GPS Problem

[Carrier]

I have flown aircraft owned by three separate operators in Africa and have been a right seat passenger in aircraft owned by three other operators. All these aircraft have a panel mounted Garmin GPS 100. This non-moving map GPS was one of the first units on the market. Its advent must have been very welcome in an area of widely separated VORs and NDBs, which sometimes do not operate anyway! The early to market popularity of the Garmin GPS 100 would explain why there are so many of these units still in use. This GPS still does an excellent job except for one problem. The display is often unreadable, particularly if one is wearing sunglasses.
Many of my flights are eastbound in the early morning and westbound in the late afternoon, straight into the sun. Good sunglasses are needed and it is almost impossible to read the GPS. It is made worse by the units all being mounted in the centre stack so that the white shirt of the right seat occupant reflects off the glass front of the GPS display. Perhaps Garmin only tested the GPS 100 in the perpetual gloom of the Pacific Northwest!
There is no problem with reading all the other instruments with their clearly visible white numbers and needles. I am surprised that the GPS 100 was released with this weak display but it presumably sold well because of the obvious benefits of a GPS as against no GPS.
My only experience of a recent GPS unit was with a friend who uses a GPS 111 Pilot on top of the glareshield in addition to his panel mounted GPS 100. The Pilot did not seem to be any more readable. Do all modern portable GPS units still have this poor readability problem? If there are any which can be read as easily as the analogue gauges please let me know. I would like to obtain a portable GPS for aviation back-up and for land and marine use. I do not see the readability being a problem on land or in a boat but as it will have plenty of use in the air I do want to get one that can be easily read in a plane while wearing sunglasses.
Because of my experience with GPS poor readability I would be interested in knowing if so-called glass cockpit displays have the same readability problem, particularly if one is wearing sunglasses.

[George Tower]

I seem to recall reading that this was a problem in glass cockpits when wearing polarised sunglasses, so it would be interesting to know if your sunglasses are polarised.

[Stephen Stark]

Carrier

I have had some good experience with sunglasses and the Pilot III GPS from Garmin - it is either a handheld, or it can be dash mounted with the use of a bracket. It can also use the aircraft's power supply if it is a permanent fixture, and if angled right it seems good. Despite that I have heard the same with certain sunglasses, so good luck in finding one!

S

[172-Captain]

Nothing is readable when the sun is shining straight on it.

With regards to portable Garmin: (I am not sure about the others)

Colour screens are the most "readable" in bad light but are often bulky. Traditional LCD screens have three times more battery life and are cheaper to purchase. All the units can plug into your aircraft should it have a cigarette socket.

Panel mount colour moving map GPS screen: the best - we all want one. (Just can't flight plan the lazy way at home!)

Cheers
MB

[gate5]

Carrier
I think George Tower is correct in what he is saying- the problem lies with the type of sunglasses you are wearing. I personally experienced this the other day when a salesman in a sportsshop demonstrated this to me. The titanium lenses which are now available with some types of sunglasses ( to name the make I tried- Oakley) seem to take care of the problem- obviously at a price. ( +- R2000-00)Try them out & see if it does the trick for you.
Let me know what you think.

[George Tower]

Here's a good thread regarding the polarised/non-polarised issue.

http://www.pprune.org/forums/showthread.php?s=&threadid=21605&highlight=sunglasses

Gate5,

I'm sure Oakleys are the best glasses for flying.....they're great for cricket but after 3-4 hours with a headset I find they really hurt....may be it's these flying club Bronze-Age headsets that cause the problem:cool:

[Snoop]

I use non-polarised ray bans and a yoke mounted garmin GPS 196 and an old peltor headset for aerial photography work in the UK. There is also a glareshield mounted Garmin GPS III pilot in the Aircraft I fly. Due to the work, we only fly when it is nice and sunny and then average around 6-7 hours airborne.

The pilot III seems to be a good receiver but the display is tiny and pretty useless in southern England with all the airspace it tries to portray especially when in sunlight. I find the size of display on the 196 and the fact it is lower in the aircraft means that in sunlight it is a lot easier to read.

Don't have any probs with the headset and the ray bans over 7 hours. I guess the key is choosing sunglasses with thin arms and good earpiece cushioning.

[Carrier]

Thanks for the replies. I do not think my clip-on sunglasses are the problem. They are not polarised and were selected as being suitable for flying. I have been using them for flying for nearly three years in numerous aircraft without a GPS.
I have had no problems with reading any of the gauges or instruments until this past year when I started flying aircraft equipped with the Garmin GPS 100. I will say that this GPS is quite readable if the sun is shining directly on it. It also works very well at night when the adjustable brightness enables it to be adjusted to match the light level of the other instruments. However, in bright daytime conditions with very high glare from the haze it simply does not have enough contrast and brightness to be easily readable. All the other instruments are easily read, it is just the GPS 100 that is not. I have had this problem with units in several planes so it is not just one faulty unit that is difficult to read.
I have fiddled with the contrast adjustment and backlighting but am unable to make it easily read in the daytime. In fact, even without sunglasses it is difficult to read it against strong light. I tried adjusting one in the hangar a couple of days ago. The plane was facing the open doors and with the bright light streaming in it was difficult to read the panel mounted GPS 100. A mechanic was working inside the plane when I attempted to adjust the contrast. He noticed how difficult it was to read the GPS.
Last week I was flying towards the sun in the late afternoon. The GPS was almost unreadable so it was easier to do most of the trip tracking a VOR radial outbound and then using the heading indicator for the last forty minutes. On this route ATC sometimes asks what radial I am on from another VOR and my distance. I had the GPS set up for this, so when asked I pressed the button. I was unable to read the bearing and range until I removed my sunglasses and ducked my head down below the glareshield! I had another pilot in the right seat that day who also noticed and commented later on how difficult it was to read the GPS. The problem is not peculiar to me. Anyway, we are not going to change the GPS 100 but this sort of thing should not be necessary with newer equipment.
I am not knocking the GPS 100. It is great to have a GPS as against not having one. I am sure that the makers did their best with the technology available at the time but years have passed and technology should have improved by now. Ideally I would like to borrow or rent for a few days some examples, such as the Garmin 196 and 296 and the Lowrance Airmap 500 and 1000, and see how readable they are. I expect their other functions all work as it says on the boxes. However, it is not possible to try them like this and I do not feel like putting out over US$500 to mail order one with a chance that I might receive a product that is difficult to read in the conditions in which I do most of my flying.
I made the original post to try and find out if this readability problem has been overcome with current handheld GPS offerings and threw in the query on glass cockpit displays as in the future I expect to be using one.

Regarding sunglasses, there was an excellent thread three or four years ago on PPRuNe. This dealt with all the options, including for those who need corrective lenses. My eye doc and I were both aware of all this when we selected my current clip-ons. The general opinion on this thread seemed to be that the best for aviation were the top down gradient type from Hidalgo of Texas and then the Serengeti sunglasses with photo-adjusting lenses. I actually contacted Hidalgo and obtained a catalogue but when I went to place an order a few months later he had closed the business, apparently because of ill health. Perhaps he has recovered and reopened the business or perhaps someone else has taken it over?