African heads of state arrived in this oil boomtown on the west coast of Africa today for the annual summit meeting of the Organization of African Unity, which appears more divided than ever before in its checkered 14 year existence.

The ideological split between radicals and moderates was reflected in the failure of a six-day foreign ministers' session to come to terms with any of the basic problems troubling the 49nation organization.

By nightfall, 14 heads of state had arrived. More than 20 were expected for the fourday session starting Saturday - an improvement over last year's meeting in Mauritius, which attracted only nine top leaders.

But the improved attendance could not mask the fact that except for Mengistu Haile Mariam of Marxist Ethiolpia, no major figure from radical Africa was expected. Among the absentees was to be Ugandan President Idi Amin, whose plan to miss the conference was reported today by Uganda radio.

After several years of lowprofile behavior, the moderates were ready to raise their voices against Cuba's military presence in Africa and against wholesale questioning of national frontiers inherited from European colonizers.

But observers doubted hthe moderates' muscleflexing would have much effect, since in the past the OAU's most ringing decisions have often been ignored.

Today's radicals and moderates find themselves in major agreement only in their demands for an immediate end to white rule in Rhodesia, Namibia (Southwest Africa) and South Africa.

In recent years the quarrels have degenerated into violence among OAU members.

In the stragegic Horn of Africa, Ethiopia is pitted against both Sudan and Somalia, which claims part of its territory. Somalia is at loggerheads with Kenya, which has charged Somalia with invading northeastern Kenya.

Inside disintegrating Ethiopia, guerrillas control much of Eritrea Province, which stands on the stragegic Red Sea coast opposite Yemen and Saudia Arabia.

To the west, Chad has charged Libya with occupying 45,000 square miles of its territory and aiding antigovernment insurgents.

In central Africa, Zaire has not forgotten the spring incursion launched from neighboring Angola. Indeed the offensive of the moderates can be traced to the aid Zaire received from Morocco, which sent 1,500 troops, and France, which provided the aircraft to fly them in.

The most intractable problem of all remains the escalating fighting over the former Spanish Sahara. It pits Algerianbacked Polisario guerrilas against Morocco and Mauritania, which annexed the phosphaterich territory in the first overt violation of the African borders, often ethnically aritificial, laid down by European colonialists at the 1885 Congress of Berlin.

In a move symptomatic of their partial paralysis, the foreign ministers decided to set up another committee to study the key issue of outside interference in member states' internal affairs.

Senegal asked all member states and foreign powers to keep hands off internal African problems, sought to have OAU members ban use of their territory for aggression against other African countries, and recommended peacefuly settlement of all problems through negotiation and mediation.

Algeria blocked approval of this approach, which was aimed especially at Cuba and the Soviet Union. Agleria instead insisted on the rights of all peoples to selfdeterminations. This was its way of pressing its case for lthe Polisario, but if selfdetermination should become the rule it would change much of the map of Africa.

News services reported these other African developments:

President Julius Nyerere of Tanzania suggested that temporary arrangements by made to keep the East African Community of Tanzania, Kenya and Uganda alive while its future is studied. Reuter quoted Uganda radio as saying Amin could not accept Nyerere's proposal because he thinks the existing treaty must be respected.

Norwegian missionary sources in Addis Ababa said calm had returned to the village of Beica in western Ethiopia after an attack by unidentified troops, Agence FrancePresse reported. Militiamen were said to have driven the invaders out of the town.