Complex sentence: At the deployment of the slats, one of these fell off while the plane was travelling at a speed of descent, In reality the pilots were raising the power to travel over 1100 KPH, too high for this type of airplane.
Split into simpler sentences: At the deployment of the slats, one of these fell off while the plane was travelling at a speed of descent. Actually, the pilots were raising power to travel over 1100 KPH, too much for this type of airplane.