AIM ¶ 7-1-22 — Wind Shear PIREPs
AIM 7-1-22 explains how pilots should report wind shear and escape maneuvers to ATC. Study guide for written tests, oral exams, and checkrides.
In Plain English
Wind shear—sudden changes in wind speed or direction—can be deadly at low altitudes near the airport. AIM 7-1-22 urges pilots to promptly report wind shear encounters so others can avoid or prepare for them. This is a recommended practice, not a regulation, but it's a critical safety behavior.
Key reporting guidance:
- Avoid the words "negative" or "positive" wind shear. "Negative wind shear on final" has been misread as meaning no shear was present.
- State the gain or loss of airspeed and the altitudes where it occurred. Example: "Loss of 20 knots at 400 feet."
- If you can't quantify it, describe the effect on the aircraft (e.g., "max thrust required").
- INS-equipped aircraft should report wind and altitude both above and below the shear layer.
Wind Shear Escape: If you execute an escape maneuver, tell ATC as soon as it's safe to do so (e.g., "United 1154, wind shear escape"). Once you initiate the escape, ATC is no longer responsible for separation from traffic, terrain, airspace, or obstacles until you report the maneuver complete and separation is re-established. After completion, advise ATC you're resuming your clearance or request a new one.
AIM Source Text
FAA AIM ¶ 7-1-227-1-22. 7-1-22. Wind Shear PIREPs
Because unexpected changes in wind speed and direction can be hazardous to aircraft operations at low altitudes on approach to and departing from airports, pilots are urged to promptly volunteer reports to controllers of wind shear conditions they encounter. An advance warning of this information will assist other pilots in avoiding or coping with a wind shear on approach or departure. When describing conditions, use of the terms “negative” or “positive” wind shear should be avoided. PIREPs of “ negativewind shear on final,” intended to describe loss of airspeed and lift, have been interpreted to mean that no wind shear was encountered. The recommended method for wind shear reporting is to state the loss or gain of airspeed and the altitudes at which it was encountered. EXAMPLE- Denver Tower, Cessna 1234 encountered wind shear, loss of 20 knots at 400. Tulsa Tower, American 721 encountered wind shear on final, gained 25 knots between 600 and 400 feet followed by loss of 40 knots between 400 feet and surface. Pilots who are not able to report wind shear in these specific terms are encouraged to make reports in terms of the effect upon their aircraft. EXAMPLE- Miami Tower, Gulfstream 403 Charlie encountered an abrupt wind shear at 800 feet on final, max thrust required. Pilots using Inertial Navigation Systems (INSs) should report the wind and altitude both above and below the shear level. Wind Shear Escape Pilots should report to ATC when they are performing a wind shear escape maneuver. This report should be made as soon as practicable, but not until aircraft safety and control is assured, which may not be satisfied until the aircraft is clear of the wind shear or microburst. ATC should provide safety alerts and traffic advisories, as appropriate. EXAMPLE- “Denver Tower, United 1154, wind shear escape." Once the pilot initiates a wind shear escape maneuver, ATC is not responsible for providing approved separation between the aircraft and any other aircraft, airspace, terrain, or obstacle until the pilot reports that the escape procedure is complete and approved separation has been re-established. Pilots should advise ATC that they are resuming the previously assigned clearance or should request an alternate clearance. EXAMPLE- “Denver Tower, United ll54, wind shear escape complete, resuming last assigned heading/(name) DP/clearance." or “Denver Tower, United ll54, wind shear escape complete, request further instructions."
Oral Exam Questions a DPE Might Ask
Q1Why does the AIM recommend against using the terms "negative" or "positive" wind shear in a PIREP?
Per AIM 7-1-22, those terms have caused confusion—"negative wind shear on final," intended to mean a loss of airspeed and lift, has been interpreted to mean no wind shear was encountered. Pilots should instead report the specific gain or loss of airspeed and the altitudes at which it occurred.
Q2How should you report a wind shear encounter to ATC?
Per AIM 7-1-22, the recommended method is to state the loss or gain of airspeed and the altitudes where it was experienced (e.g., "loss of 20 knots at 400 feet"). If you can't quantify it, describe the effect on the aircraft, such as "abrupt wind shear at 800 feet, max thrust required." INS-equipped aircraft should also report wind and altitude above and below the shear level.
Q3What are ATC's separation responsibilities once you initiate a wind shear escape maneuver?
Per AIM 7-1-22, once the pilot initiates a wind shear escape maneuver, ATC is not responsible for providing approved separation between the aircraft and other aircraft, airspace, terrain, or obstacles until the pilot reports the escape complete and approved separation has been re-established. The pilot should then resume the previous clearance or request a new one.
Related Paragraphs in AIM Chapter 7