About the time Air Force One leaves the ground this morning, carrying President Carter on his trip to four countries in South America and Africa, officials at the Labor Department will begin briefing reporters on the February Consumer Price Index.

In the White House he is leaving behind - and among some leading officials of his party - there is a fear that the coincidence of the two events will dramatize what they see as the persistent, debilitating fault of Carter's presidency: the inability to focus on, and anticipate, truly critical problems.

Inflation is one such problem and, unless all the portents prove wrong, this morning's consumer price index is going to confirm everyone's worst fears about the surge in the price spiral.

No one minimizes the political damage such news will likely cause. Inflation is the country's main concern and its resurgence can cause Carter's support, which appeared to have bottomed out at the 50-percent confidence level, to drop to new lows in the seven months before the mid-term election.

So, as one prominent Democrat put it, "What in the hell is he doing off in Caracas when inflation is going through the roof?"

The answer to that question takes administration offivials back through a series of "horror stories" all illustrating Carter's failures in strategic planning.

The trip beginning today is the leftover portion of an ambitious 1977 journey concocted by national security advisor Zbigniew Brzezinski as a way of dramatizing what he considered the basic themes of Carter's foreign policy. Domestic political advisors have never considered the trip a necessity. But they were never able to dislodge it from his schedule.

The trip was postponed once, last fall, to permit Carter to stay in Washington for what his legislative aides thought would be the showdown on his energy legislation. But they miscalculated, and Carter suffered the embarrassment of sitting around the White House while Congress ignored the energy package.

Another schedule snafu has just left Carter squeezed for time to shape the urban-policy decisions announced yesterday. One assistant called the urban operation "the worst nightmare we've gone through since the energy policy mess a year ago."

Wearied by days of anxious lobbying on the Panama treaty - another Brzezinski project, domestic advisors note - and tough, unsuccessful negotiations with Israel Prime Minister Menachem Begin, Carter had to get up at 5 a.m. Friday to finish reading the final staff recommendations on the urban-policy project begun a year before.

He rejected half of them out of hand. But with a public commitment to unveil his program before the start of today's trip, the staff convinced Carter there was no time left to make basic changes in the package.

As a result, he committed himself yesterday to a basic domestic program that falls far short of his own expectations.

Coming atop the impasse on energy legislation, the Middle East stalemate and the warning signs of worsening U.S.-Soviet relations, Carter does not need another huge headache.

But that is what inflation is likely to be. As far back as December 1976, Patrick Caddell, Carter's pollster, wrote that if Carter were to be reelected, "we must allevate fears of inflation. Simply telling the public that inflation is not a problem is not going to do the trick."

As Caddell noted, Carter was the only Democrat in 1976 to put great emphasis on the inflation issue. Many - including Mrs. Rosalynn Carter - believe that it was that factor, as much as any, that explained his success.

But the surge in inflation poses equally grave risks. A Harris Poll earlier this month found 82 percent of the voters naming "rising prices" as the most serious problem facing their families.

With food prices - an expecially sensitive problem - leading the surge, there is no doubt among Carter's political advisers that inflation will cause him and other Democrats what one adviser called "severe political problems."

With that judgment, the question arises why Carter has not moved to head off the criticism. There are two answers - reflecting what appears to be a serious split within the White House staff.

Political advisers blame Carter's economic team for not providing early warning of the inflationary upsurge. As the year began, Carter's economists were predicting that inflation would remain at roughly a 6 percent level and were talking hopefully of a mild form of government persuasion that might reduce that figure slightly and thus ease the "inflationary psychology." That prediction appears now to be seriously over-optimistic.

"If I were a decision-maker," said one political adviser to the President, "I would want to know why I wasn't warned."

But the economists reply that Carter's political advisers have been dragging their feet, even since they told them that the storm warnings were flying on inflation.

Three weeks ago, on March 7, Barry Bosworth, the director of the Council on Wage and Price Stability, warned in a memo that the next few months of news on the inflation front, starting with today's CPI, would be bad. He urged the President to "anticipate, [TEXT OMITTED FROM SOURCE] And he gave him suggestions for a stiffened anti-inflation program which Bosworth said should be a subject of a presidential address.

Since then, a number of meetings have been held but nothing has come of them, as far as is publicly known. Again, the split shows in the explanations that are given. The political advisers say the recommendations from Bosworth and others were ineffective and "gimmicky." The economic advisers say the political people were unwilling to offend any important group - farmers, government employes, environmentalists - in order to show there was some muscle to the ineffectual Administration anti-inflation program.

But there is another explanation one hears around the White House, which is more ominous in its implications. It is that even now, 14 months into his presidency, Jimmy Carter has not found a way of organizing his job that allows him to cope with both immediate crises and long-term problems, or to sort out what is trivial from what is essential in his work.

In this perspective, even an administration "victory" like the ratification of the first Panama Treaty, is seen by some advisers as reflecting the shakiness of the Carter White House.

"Panama was a disaster for us," said one adviser. "For three weeks, Jimmy Carter could hardly think about or spend time on anything else. It just consumed him. And what the hell did we win when we won it?"