Wait for 5% N1 before anti coll light off?

[ManaAdaSystem]

This relates to the new (and confusing) Boeing procedures.
Shut down procedure now states:
-Set park brake.
-Seat belt sign off
-El power on
-Shut down engines
-Anti coll light off

We used to have a requirement to wait for 5% N1 (CFM 56 engines) before turning off the anti coll light. The new procedure does not mention this.

So is this 5% a left over from the old days, or something I should still practise?

Views?

[Centaurus]

Various actions were introduced by airlines to reduce the chances of ground staff moving behind a running down jet engine. Some used 25% N2, others 5% N1, others turned off the anti-collision light switch 30 seconds after closing down the engines.

None of these were specifically Boeing initiated. That is why there has never been mention of these practices in any "official" Boeing checklist procedures. These are company decisions.

[ManaAdaSystem]

Thanks,

The Company part sort of went out the window when we implemented the new procedures.
I always thought the 5% was to prevent people from getting sucked into the engine?
The question remains, is it dangerous to walk in front (or behind) an engine that has just been shut down?

[TheOddOne]

The question remains, is it dangerous to walk in front (or behind) an engine that has just been shut down?

Yes, it is.

We're now carrying out 'turnaround' audits which include observing ground handling staff applying ground power and chocks to the aircraft. If we find anyone approaching the aircraft to do either of these actions before the anti-coll is extinguished, we will interview them. It's one of our top issues.

I'm disappointed to read that this key action isn't included as a specific in some check-lists. It should be the final action, to indicate that the a/c is secure and safe to approach.

It's also dangerous to drive behind an aircraft before the engines are properly shut down.

Is the disappearance from a specific company checklist worth a CHIRPS report? (In the UK)

The Odd One

[alexban]

we use 8% N1...but no value was specified in the new or older OM from Boeing ,so it's specified by the company SOP.

[wiggy]

TheOddOne

Just a question: What are your Company procedures for handling an aircraft arriving with the APU inop?