reaction to accidental entry into instrument conditions is to : a)immediately exit the conditions descend or turn 180 and fly back out of the clouds or b) climb clear of terrain and contact approach or center for a instrument clearance. With only 5 min of fuel the options are limited.

SeanF
2009-Apr-01, 04:56 PM
...the whole point would be mute.
Moot.

:)

mugaliens
2009-Apr-02, 03:58 AM
Would a consumer GPS be fast enough to keep up with the helicopter?

Yes. I've used my eTrex Legend C at speeds up to 540 kts. Works fine.

flynjack1
2009-Apr-02, 05:11 PM
Mugs, Concur, I have used a Rhino 530 Hcx in the cockpit and worked fine up to 340 kts (max speed for a slowtation).

M311
2009-Apr-03, 01:13 PM
What kind of charts would be of any use? I mean they are on the side of a mountain, with no roads. Iím sure they were flying VFR and pushing it at that just to make a buck. And Iím sure the editors did their best to sensationalize the situation with careful editing. But if they had a simple hiking GPS mounted on the instrument panel the whole point would be mute. Unless there is a reason simple GPSs donít work in a helicopter.
I doubt that consumer grade units are too slow for aircraft use. Besides when helicopters are landing they are barely moving.

But the rotor blades are moving extremely fast, not so good if you are on sloping ground or there are random objects close by and you are trying to land in dense fog.

So how did the episode continue, any way?

farmerjumperdon
2009-Apr-03, 02:11 PM
Was the footage shot from inside the helicopter with the pilot? If so, it'd probably be safe to assume the bird made it back to the ground safely. I mean, they have the film, right? :)

Way to remove all the suspense and hype the producer worked so hard to create.

Keep doing that and pretty soon all the "reality" shows become nothing more than highly scripted soap operas.