What does it mean "Below the line" whenver doing checklists?

[Trung Hoang]

I am learning to fly an airlines, specifically the Aerosoft Airbus and it has the checklists voice feature. Sometimes I hear below the line but I do not understand. What is that? Thank you.

Extra question: What should I definitely need to know about checklists in airliners? Any interesting findings? 

[Alex Noble]

To the line, and below the line, refers to a checklist being split into two parts. AFAIK checklists generally can't be partially completed due to the potential of then missing items, so these allow a checklist to be treated as two checklists.

As an example, on a before takeoff checklist there are items you can do whilst holding short, but some which would you'd only do once on the runway - setting lights etc, so the checklist could be split into two so that minimal actions need to be checked once lining up.

[Martin Loxbo]

As Alex said, the line is just a way to separate different parts of the checklist. For example, in my airline (B738) we have a line on the "Before start checklist". We continue "below the line" when cleared for startup/pushback. On the "Before takeoff checklist" we hold at the line until we are cleared to line up on the runway, and then the captain calls "below the line", both captain and F/O complete their line up actions (turning on strobe and landing lights, TCAS etc), and then the checklist is completed below the line.

 

7 minutes ago, Trung Hoang said:

Extra question: What should I definitely need to know about checklists in airliners? Any interesting findings? 

There are different checklist philosophies. Some (probably most) checklists are so called "challenge and response", which means one pilot (usually PF) calls for the checklist, the other pilot (usually PM) reads the checklist "challenge" and then the first pilot responds (for example, first pilot reads "Generators", second pilot looks at the generator indications and replies "ON"). Other checklists may be done silently by a single pilot, and yet other checklists can be done as "challenge, response, and repeat response". Usually this is for non-normal checklists or checklist that are not routinely done. In this case the pilot reading the checklist will read the challenge and the expected response, for example "Generators - ON". Then the other pilot will reply with the response, i.e. "ON".

Probably the most important aspect though is to read any checklist diligently and carefully, even though you've done it hundreds or thousands of times before! It's very easy to fall into the trap of "rhyming responses" where you say what you expect to see rather than actually checking. This has lead to many incidents such as not setting takeoff flaps, not configuring the pressurization system properly, or even forgetting to shut down the engines when parked on stand!

 

[Lauri Uusitalo]

Better not to learn "below the line" concept too much as Airbus has now changed the standard checklists and removed this concept.

Edited January 30, 2022 at 11:34 AM by Lauri Uusitalo

[Trung Hoang]

12 hours ago, Martin Loxbo said:

As Alex said, the line is just a way to separate different parts of the checklist. For example, in my airline (B738) we have a line on the "Before start checklist". We continue "below the line" when cleared for startup/pushback. On the "Before takeoff checklist" we hold at the line until we are cleared to line up on the runway, and then the captain calls "below the line", both captain and F/O complete their line up actions (turning on strobe and landing lights, TCAS etc), and then the checklist is completed below the line.

 

There are different checklist philosophies. Some (probably most) checklists are so called "challenge and response", which means one pilot (usually PF) calls for the checklist, the other pilot (usually PM) reads the checklist "challenge" and then the first pilot responds (for example, first pilot reads "Generators", second pilot looks at the generator indications and replies "ON"). Other checklists may be done silently by a single pilot, and yet other checklists can be done as "challenge, response, and repeat response". Usually this is for non-normal checklists or checklist that are not routinely done. In this case the pilot reading the checklist will read the challenge and the expected response, for example "Generators - ON". Then the other pilot will reply with the response, i.e. "ON".

Probably the most important aspect though is to read any checklist diligently and carefully, even though you've done it hundreds or thousands of times before! It's very easy to fall into the trap of "rhyming responses" where you say what you expect to see rather than actually checking. This has lead to many incidents such as not setting takeoff flaps, not configuring the pressurization system properly, or even forgetting to shut down the engines when parked on stand!

 

Oh thank you for the detail response!

 

12 hours ago, Alex Noble said:

To the line, and below the line, refers to a checklist being split into two parts. AFAIK checklists generally can't be partially completed due to the potential of then missing items, so these allow a checklist to be treated as two checklists.

As an example, on a before takeoff checklist there are items you can do whilst holding short, but some which would you'd only do once on the runway - setting lights etc, so the checklist could be split into two so that minimal actions need to be checked once lining up.

Very straight forward, thanks!

12 hours ago, Lauri Uusitalo said:

Better not to learn "below the line" concept too much as Airbus has now changed the standard checklists and removed this concept.

So how do they change it? I wonder

[Bernardo Reis]

4 minutes ago, Trung Hoang said:

So how do they change it? I wonder

They renamed and implemented new checklists. Take for example the "BEFORE TAKEOFF CHECKLIST", it will be replaced by "TAXI CHECKLIST" - basically the items "to the line" that were done whilst taxiing - and by "LINE UP CHECKLIST" - the items "below the line" that you would do when lining up.

[Kirk Christie]

It's also important to note that a check list is not a to do list, there are some out there that are more of a list of flows than a check list.

Flows should be memory items, these are completed then a check list follows to ensure the crucial items have been done, a check list typically does not include everything that gets done at each phase of the flight.