Menu Sign In Contact FAQ
Banner
Welcome to our forums

2 x IFD540 in a TB20

The advantage of two boxes is you can run as an FMS essentially and the other as a moving map.

EGTK Oxford

I know everybody thinks that but I don’t think it is quite true legally, because if you have to file an alternate, and the alternate doesn’t have a GPS approach, but needs a DME, then you have to carry a DME. I guess this isn’t common in the USA but…

Peter,

The rules are different for WAAS than for un-augmented GPS in the US. With WAAS, an alternate may be chosen that only has an RNAV approach, but the weather planning is based on the LNAV minimums. Substitution of GPS for DME or ADF is always permitted with WAAS. A significant number of approaches have a DME or ADF requirement and more ILS DME are being installed as ADF and Marker Beacons are being removed along with a reduction in the number of VOR for cross radials.

Also, last year there was a major change in the un-augmented GPS alternate requirements. It used to be that a GPS could not be used for the alternate and that included substitution for DME. The current policy is that GPS (including use for approach and substitution) may be used for the destination or the alternate, but not both. Also, if the alternate has LNAV/VNAV, one can plan on using the vertical guidance if it is provided by Baro/VNAV and not WAAS.

KUZA, United States

The US based pilot informs me that he has the approach plates in the IFD540 so he likes the larger screen for the charts on one and map with NEXRAD (airborne weather, not available outside the USA) on the other.

I would prefer to avoid the half-way measure of having one “small” GPS which is not much good for anything much beyond being a keypad / text entry interface. That’s what you get with a GTN650 / GNS430[W] and I already have this with the KLN94 which is near-useless without an MFD (KMD550) and it’s somewhat bizzare to realise that stuff dates back to the late 1990s yet even the most modern avionics don’t deliver much more for real-world IFR in Europe.

Most importantly the KLN94 cannot do LPV and if my base (EGKA, Shoreham) do LPV then I will have to seriously look at doing this.

Administrator
Shoreham EGKA, United Kingdom

A DME .. oh well :-)

Using breakers as switches?

What’s the row of 7 buttons below the transponder, each with a smaller red button below? Surely these must be circuit breakers, with the rated current readable, and the little red buttons a test facility? If so, one of them is pressed deeper than the others, suggesting that these are also used for switching the various circuits on/off. I think that is not the intended use of circuit breakers – but am curious to learn.

EBZH Kiewit, Belgium

Those are the Socata way of doing switches. Totally weird but a possible way to do it of course… Initially the TBs were without a word of English so they came up with the most creative pictograms to symbolize everything but over time they started printing English words all over the airplane.

Last Edited by achimha at 19 Oct 17:04

Below the centre stack is a row of circuit breakers used as switches.

It’s done to save space, I guess. It doesn’t cause problems in practice because they are rarely operated in flight. These are not the normal Klixon-type CBs which would not last many operations.

They have English labels.

This method has not been used elsewhere on the aircraft. There is a large CB panel on the LHS, low down.

Administrator
Shoreham EGKA, United Kingdom

Below the centre stack is a row of circuit breakers used as switches.

I think this is an ingenious arrangement. Who cares if it looks like it is taken from ST:TOS?

(Sigh, I wish I had a TB20…)

ESKC (Uppsala/Sundbro), Sweden

Using breakers as switches?

Nothing unusual. All the Switches in the Antonov 2 are breakers as well. Saves space and allows dedicated systems to “pop” in case without depowering a whole bus. Certainly preferrable to certain panels where switches and breakers both occupy a lot of space and interact often intransparently.

LSZH(work) LSZF (GA base), Switzerland

So are we saying a TB20 is a cross between a 1960s TV series and a Russian transport plane?

And while I have approach plates on the MFD, I don’t like it. IPad better for plates IMHO.

Last Edited by JasonC at 19 Oct 19:03
EGTK Oxford
Sign in to add your message

Back to Top