An AAI NOC is valid for 8 years from the date of issue and can be extended to a maximum of 12 years from issue under Rule 9A. Revalidation is not automatic: it needs construction to have started and a request made in time. For the full process, see our guide to AAI NOC for height clearance in India.
Quick Answer
- Validity: 8 years from the date of issue.
- Maximum life: 12 years from the date of issue, under Rule 9A of the Height Restrictions Rules (GSR 770(E), 17 December 2020).
- Revalidation: one time, without fresh assessment, if construction has started, the request is made within the validity period, and the delay was beyond the developer’s control.
- If construction never started: the validity is not extended, and you must apply for a fresh NOC, with the height reassessed.
Validity at a Glance
| Item | Rule |
|---|---|
| Initial validity | 8 years from the date of issue |
| Maximum extension | Up to 12 years from the date of issue (Rule 9A) |
| Revalidation | One time, within the validity period |
| Condition | Construction has commenced, and the delay was beyond the developer’s control |
| Form | Undertaking 1C, filed with the revalidation application |
| Where to apply | Online on NOCAS, for NOCs issued through NOCAS |
| If not eligible | Fresh NOC, height reassessed |
AAI’s own NOC letters carry the same wording: valid for 8 years, with one-time revalidation without assessment if construction has started and the request is made within the validity period.
How Validity Is Counted
Validity runs from the date of issue on the NOC letter, not from the date you applied or started work.
| Example (illustrative) | Date |
|---|---|
| NOC issued | 15 March 2020 |
| Valid until (8 years) | 14 March 2028 |
| Latest possible end after extension (12 years) | 14 March 2032 |
Revalidation does not restart the clock. The maximum is counted from the original issue date.
8 Years or 12 Years? Clearing the Confusion
You will see both numbers online, and both come from real rules at different times.
- Older AAI guidelines (2014): initial validity was 5 years for buildings and 7 years for chimneys, lines and masts, with total revalidated periods of up to 8 years for buildings and 12 years for masts, chimneys and lines.
- Rule 9A (2020): an NOC issued under rule 5 is valid for 8 years and can be extended to a maximum of 12 years from issue. The rule does not distinguish structure types.
- Older NOCs: a 2023 amendment (GSR 877(E)) is reported to deal with NOCs issued before the 2015 Rules. If you hold one, check that notification.
So “12 years” is the maximum, not the starting validity. For the legal background, see GSR 751(E) airport NOC rules.
When You Can Get Revalidation
All of these should be true:
- Construction has commenced. Work is in progress or completed to a stated level.
- The request is made within the validity period. Applying after expiry is too late.
- The delay was beyond the developer’s control. AAI’s text gives no list of examples, so keep documents that explain the delay.
- You are not asking for more height. Revalidation keeps the granted height. A higher height needs a review or appeal.
When You Cannot
- Construction never started. The NOC will not be extended, and a fresh application is needed.
- The NOC has expired. A new NOC is needed.
- You already used the one-time revalidation. There is no second one.
- You want to change the height. Use a review or appeal instead. See our AAI NOC appeal guide.
If the height was granted after an aeronautical study, AAI’s guidelines say revalidation is processed at AAI headquarters, not the regional office.
The Revalidation Process, Step by Step
- Check the dates. Note the issue date and the validity end date. Aim to apply well before expiry.
- Confirm eligibility. Construction must have commenced, and you need a reason for the delay.
- Prepare the undertaking. Undertaking 1C states that construction is in progress or completed and records the level reached.
- Gather evidence. Collect a commencement approval, site photographs and delay records. This is good practice, not a listed requirement.
- File online on NOCAS. Use the dashboard option for revalidation against your NOC ID. See the NOCAS portal application process.
- Track the file and respond to queries. Keep the revalidation letter with your project records.
We found no published decision timeline or fee for revalidation in the sources reviewed, so confirm both on NOCAS. The details of AAI’s revalidation circular, ADSAC 02 of 2023 (issued 21 December 2023), are listed on the NOCAS circulars page.
