With the markets in a tailspin over events in China and Greece, I thought it would be good to get some commentary on the global industrial economy. The earnings call at aluminum and alumina producer Alcoa (NYSE:AA) is a great place to start. Its management always delivers solid guidance on its end markets, and what it says has direct relevance to industrial bellwethers General Electric Company (NYSE:GE) and United Technologies Corporation. Let's take a look at Alcoa's recent results and take a deeper dive into what's going on with the global economy.

Alcoa's end-market outlook
The following table summarizes how Alcoa's management sees growth in various end markets in 2015. The outlook is updated every month and provides a useful snapshot of the global economy. As a provider of basic materials to the industrial sector, Alcoa's sales provide insight into which industries are growing and which aren't. I've noted the changes in italics below.

Segment

Q4 2014 Growth

Q1 2015 Growth

Q2 2015 Growth

Aerospace

9% to 10%

9% to 10%

8% to 9%

Automotive

2% to 4%

2% to 4%

2% to 4%

Heavy-Duty Truck & Trailer

(1%) to 3%

(2%) to (4%)

(4%) to (6%)

Packaging

2% to 3%

2% to 3%

2% to 3%

Building & Construction

5% to 7%

5% to 7%

5% to 7%

Industrial Gas Turbines

1% to 3%

1% to 3%

1% to 3%

Source: Alcoa presentations.

There haven't been many changes, but a closer look at the geographic breakdown, along with management commentary, reveals some interesting underlying trends.

Aerospace and Automotive
The reduction in the 2015 growth forecast is superficially concerning, but on the earnings call, CEO Klaus Kleinfeld said it's "entirely due to the shift that we are seeing on the slow platform ramp-up -- mainly, the A350 and the CSeries." The CSeries is Bombardier's troubled single-aisle jet, intended to compete with planes from Boeing and Airbus, manufacturer of the A350.

While Alcoa's outlook suggests that suppliers to the A350 -- such as Precision Castparts and United Technologies' UTC Aerospace Systems -- may see the negative effects of the slower ramp-up, it doesn't mean there's anything fundamentally wrong with the aerospace market. On the contrary, Kleinfeld argued that the work would move in to next year, and he promptly doubled Alcoa's forecast for end-market aerospace growth in 2016/2017.

Turning to automotive, conditions appear to be stable across the board, with Kleinfeld emphasizing the strength in North American light-truck sales compared with a relatively weaker passenger-car market.

Automotive Market

Q42014 Growth

Q1 2015 Growth

Q2 2015 Growth

North America

1% to 4%

1% to 4%

1% to 4%

EU

(1%) to 3%

(1%) to 3%

(1%) to 3%

China

5% to 8%

5% to 8%

5% to 8%

Source: Alcoa presentations.

Heavy-Duty Truck & Trailer, and Building & Construction
The headline forecasts in the first table indicate a deterioration of prospects for this segment, but it's a mixed story on a regional basis. Conditions are getting stronger in North America and Europe, while truck sales in China are suffering from what Kleinfeld described as a "strong pull ahead that they had due to the Stage IV regulations." In other words, there was strong buying ahead of the implementation of new emissions standards in January.

Heavy Duty Truck & Trailer Market

Q42014 Growth

Q1 2015 Growth

Q2 2015 Growth

North America

3% to 7%

6% to 8%

9% to 11%

EU

(5%) to (10%)

(5%) to (7%)

(2%) to 0%

China

(2%) to 2%

(9%) to (11%)

(14%) to (16%)

Source: Alcoa presentations.

Of course, the issue could be clouding a general slowdown in China's industrial sector, and the only change in the regional outlook for building and construction was a slight reduction in the outlook for China.

Building & Construction Market

Q42014 Growth

Q1 2015 Growth

Q2 2015 Growth

North America

4% to 5%

4% to 5%

4% to 5%

EU

(2%) to (3%)

(2%) to (3%)

(2%) to (3%)

China

7% to 9%

7% to 9%

6% to 8%

Source: Alcoa presentations.

If China's construction sector is about to slow down, then it will obviously be a concern for United Technologies investors, as its elevator unit, Otis, has strong exposure to China.

Industrial Gas Turbines
The outlook for industrial gas turbines remains stable, but Kleinfeld's commentary will interest General Electric investors. GE is trying to establish orders for its new, more energy-efficient HA gas turbines. That made Kleinfeld's discussion on the earnings call notable, as he spoke of "new high-efficiency turbines with advanced technology that customers find attractive" and, secondly, "the strong U.S. 60 Hz gas-fired market," which is "up 19.5% year to date, and that also drives a strong demand for spares and component upgrades for existing turbines."

Although he went on to point out that weakness in European markets countered the strength in the U.S., this is nevertheless a good sign for GE's core marketplace.

The key takeaways
While Alcoa's share price has taken a hit due to a global aluminum surplus, its management's commentary on its end markets was relatively upbeat. There are some signs of weakening in China, but the general outlook for the aerospace and automotive sectors remains positive.

Meanwhile, General Electric followers will like the positive comments made on spending in North America on gas turbines. In addition, the heavy-duty-truck marketplace is seeing notable outperformance from North America, and building and construction remains strong in North America.

Lee Samaha has no position in any stocks mentioned. The Motley Fool recommends Precision Castparts. The Motley Fool owns shares of General Electric Company. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.