The perp flees the pickup on a highway. He finally takes an exit which splits into two lanes (a right turn and a left turn at the end of the ramp. As he gets into the left turn lane, there are 4 cars ahead of him and 7 vehicles and a motorcycle in the right lane. The next view of the perp is from the back seat of his car. BUT suddenly, there are now only 2 cars ahead of him and NO cars in the right lane.
The perp suddenly sees a police car quickly approaching him from ahead. He looks in his rear view mirror and sees another police car rapidly closing in on him from the rear. He turns the car around and goes through an open gate and onto the ramp which will take him to the river. He then stops the car, gets out, fiddles with the chain, and finally locks the chain (thereby locking the gates shut). He then gets back into his car, drives it down the ramp and into the river. He does all of this before the police finally arrive (after a considerable delay) at the spot where he was when he initially spotted the police hotly closing in on him. Makes one think that perhaps the police might have stopped and had a donut or two before continuing the chase.
During the final chase scene along the LA River, there are several shots from the car's driver's point of view of the helicopter, interspersed with shots from well above the helicopter looking down. From the ground, the helicopter appears to be hundreds and hundreds of feet above him. From the aerial view, the helicopter is perhaps one hundred feet above the ground.
As they are following Mona's white convertible with the helicopter, there are a number of shots taken from below the pilot looking upwards through the bubble. In an early scene, while the helicopter is supposed to be in flight, the rotor blades are seen to be barely turning, as if the helicopter had just been started.
When the station wagon is shown driving through the water in the LA River, you can see the spray from the camera vehicle driving in front of it. At one point you can even see a localized "rainbow" in the shot from the spray.
Many times during the helicopter chase scene, when the pilot speaks into the microphone, the words you hear are very obviously not the words that he is saying.
Sgt. Castle knows he is scheduled to fly at 7 the next morning, yet he drinks a glass of wine. FAA regulations prohibit pilots from consuming alcohol within 24 hours of piloting an aircraft.