Image source: Alcoa.

As a pioneer in the aluminum industry, Alcoa's (NYSE: AA) earnings release sets the tone for the earnings season, especially for industrial companies. So whether you're an investor in heavy-equipment manufacturers such as Deere & Company (NYSE: DE) and Caterpillar (NYSE: CAT), or truck and engine companies such as Cummins Inc. (NYSE: CMI) and Paccar (NASDAQ: PCAR), Alcoa's outlook about key end markets can give you a great idea about what to expect when your company reports its quarterly earnings.

For instance, consider some of the things that Alcoa said during its first-quarter earnings release last week:

1. N.A. Heavy-duty truck build rates continue to decline.

2. Brazil's current economic environment continues to negatively impact business results.

3. Oil & gas, European industrial gas turbine, North America commercial transportation markets increasingly softer.

These comments from Alcoa hold valuable information that investors in heavyweights such as Caterpillar, Deere, Paccar, and Cummins can use to prepare themselves to avoid nasty shocks when these companies release their numbers and guidance over the next few weeks. To know how, click on the following slideshow now.