SKYMAP IIIc - terrain depiction issues

[Swiss Cheese]

Is there general awareness that this GPS unit does not actually depict terrain above 2000ft in part of the UK?

It provides a scale and colour depiction for terrain well in excess of 2,000 ft, but due to memory constraints, its software is programmed to stop terrain depiction at 2,000ft in certain mountainous parts.

Read the AAIB report re the Agusta 109 N2NR, that impacted Shanlieve mountain in the Mourne Mountains in Northern Ireland in October 2010, killing all three on board.

It seems that the Skymap IIIC did not depict the summit at 2092 ft. Given the helicopter impacted just below 2,000ft, this raises an important safety point.

There are moves afoot, arising out of the Coroner's Inquest in Belfast last week into the N2NR tragedy, for the Skymap IIIC issue to be publicised and remedied.

A major point is that there appears to be little, if any, user awareness of the real limitations of the Skymap IIIC. An AD may well be the end result, to raise awareness.

Any interested persons can PM me confidentially.

[peterh337]

The Skymap 3C is essentially same as the KMD550 MFD, and that one has for years had major issues with terrain depiction.

A chap I know in the USA who had identified several CFITs (on night IFR flights) where they impacted the terrain at heights corresponding to the terrain depiction errors.

It seems that this data comes from Jepp whose terrain data has for years been defective (http://www.peter2000.co.uk/aviation/misc/flitestar-terrain.pdf). The errors seem to come from averaging adjacent vertical values, instead of taking the highest of them :)

Obviously one has to wonder what kind of a muppet is going to use the colour coding on an MFD for ad-hoc MSA planning, but this kind of thing doesn't help.

BTW, you are an aviation crash ambulance chasing lawyer, aren't you?

[JUST-local]

Great product, I regularly use the panel mounted version the KDM150.
As part of its instillation into the aircraft it had to have VFR use only in view of the pilot.

[Swiss Cheese]

Here is a pithy quotation from the N2NR AAIB report -

"The Skymap IIIC is a supplemental aid to navigation, and the data storage in the system is limited, so the terrain mapping is a representation of only the main features and, for capacity reasons, the terrain over 2,000 ft is not modelled in the database."

The NI Coroner and Jury in Belfast were much taken by this issue last week, which is why it is now being escalated to achieve some public awareness, and hopefully an AD.

Thanks for your interest Peter337 . My interest comes from being an EC120 pilot with such a system, and with a keen interest in preventing further unnecessary fatalities by removing at least one hole in the swiss cheese.

[peterh337]

terrain over 2,000 ft is not modelled in the database
Has that been verified with a real Skymap 3C, rather than by reading the AAIB report?

It has been discontinued AFAIK but there are a fair few kicking around so it should not take somebody long to zoom the map over to Wales, or even Scotland :)

I have been told by Skyforce, Goodwood, ~10 years ago, that the 3C is identical in that respect to the KMD550 (and this is obviously visibly the case when you view the two products side by side) and the latter unit definitely does show all terrain (but shows it wrong, as I mentioned earlier).

[Mariner9]

Has that been verified with a real Skymap 3C....

Terrain >2k is certainly modelled on my Skymap IIIC

See below pic taken when passing abeam Benidorm - mountains to the North (~5K) clearly showing on unit

http://i43.tinypic.com/w8uijd.jpg

[gasax]

I've flown with a friends Skymap in Scotland and never noticed any 'height' issues.

I presently fly with a Garmin 296 and generally the height database seems pretty accurate - albeit a bloody nuisance a loty of the time - when looking out of the window clearly shopws cumulus granite.

Frankly I think the coroner's attention is entirely inappropriate - what muppet would rely upon a VFR GPS to keep the, clear of high ground?

I fly in Scotland and so perhaps am more aware of high ground than many people to the south - but frankly boring a hole in IC an depending upon a VFR un-certified GPS - it makes you a potential Darwin award winner!

[peterh337]

Terrain >2k is certainly modelled on my Skymap IIIC

Well there you are :)

frankly boring a hole in IC an depending upon a VFR un-certified GPS - it makes you a potential Darwin award winner!

I agree, but I would remove the words "VFR un-certified" :) Nobody should rely on display colour coding for obstacle clearance.

Was that heli a public transport or a military flight by any chance?

[Swiss Cheese]

Interesting information from you fellow ppruners, thanks.

The report by the AAIB was done thoroughly, and is a salutory read those of us who fly at lower levels.

If you look at Report and the graphics dealing with the Skymap IIIc, you will see the screen shot is in demo mode, but does not depict either peak in the Mournes as being above 2,000ft. Honeywell did participate in the report, and there is the comment about non-depiction of terrain due to memory capacity issues.

http://www.aaib.gov.uk/cms_resources.cfm?file=/Agusta%20A109A%20II,%20N2NR%2011-11.pdf

[gasax]

It is worth mentioning that the Skymap IIIC is an excellent piece of equipment - certainly I found it much better to use than my current Garmin 296.

But all of these gadgets are portable 'temporary' equipment and as the report correctly states are intended as 'aids'.

A far better emphasis in the report would be for the Honeywell Mk XXI Enhanced Ground Proximity Warning System (EGPWS) which was fitted to the helicopter - precisely to avoid this type of accident to have been switched on and used.

At the end of the day the Skymap is a very useful aid - the EGPWS is intended to stop aircraft flying into the ground - for it to be fitted and either not used or not serviceable, is much closer to the root cause of this accident than the Skymap.

And of course as a temporary gadget without formal certification there can be no AD on a Skymap.... as opposed to the EGPWS which is a certified addition to the aircraft.