How do you write a discrepancy and corrective action?

Write the discrepancy as the condition found: what is wrong, where, and how it was discovered, without describing the repair. Write the corrective action as what was done, the part numbers installed, the functional check performed, and the specific approved data reference (manual, chapter, and section).

What should never go in a discrepancy write-up?

The fix. A discrepancy that says "replaced worn linings" destroys the record of the condition that existed. Keep the condition in the discrepancy and the repair in the corrective action, and always check your own repair station manual for required format.

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How to Write a Discrepancy and Corrective Action That Holds Up

Joker Aviation · July 27, 2026 · 6 min read

Ask an inspector what separates a good shop from a shaky one and the answer is usually the same: the write-ups. A discrepancy and corrective action pair is the smallest unit of maintenance documentation, and it is the first thing anyone reads years later when a question comes up. Most techs were never actually taught how to write a discrepancy and corrective action. They learned by copying whoever trained them, good habits and bad.

Here is a format that works, with examples, and the mistakes that get write-ups kicked back. (As always with documentation standards, your own repair station manual and ops specs govern. If your manual prescribes a format, use it.)

The discrepancy: state the condition, not the fix

A discrepancy describes what is wrong, where, and how you know. It does not describe the repair. Keep the two jobs separate: the discrepancy is the evidence, the corrective action is the response.

A solid discrepancy answers three questions:

What is the condition? (cracked, worn beyond limits, leaking, inoperative, chafed)
Where is it, specifically? (part name, position, station or zone if applicable)
How was it found? (during scheduled inspection, reported by pilot, found during other maintenance)

Weak: "Right brake bad."

Better: "During annual inspection, right main brake linings found worn beyond limits per manufacturer maintenance manual. Right brake disc scored."

The weak version forces the reader to guess. The better version tells an inspector, a buyer, or a future mechanic exactly what condition existed and the standard it was measured against.

The corrective action: what you did, to what, per what

The corrective action states what was done, the parts involved, and the approved data you followed. Reference the specific manual and section, not just "per manufacturer's instructions."

Weak: "Fixed brake."

Better: "Removed right main brake linings and disc. Installed new linings (P/N 066-10500) and disc (P/N 164-02504). Serviced and bled right brake system. Ops and leak check satisfactory. All work performed IAW Cessna 172 Series Maintenance Manual, Chapter 32-40."

Notice what that one sentence chain carries: the action, part numbers for traceability, the functional check, and the approved data. When a parts question comes up during an audit, that P/N ties straight to the 8130-3 or cert of conformance in receiving.

Three more example pairs

Discrepancy: "Pilot reports #2 comm intermittent on transmit." Corrective action: "Found corroded coax connector at antenna base. Cleaned and reinstalled connector, performed transmit check on ground with satisfactory results IAW AC 43.13-1B, Chapter 12."
Discrepancy: "Left elevator trim tab hinge found loose during 100 hour inspection." Corrective action: "Replaced hinge attach hardware with new (hardware list on WO). Checked trim tab free play, within limits per maintenance manual Chapter 27-30."
Discrepancy: "Fuel stain observed at right wing sump area." Corrective action: "Found sump drain valve O-ring deteriorated. Replaced O-ring (P/N MS29513-011). Leak check satisfactory."

The mistakes inspectors flag most

Combining them. "Replaced worn brake linings" as the discrepancy. Now there is no record of the actual condition found.
Vague references. "IAW manufacturer's data" with no chapter. Cite the document and section.
Missing part numbers. Breaks the traceability chain that a Part 145 audit will follow.
No functional check. If the system was disturbed, say how you verified it works.
Ghost sign-offs. Corrective action written by one person, signed by another, with no inspection record in between.

Where software helps (and where it does not)

No software writes a good discrepancy for you. What it can do is stop good write-ups from getting lost. In Orion, every work order tracks discrepancies individually, each with its own corrective action and its own signature chain: the tech who did the work, the LBE sign and lock, and the CRS release, each signed with FAA AC 120-78B compliant e-signatures and sealed with a SHA-256 tamper hash. Years later, "show me the write-up" is a search, not a dig through a filing cabinet.

Try this at the morning meeting: pull one recent work order and read the discrepancies out loud with the corrective actions covered up. If the crew cannot tell what condition existed from the discrepancy alone, the write-up needs work.

Want to see discrepancy tracking with a full signature chain on a real work order? Schedule a call and we will walk one through end to end.

See Orion On Your Workflow →

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How to Write a Discrepancy and Corrective Action That Holds Up

The discrepancy: state the condition, not the fix

The corrective action: what you did, to what, per what

Three more example pairs

The mistakes inspectors flag most

Where software helps (and where it does not)

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