EGPWS

Question 1

What do we need to really be concerned with?

Answer 1

1) Establish the RELEVANT MSA

Look at your arrival routing and establish what you think will be good to use as the relevant MSA.

2) Justifying clearance through MSA

There are 3 reasons why we can continue descent below MSA -

A) On a publish approach procedure.
B) Under positive radar control
C) Visual

3) Position Check

Need to check QNH and verify position - (distance and baro alt) and justify continued descent. Eg. On a published approach procedure as briefed.

Question 2

Who says what?

Answer 2

PF states ‘clearance below MSA’

PM states MSA value and justifies continued descent.

Question 3

Best Practice

Answer 3

1) Starts with Effective briefing
2) How are you going to recognise descent below MSA? ……. will it be the start of the STAR when you get cleared to descend via the STAR? Will be be when you change to QNH? Will the trigger be when you reach up and press the approach button? (Like at LHR)

Then you can think about what PM will say and what will be the justification for continuing the approach? What will you do if you don’t get the position check where you expect it? Or you can’t justify continued descent?

Getting all this discussed in the briefing helps with the flow and work load later on as you can shorten responses with ‘as briefed’ because it all already been discussed.

Every time something changes , update your mental model and ask yourself is this safe and is it safe to continue. Eg radar vectors off a STAR.

Question 4

Caution

Answer 4

40 - 60 seconds before impact

Question 5

Warning

Answer 5

20 - 30 seconds before impact

Question 6

“Pop up” functionality

Answer 6

The ND will automatically display Terrain during a GPWS event if neither pilot has terrain selected. HOWEVER, if someone already has it selected, then the pop up function will NOT occur.

(The same is also true for any PWS alert and the weather radar).