Training / Qualification; Confusion
No Specific Anomaly Occurred All Types
Manuals; Company Policy
I'm writing this report because we have guidance in Chapter 15 of the AOM (Aircraft Operating Manual) regarding windshear that is impossible to follow. In a nutshell; we are given black/white guidance in a very gray area. We are told in para 15.5.1; 'Stay clear of thunderstorm cells; heavy precipitation; and areas of known windshear.' Para 15.5.2 says; 'Do not take off if known windshear exists;' and para 15.5.5 says; 'Do not continue the approach if known windshear exists.' But what exactly is 'known' windshear? It is never defined. I have conversed with several of our company experts over the past few months. In all of my discussions with flight standards; flight operations procedures; and various check airmen no one has been able to define 'known' windshear. One subject matter expert told me that an ATC windshear alert; for example; is 'known' windshear; while another told me it was only an advisory. Which is it? All of the company experts I've spoken with admit 'known' windshear is extremely difficult; if not impossible; to define...yet; we're told we must avoid it. AC 00-54 Pilot Windshear Guide; 2.4.2 states; 'The importance of avoiding severe windshear and microbursts cannot be over-emphasized.' Agreed. It goes on to say that 'Unfortunately; there are no universal quantitative windshear avoidance criteria that provide unambiguous go/no-go decision guidelines.' It provides a Table 1 that gives probability of encountering windshear guidelines; but it also admits the information is a 'subjective evaluation of various observational clues to aid in making real time avoidance decisions.'So; there seems to be a wide and varied interpretation within the pilot group; to include our subject matter experts; over what constitutes 'known' windshear. Even the FAA's evaluation criteria for making a go/no-go decision is subjective. It's for these reasons; the AOM should be changed to either define what company means by 'known' windshear; and give examples for clarity; or rewrite the paragraphs cited above to allow for better risk management decision-making. Providing black/white (objective) guidance in a gray (subjective) environment creates confusion; is ambiguous; and can be detrimental to safety when there is not agreement within the pilot group as to what exactly constitutes 'known' windshear.
Reporter describes ambiguous guidance in company manuals with regard to avoiding known windshear.