How does this happen?
 

I live on a boat in a marina just 800 meters south of the midpoint of the San Diego airport (KSAN). The KSAN controllers seem to consistently get a plane to land on rwy 27 within 20 seconds of a plane departing on 27 and at times it is less than 15 seconds. As I said initially, I live on a boat very close to the runway and with a clear view of the runway so anytime I am sitting in the cockpit I have a clear view of KSAN operations.

During the last week I have seen four occurrences of a commercial flight approaching runway 27 execute a go around in which they end up flying at 270 magnetic and pass overhead between my boat and the runway while an aircraft departing 27 is still within the vertical extension of rwy27 at less than 300'.

The aircraft executing the go around is within 0.9 miles of the rwy 27 TDZ when they begin the go around and, at the same time, I can plainly see the departing aircraft is only a few hundred feet west of the TDZ.

Yesterday I saw a 737 over the center of runway 27 on the runway heading at less than 1000' while another 737 departing 27 was below it with wheels still fully down and on the identical heading. I was standing 900 meters west of the west end of runway 27, at the same elevation as the runway, looking directly east down the runway and both ac flew directly overhead within seven seconds of each other.

Clear skies, unlimited visibility, light wind in all the situations I am describing.

Several questions:

1 - Why is the Loc 27 missed approach climbing on 275 to 2500' while the RNAV missed approach is climbing left turn to 2500'?

2 - How does the approaching aircraft to rwy 27 get within a mile of the TDZ (not the end of the runway) while a departing aircraft is still east of the TDZ and on the runway?

3 - Does the controller or pilot initiate the go around when the departing aircraft does not clear the runway in time?

I am not trying to be an alarmist - I am just curious as to how this can happen so frequently. During the last year I have seen many dozens of KSAN rwy 27 go arounds where the a/c departing rwy 27 is still on the runway or just lifting off.

Thank you for taking the time to address my curiosity.

I cannot answer 1. 2. I find difficult to believe. If the inbound was at about 300 feet there would not be time for the departing aircraft to start to roll, let alone get far enough down the runway to be safe. 3. Whoever gets in on the R/T first.

Tight separations are essential at very busy airfields and the controllers and pilots are usually very switched-on. In good weather separations maybe reduced significantly when pilots and controllers can see what's happening.