New Aeroautical Assessment Form (AAF) for Obstacle Notice and Assessment

Transport Canada’s Eduard Alf sent the following email to some tower industry stakeholders this month and generously agreed to permit STAC to re-post the contents of his message, which is included below.

In a follow-up email, Eduard also asked STAC to stress that this material is for information only, adding: “Transport Canada isn’t looking for anyone to do something right now, unless they’ve [got] a new project.”

The message and related attachments can each be found below.

Aeronautical assessment form for obstacle notice and assessment
Formulaire d’évaluation Aéronautique pour l’avis et l’évaluation d’obstacles

Original message as follows:
From: Alf, Eduard <>
Sent: June 18 2019 5:13 AM
Subject: AAF 26-0427 (1812-09)


Sending to stakeholder distribution….

For your information, attached is the newly revised AAF (Aeroautical Assessment Form) for obstacle notice and assessment.

26-0427E (2018-09)
26-0427F (2018-09)

You can get these forms from the Forms Catalogue, on the Transport Canada website. The following links are for the Forms Catalgue search function. You’ll need to enter the name or number of the form. Typing in the number 26-0427 is best.

You’ll note that we’ve reduced the size of the form; from 4 pages to 2 pages, for purpose of simplification. Instead of by way of checkoff boxes, the proponent identifies the marking/lighting/monitoring to be installed in the Description of Project box or as separately attached.

The criteria for submittal follows FAA practice for notification, except we’ve used a 2% slope instead of 1%. And 4% for heliports and water aerodromes. For water aerodromes the start of the slope is at the published GPS point. The slopes go out to 90m height and then level off at 90m above the runway threshold end elevation and then out to 6km [3.2 nautical miles]. The FAA slope goes out to 200ft [60m].

The intent of the criteria is the same as for FAA. That is, to capture projects that’d be of interest to Transport Canada. As in the case of the FAA, the criteria isn’t a standard for marking/lighting. It’s a criteria that leads to assessment.

The form is intended to be used electronically and thus doesn’t require signatures. The inspector simply adds their name and the date. Same for the proponent. This obviates the need for physically signing the form and thereafter scanning in order to be sent by email.

The box for Transport Canada Assessment will identify the marking/lighting/monitoring requirement. This is with respect to “Protection”. That is, Night Protection or Day Protection. Exactly what lighting/marking/monitoring would be installed is up to the proponent in following Standard 621.

Transport Canada may also make a comment in their Assessment box. This may happen in such as broadcast antennas near an airport where there may be an issue of interference with electronic navaids. It may specify a period of testing to verify absence of interference.