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## Route segment LSALT or GRID LSALT

• Posts: 109

### Jase88 created the topic: Route segment LSALT or GRID LSALT

Hey Bob and Co,

When asked a question about the alternate minima for a day IFR flight to an aerodrome without an IAP, I understand the minima is LSALT +500 feet and 8km Viz. How will I know whether to use the grid LSALT or the route segment LSALT?

Thanks

• Posts: 2469

### bobtait replied the topic: Route segment LSALT or GRID LSALT

Both th route LSALT and GRID LSALT are valid for this purpose. Use the one that gives you the most advantage.

• Posts: 109

### Jase88 replied the topic: Route segment LSALT or GRID LSALT

Thanks.

But with this question if i was able to use the grid LSALT it would be 3000 + 500 meaning that i wouldn't require an alternate. Innisfail is just inside the grid that has 3000ft.

• Posts: 140

### Bosi72 replied the topic: Route segment LSALT or GRID LSALT

Innisfail isn't an aerodrome without IAP.

• Posts: 109

### Jase88 replied the topic: Route segment LSALT or GRID LSALT

The images i attached explains further.

The question states that there is currently no IAP that can be flown as the NDB is unserviceable and you aren't current on GNSS.

• Posts: 140

### Bosi72 replied the topic: Route segment LSALT or GRID LSALT

Read the last sentence in AIP GEN 3.3-6, Para 4.1

• Posts: 109

### Jase88 replied the topic: Route segment LSALT or GRID LSALT

Ok so it says, "the highest grid LSALT must be used".

So does this mean use the higher of the sector LSALT and the grid LSALT?

I'm going to need a lot more clarification here as to what each one of these is for. I'm more confused than when i started haha!

• Posts: 140

### Bosi72 replied the topic: Route segment LSALT or GRID LSALT

Be realistic. You have some very high mountain peaks to the North, along your route from Cairns, which has 6700ft as lsalt. All Innisfail approach plates have mda at 6500ft.

It is by pure coincidence that Innisfail is on the other side of grid border (by 1nm) where lsalt is 3000ft.

I would use grid only when flying, as pulling rulers, protractors and calculating lsalt whilst in-flight isn't wise decision. The first 3 words in the question says "you are planning".

Hope above helps.
The following user(s) said Thank You: Jase88

• Posts: 109