Documents for Revalidation
| Document | Notes |
|---|---|
| Copy of the valid NOC | With NOC ID and letter number |
| Undertaking 1C | Construction status and level reached |
| Authorisation letter | If an agent or consultant files for the owner |
| Proof of commencement | Good practice: approval, photographs, progress record |
| Explanation of delay | Good practice: documents showing it was beyond your control |
For the general paperwork, see documents required for airport height clearance NOC and NOCAS application documentation.
Revalidation, Review, Appeal or Fresh NOC?
| Route | Use when | Height changes? |
|---|---|---|
| Revalidation | Construction started, NOC nearing expiry | No |
| Review | You got less height than requested, or want more | Possible |
| Appeal | You disagree with the granted height | Possible |
| Fresh NOC | Expired, or construction never started | Reassessed |
Corrections to survey data are a separate matter. See wrong coordinates NOC rejected and AAI NOC objection reply.
What Happens If the NOC Expires
If you apply afresh, the permissible height is reassessed under the rules and aerodrome data in force at that time. That can differ from your earlier NOC. In a reported Bombay High Court case, AAI argued that a lapsed NOC must be reassessed under current rules. The court’s view turned on that case’s facts, so do not count on one outcome. We cover the case in our AAI NOC appeal article.
Practical points:
- Do not build above your old NOC’s height while a fresh application is pending.
- Run a new survey. See our guide to RTK-GNSS vs traditional GPS survey accuracy.
- Check your plot with the 5-minute AAI NOC required checklist.
Sale, Transfer and Design Changes
- Sale or lease: the NOC is deemed transferred to the new owner or lessee, who is bound by its conditions. The validity does not restart.
- Higher floors or revised design: revalidation will not add height. Use a review, appeal or fresh application, and update your survey if needed.
- Defence airfields: an AAI NOC does not cover a separate defence NOC. See the defence NOC or AAI NOC flowchart.
Structure-Specific Notes
Rule 9A applies to NOCs issued under rule 5, so it covers buildings, mobile towers, transmission towers, solar projects and wind turbines. Large projects with long build times should plan the revalidation window at the start.
Mistakes to Avoid
- Applying after the NOC has expired
- Assuming 12 years is the initial validity
- Assuming revalidation adds height
- Filing without an undertaking on construction status
- Losing track of the issue date on long projects
- Treating a revalidation as a new approval for a changed design
- Not checking the original NOC’s conditions and survey data
Project Calendar Tip
Add three reminders to your project plan: the NOC expiry date, 12 months before expiry for a status check, and 6 months before expiry for filing any revalidation. Also check the AAI NOC approval timeline so you know how long first-time approval took.
Frequently Asked Questions
How long is an AAI NOC valid?
8 years from the date of issue.
Can an AAI NOC be extended beyond 8 years?
Yes, up to a maximum of 12 years from issue under Rule 9A. AAI’s NOC letters allow one-time revalidation without assessment if construction has commenced and the request is made within the validity period.
How many times can I revalidate?
Once.
What if construction has not started within 8 years?
The validity is not extended. You must apply for a fresh NOC, and the height is reassessed.
Can I increase the height during revalidation?
No. Revalidation keeps the granted height. Use a review, appeal or a fresh application for a different height.
Until when can I apply for revalidation?
Within the validity period of the NOC. Apply well before it ends.
Is there a fee for revalidation?
We found no published fee in the sources reviewed. Confirm on NOCAS before filing.
Does the NOC transfer if I sell the plot?
Yes. It is deemed transferred to the new owner or lessee, who is bound by its conditions.
Does the 12-year limit apply only to masts and towers?
No. Rule 9A applies to NOCs issued under rule 5, regardless of structure type. Older guidelines treated buildings and masts differently.
Need Help With Your NOC Timeline?
Send us your NOC letter, and we will check its dates, conditions and survey data, and tell you whether revalidation, review or a fresh application fits. Visit Surveying India, see our airport NOC survey services in India, or contact us. We work in Delhi NCR, Mumbai, Pune and Bengaluru. For basics, start with what is AAI NOC and who needs it, and see the colour coded zoning map guide. Verify current rules on the NOCAS FAQ and the Ministry of Civil Aviation website.
Last updated: 4 November 2026. This guide is informational. Your NOC letter and AAI’s current circulars decide your actual dates and conditions.
