When an airline’s own pilots call its service “outright embarrassing,” and deride the company’s corporate culture as “toxic,” you can safely say that airline has a problem.

American Airlines, the world’s largest airline, has a problem.

In a letter sent last week to American’s chairman and CEO, Doug Parker, the Allied Pilots Association, which represents American’s pilots, pulled no punches in excoriating the company’s management policies and practices.

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Among the APA’s grievances and demands:

The merger of American Airlines and US Airways happened in large measure because of labor’s support. We believed in your promise of real cultural change. Unfortunately, your management team is now failing to deliver on that promise.

We’re seeing (in your words) the “old school playbook” with “rules-based management” and “cut-throat and heartless” operating methods.

Candidly, the new American Airlines product is outright embarrassing and we’re tired of apologizing to our passengers. We hear from many valuable corporate clients and premier status passengers that the product is not what they’ve come to expect from American Airlines.

We must see meaningful and immediate culture change. Without it, American Airlines will never be restored to a position of industry leadership and our legacy will be one of opportunity lost.

The clock is ticking and the time for inspiring words has passed.

The harsh words follow years of strained relations between American and its unions, and their eventual support for what amounted to a hostile takeover of American by Parker and US Airways.

Parker’s relationship with labor during his US Airways tenure fell well short of lovey-dovey, so it’s unclear whether he has the will or the skill to defuse what has become an increasingly adversarial relationship with American’s unions. In the meantime, the airline’s already middling customer-service levels are further threatened by a disgruntled workforce.

The clock is ticking.

Reader Reality Check

Have you noticed heightened levels of edginess and frustration in your recent dealings with American employees?

After 20 years working in the travel industry, and almost that long writing about it, Tim Winship knows a thing or two about travel. Follow him on Twitter @twinship.

This article first appeared on SmarterTravel.com, where Tim Winship is Editor-at-Large.