What are filed differences and national deviations?
A State that cannot follow an ICAO Standard tells ICAO and publishes the difference. It is a State-level record, and it is not the same thing as an exemption at one aerodrome or a stricter requirement in a tender.
Article 38 of the Chicago Convention requires a State to notify ICAO of any difference between its national regulations and practices and the International Standards. States are invited to extend that to Recommended Practices when it matters for the safety of air navigation.
The State then publishes the difference, normally in AIP GEN 1.7. India notifies and validates its differences on ICAO’s EFOD system and lists them in AIP India GEN 1.7. The FAA lists its differences in the FAA AIP.
A published difference is a State-level fact. An exemption for one aerodrome, an agreed project departure and a stricter owner requirement are different records kept in different places.
- Find the State’s AIP. Go to section GEN 1.7.
- Go to the Annex. Look under Annex 14 Volume I, and note the amendment the list covers.
- Read the entry. Note the paragraph and the details of the difference. NIL means none.
- Read the national regulation beside it. Numbering that matches the Annex does not prove there is no difference.
- Check the site and the contract. Look for exemptions, supplements and stricter owner values.
A reviewer can see which paragraphs follow the Annex and which the State has filed a difference against.
A value can match the Annex numbering yet depart from the Standard, with the departure published only in the AIP.
Keep the records apart
Only the first row is a difference in the ICAO sense. The other two are decisions about a site or a contract.
| Kind of departure | What it is | Who decides | Where it is recorded | What you do |
|---|---|---|---|---|
| Filed State difference | A departure from an ICAO Standard that the State notifies to ICAO | The State | The State’s AIP, section GEN 1.7, and ICAO’s EFOD system | Read it for every Annex your design touches |
| Aerodrome exemption or agreed departure | A regulator’s decision about one site | The regulator, with the operator | Licence, certification basis or aerodrome manual | Get it agreed and on record before relying on it |
| Stricter owner requirement | An added or tighter value in the contract | The owner or tender | Tender specification, aerodrome manual | Ask the operator which text governs on conflict |
What a published list tells you, and what it does not
GEN 1.7 is organised by Annex. Use it as the index of what a State has filed, not as the full requirement.
What it tells you
- The Annex and edition coverede.g. Vol I, Amdt 17
- The provision affectedParagraph
- The details of the differenceText
- No difference for an AnnexNIL
What it does not tell you
- The full national requirementRead the regulation
- Airport-specific proceduresAIP Supplements
- Site exemptionsLicence, basis
- Owner’s stricter valuesTender, manual
Two lists, two styles
Both lists follow the Annex order. Their content differs because each State differs. These are examples of format, not lighting requirements.
- CHECKNOW
Find the amendment your State’s list covers and compare it with the Annex amendment your design uses. Amendment 18 became applicable on 27 November 2025.
- INDIAGEN 1.7
States that the ICAO Standards and Recommended Practices are followed in India subject to differences filed from time to time. Lists differences to Standards that affect operations, facilities and services, notified on EFOD. The text reviewed covers Annex 14 Volume I up to Amendment 17.
- FAAGEN 1.7
States general conformance with Annex 14 Volume I and then lists differences, for example on runway separations and on declared distances for heliports. See the regulator matrix.
Frequently Asked Questions
Q1What is a filed difference?
A filed difference is a departure from an ICAO Standard that a State has notified to ICAO under Article 38 of the Chicago Convention, because its national regulations or practices do not match the Standard. States are also invited to notify differences from Recommended Practices when that matters for the safety of air navigation. The State then publishes the difference, normally in its AIP.
Q2Where do I find a State's differences?
In the State's AIP, section GEN 1.7, Differences from ICAO Standards, Recommended Practices and Procedures. It is organised by Annex, and an Annex with no difference is shown as NIL. India publishes its list in AIP India GEN 1.7 and the FAA publishes its list in the FAA AIP GEN 1.7.
Q3Is a filed difference the same as an exemption at one aerodrome?
No. A filed difference is a State-level departure that the State notifies to ICAO and publishes for everyone. An exemption, waiver or agreed departure at one aerodrome is a decision by the regulator about that site, recorded in the licence, certification basis or aerodrome manual. A project cannot create an ICAO difference by itself.
Q4Does a national regulation that follows Annex 14 still need a difference list?
Yes. A regulation can follow the Annex paragraph by paragraph and still depart from it somewhere. The AIP list is where those departures are published, so read the regulation and the list together. A regulation that matches the Annex numbering does not tell you whether a difference exists.
Q5What does NIL mean in GEN 1.7?
NIL means the State has no difference to notify for that Annex. ICAO guidance for the AIP asks States to list every Annex in numerical order even where there is no difference, and to give a NIL notification in that case.
Q6How current is a published difference list?
Check the amendment number the list covers. The GEN 1.7 text reviewed for India listed Annex 14 Volume I up to and including Amendment 17, while Amendment 18 became applicable on 27 November 2025. A list that covers an earlier amendment says nothing yet about the later one, so check the current AIP and the CAR or equivalent.
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