Signature tracking and signing history, built in.
Every sign-off in MRO Tracker is made by a named person on their own login and stored with the record, role, date and time. Signed records lock, and every later change keeps its approver and reason.
That lines up with the FAA's standard for electronic signatures and records, AC 120-78B.
What the FAA expects of an electronic signature
The signature itself is required by 43.9 and 43.11, and 91.417, 135.439 and 145.219 set how long the records are kept. AC 120-78B (December 11, 2024) describes an acceptable way to do it electronically. It is guidance, not a rule.
- Unique and authenticated. The signature belongs to one identified person, under their sole control.
- Clear intent. A statement such as "Signed by", shown after the signer reviews the record.
- Tied to the record. The signer cannot deny it, and a signed record cannot change.
- Corrections re-signed. A correction needs a new signature and supersedes the old one.
- A sound system. Controlled access, backup, records kept unaltered and produced for the FAA on request.
How MRO Tracker records a signature
- Who. Each user signs in with their own account, with MFA or single sign-on and password rules set per group.
- How. Drawn, PIN or biometric signatures, confirmed at signing, with location recorded when the device allows.
- In what role. One to five signature levels per record: mechanic, inspector, RII and return to service. An RII is signed by an inspector who is not the mechanic.
- On what. Task cards, work orders, MEL deferrals, discrepancies and return to service; in Flight Ops, releases, FRAT, load manifests and fitness for duty.
- Logbook wording. Finished work prints as a logbook entry with 43.9 or 43.11 wording.
Signing history and audit trail
- Signed records lock. Changing a signed entry needs an approver and a reason, and both are kept on the record.
- Tamper evidence. Release, FRAT and weight and balance sign-offs are stored with a SHA-256 hash in an append-only log.
- Admin audit log. Role changes, invitations, imports, overrides and settings are logged, along with each user's login history.
- For the inspector. Export records to CSV or PDF at any time, and give auditors free view-only seats.
AC 120-78B, point by point
| AC 120-78B point | Paragraph | How MRO Tracker meets it |
|---|---|---|
| Unique to the signer | 2.2.1 | Own login per user; drawn, PIN or biometric signature |
| Signer identified and authenticated | 2.1.2.2, 2.2.6.1 | MFA or SAML single sign-on; PIN or biometric confirmation at signing |
| Intent to sign shown first | 2.2.2 | Signing statement stored on flight sign-offs; role named on maintenance sign-offs |
| Signer reviews the record first | 2.2.4.1 | Signature applied on the open record |
| Signature tied to the record | 2.2.5 | Stored with the record, role, date and time; SHA-256 hash on flight sign-offs |
| Signed record can't be changed | 2.2.7 | Signed records lock; edits need an approver and a reason |
| Correction supersedes the old signature | 2.2.8 | Approved change and reason kept on the record |
| Controlled access, records preserved, backup | 3.2.1 to 3.2.7 | Row-level security per group, roles, audit log, hosted database |
| Records produced for the FAA or NTSB | 3.2.8.6 | CSV or PDF export; free auditor seats |
Source: FAA AC 120-78B. A summary for planning, not legal advice.
What to do on your side
Write your policy
Describe who signs what, the roles and how corrections are made in your manual (AC 2.2.11, 3.2.8). We can help you draft it.
Talk to your FSDO
Part 91K, 121, 125, 135 and 145 certificate holders use OpSpec A025 for electronic signature and recordkeeping systems.
Train your team
Show everyone how to sign and correct records, and keep the training records (AC 3.2.9).
AC 43-9D and AC 120-78B: digital maintenance records
The FAA has replaced both of its main guidance documents on maintenance records. AC 43-9D (September 2025) recognizes electronic maintenance records and brings Form 8130-3 return-to-service guidance into one place; AC 120-78B sets out what an acceptable electronic signature and records system looks like. Our 3-page brief covers what changed, what didn't, the paragraphs that matter, and a checklist for going paperless under OpSpec A025.
See signing and history on your own aircraft
A 20-minute walkthrough, or start a free 14-day trial. Want it in writing? Download the signature brief or the records brief.