SOP vs Practice: Bridging the Safety Gap AI132

The “Mess Hall” Problem: Why SOP Cannot Contain Everything

In A Few Good Men, Lt. Kaffee asks a Marine to show the written procedure to get to the mess hall.

The Marine replies: “It’s not in the book.”

Kaffee’s punchline is devastatingly simple: “You mean the whole time at Gitmo, you’ve never had a meal?”

The Marine answers: “Three squares a day, Sir.”

That exchange captures an operational truth every pilot knows: you can do the job safely every day even when the manual doesn’t describe every micro-step.

Not because SOP is irrelevant—but because practice, technique, and culture fill the gap between written procedure and real-world execution.

That gap matters directly in AI132.

SOP vs Practice in Aviation: The Real Difference

What is an SOP?

A Standard Operating Procedure (SOP) is the documented minimum: the standardised, trained, audited sequence for a repetitive task. SOPs reduce ambiguity, improve consistency, and help organisations demonstrate regulatory compliance.

What is practice?

A practice is the “how” that makes SOP work in the cockpit:

• the tactile method of moving a switch,
• the discipline of hands-off unless required,
• the habit of verifying detents/guards,
• the micro-pauses that prevent accidental inputs.

Practice may be unwritten, but it is not optional. It is often the difference between a control being moved correctly and being moved accidentally.

AI132: The Detail That Changes the Whole Safety Conversation

In the AI132 narrative, the crew reportedly observed that the fuel control switch did not remain positively latched in RUN when “slight vertical pressure” was applied, but latched correctly on a subsequent attempt. The flight continued without incident.

Then the discussion shifts toward force direction. The switch is secure when force is applied parallel to the base plate, but can move when external force is applied in an incorrect direction. A circulating video is referenced as showing “incorrect procedure.”

Here is the safety-critical mismatch:

• Pilot report:slight vertical pressure
• Technical explanation offered: force vector / axial-direction handling narrative

That mismatch is not a “small wording issue.” It is the kind of mismatch that, if not resolved, produces premature closure—a classic human factors trap where the system decides what must have happened before proving what actually happened.

The Two Questions That Must Be Answered (And Haven’t Been Explained Away)

If the explanation is simply “incorrect direction force,” then two obvious questions follow:

1) Why didn’t it happen on the right Fuel Control Switch?

Both switches sit in the same cockpit, used by the same crew, in the same environment. If the hazard is purely “handling technique,” why is it left-specific?

2) Why didn’t it happen every time the engine is started?

If “slight pressure” can unseat the switch, why do we not see this regularly—on every start, on every sector, across fleets?

These are not rhetorical questions. They are investigation-quality questions that separate:

• a single anecdote + narrative, from
• a repeatable failure mechanism.

What Could Explain “Left Only” and “Not Repeatable”? (Without Blame and Without Denial)

Several non-mutually-exclusive possibilities exist. A serious safety analysis holds them open until evidence closes them.

A) Hardware asymmetry is normal in real life

Left and right switches may share the same design but not the same life history:

• micro-wear differences,
• detent spring fatigue variation,
• tolerance stack effects,
• contamination, friction, or subtle internal wear.

That can produce rare, side-specific behaviour even when both switches are “within limits.”

B) Humans describe force vectors poorly—especially during routine tasks

A pilot may honestly experience a push as “vertical,” while the actual applied force includes a lateral component due to:

• wrist angle,
• reach posture,
• fingertip placement,
• incidental contact (knuckle/sleeve),
• guard/switch geometry.

This is not “pilot blame.” It’s basic ergonomics: humans are unreliable vector sensors.

C) It may require two conditions at once

A marginal tolerance condition plus a particular load direction plus a specific posture/distraction window can produce a rare event:

• not repeatable on demand,
• not seen on the right switch,
• not seen on every start.

That pattern—rare, context-dependent, hard to replicate—is common in safety occurrences.

D) The second attempt latched correctly—this itself is diagnostic

The fact that it latched on re-attempt can fit:

• partial engagement the first time,
• transient sticking/friction,
• different force vector on the second attempt,
• or a subtle “seat the detent” effect.

What a Robust AI132-Quality Investigation Should Do Next

If safety learning is the goal, the investigation should explicitly test the left-right mismatch and the repeatability question, for example:

1. Measure detent/latch force profile left vs right (force gauge across travel).
2. Bench test + teardown for wear, burrs, spring condition, latch-face polishing, contamination.
3. Installation and panel interface checks (alignment, interference, torque effects, guard fit).
4. Ergonomic replication (seat position, reach, hand path) to see whether “vertical pressure” can generate a lateral component in that cockpit geometry.
5. Trend analysis (previous write-ups, repeated removals, fleet reliability signals).
6. Treat any “video evidence” as context, not proof of what this crew did.

Until these steps are addressed transparently, shifting quickly to “incorrect technique” risks becoming a narrative closure rather than a demonstrated causal chain.

Because as an immediate barrier, “operate strictly as intended” is a controllable safety action—especially if: the switch is serviceable, but vulnerable to non-design-direction loads, and there is evidence that incorrect handling practices may be circulating.

Because as an immediate barrier, “operate strictly as intended” is a controllable safety action—especially if:

• the switch is serviceable,
• but vulnerable to non-design-direction loads,
• and there is evidence that incorrect handling practices may be circulating.

However, there is a better way to phrase such a safety message:

Instead of sounding like “the SOP is everything”, it should acknowledge the SOP–practice gap and focus on control-handling discipline:

• “hands off unless required,”
• deliberate pull-to-unlock technique,
• verification of positive latch,
• and a micro-pause when something feels abnormal.

That keeps the message safety-centred, not crew-targeted.

What to Remember (Cockpit Takeaways)

SOP is the floor. Practice is the margin.
And when something unusual happens—as in AI132—the correct safety response is not only “follow SOP,” but:

• Investigate the mismatch
• Quantify the mechanism
• Avoid premature pilot-error closure
• Standardise technique without erasing legitimate defect possibilities

Several non-mutually-exclusive possibilities exist. A serious safety analysis holds them open until evidence closes them.

• SOP is necessary but never sufficient for every tactile nuance.
• Left-right differences matter; don’t dismiss side-specific behaviour.
• Non-repeatable events still deserve rigorous analysis.
• When rushed or distracted: Stop–Reset–Re-verify (a simple human factors escape route).
• Safety culture improves when we ask: “What made this easy to do?” not only “Who did what?”

Conclusion

AI132 is not a debate about whether SOP matters; it is a reminder of what SOP cannot capture. The pilot’s observation of a “slight vertical pressure” outcome and the later explanation framed around a specific force direction are not automatically the same thing.

The mature safety posture is simple: reinforce correct control-handling technique as an immediate barrier, but keep the engineering question open until evidence explains why the effect appeared on one switch, in one moment, and not routinely.

However, there is a better way to phrase such a safety message: Instead of sounding like “the SOP is everything”, it should acknowledge the SOP–practice gap and focus on control-handling discipline: “hands off unless required,” deliberate pull-to-unlock technique, verification of positive latch, and a micro-pause when something feels abnormal.