AAIB(H) UK October 2023

[Luther Sebastian]

Hoist hook falls off AW169 during pre-start, a possible victim of ‘procedural drift’ - link (it’s in inverted commas only because I have never heard of the term)

Record onlies include loss of a cowling on a 355F2 in flight because of distraction during the preflight, a Rotorway Exec feeling uncomfortable about a fuel divert to Duxford because of a busy air show and finally running out a couple of miles short of the next alternative, and fixed-wing G-SNOG only because I’d love to make radio calls with that reg.

[[email protected]]

The old military term would be 'switch-pigs' when you hit a button you weren't supposed to or hit the right button at the wrong time - very embarrassing to pickle off the winch hook..........

[212man]

Originally Posted by [email protected]

The old military term would be 'switch-pigs' when you hit a button you weren't supposed to or hit the right button at the wrong time - very embarrassing to pickle off the winch hook..........

Not quite the same. Procedural drift is when SOP start to be amended by crews over time - either deliberately or otherwise - resulting in potential errors. e,g :

The crew could not explain their exact sequence of cut switch guard raises, why the hoist power was applied out of sequence or why the hoist operations pre-start procedure in the company checklist was not followed in order

[ericferret]

Originally Posted by Luther Sebastian

Hoist hook falls off AW169 during pre-start, a possible victim of ‘procedural drift’ - link (it’s in inverted commas only because I have never heard of the term)

Record onlies include loss of a cowling on a 355F2 in flight because of distraction during the preflight, a Rotorway Exec feeling uncomfortable about a fuel divert to Duxford because of a busy air show and finally running out a couple of miles short of the next alternative, and fixed-wing G-SNOG only because I’d love to make radio calls with that reg.

G-SNOG,

Reminds me of the arrival of Willie Carson the jockey at the old Doncaster airport in G-WILI.

"Where do you want me to park?"

Linda in ops, "Next to G-PUSY but not too close."

[212man]

fixed-wing G-SNOG

​​​​​​​I see the type is a actually a Kiss 400!

[[email protected]]

Not quite the same. Procedural drift is when SOP start to be amended by crews over time - either deliberately or otherwise - resulting in potential errors. e,g :

yes, when you are so used to doing something every sortie, like a hoist check, you can over-anticipate the other persons actions since it is an exchange of verbal confirmations and requests combined with a set of physical actions. The you get the switch pigs because one person is mixing the words and actions - usually accidentally.

​​​​​​​I can't imagine they actually do the hoist check from a check list.

[212man]

Originally Posted by [email protected]

yes, when you are so used to doing something every sortie, like a hoist check, you can over-anticipate the other persons actions since it is an exchange of verbal confirmations and requests combined with a set of physical actions. The you get the switch pigs because one person is mixing the words and actions - usually accidentally.

I can't imagine they actually do the hoist check from a check list.

There was interesting case, not the same but with parallels to procedural drift, with BA38. BA had taken the emergency shutdown checks and split them Left and Right onto placards on the pilots' yokes, to show their respective actions. Unfortunately, if done out of sequence, which they were, some actions were no longer possible (I think it was the fuel valves being closed that didn't work). Seemed like a good idea at the time, but subsequently proved it was best to leave it as Boeing had published it!

[Droopy]

Not the first time an interrupted inspection has resulted in a sub-optimal situation https://www.gov.uk/aaib-reports/aero...6-january-1993
As I recall the tail assembly was displayed with JC's comment "this might hurt" Mightygem might confirm?