a CL601 crew approaching SAN acknowledged TRACON's clearance to 3;800'. After realizing terrain clearance was low and ATC issuing a 'Low Altitude Alert' the crew climbed to 5;000'. The crew believed a busy Controller mistakenly issued the 3;800' clearance.
Synopsis
a CL601 crew approaching SAN acknowledged TRACON's clearance to 3;800'. After realizing terrain clearance was low and ATC issuing a 'Low Altitude Alert' the crew climbed to 5;000'. The crew believed a busy Controller mistakenly issued the 3;800' clearance.
Narrative
SOCAL Approach had cleared us to 5000 FT for vectors to Localizer Runway 27 approach to SAN under visual conditions. At approximately 18 to 20 miles out we were instructed to turn R heading 270 degrees to intercept Localizer Runway 27 and descend to 3800 FT. Both pilots confirmed clearances and readback to Controller exactly as cleared. I should state at this time that the Controller was; in my opinion; under a very heavy load vectoring multiple aircraft to different airports. Upon reaching 3800 FT on the Localizer Runway 27; both pilots observed that we were at the same terrain level as the tops of approaching mountains in both sides ahead of us. We immediately tried to confirm the altitude assigned with the Controller but were unable due to his workload issuing instructions to other aircraft. Within a few seconds the Controller called us with an immediate climb back to 5000 FT. We did so and confirmed that we readback his original clearance to 3800 FT. He then said that clearance was for another aircraft. At 5000 Ft and within 12 miles we were cleared for visual to Runway 27. The following should be noted: The Controller did not confirm our readback of heading or descent to 3800 FT. I am unaware of the limit of how many aircraft a Controller can safely handle but he seemed to be near that limit. Since we were approaching a valley with tops on each side; we never received a terrain warning. Visibility was 10 plus.
Second reporter narrative
ATC Controlling Facility...SOCAL TRACON. We were handed off from LAX Center to SOCAL Approach to begin radar sequencing for a landing at San Diego (SAN) airport. After a series of descents and heading changes; we were approximately 15 miles east of SAN at 5000 FT when the Controller issued the following clearance: 'Our Call Sign; Descend and maintain 3800 FT.' The First Officer acknowledged the clearance...'Roger; Our Call Sign descend and maintain 3800 FT.' Approximately 3 minutes later we heard the following from SOCAL Approach Control...'Our Call Sign I have a low altitude warning on your aircraft; climb immediately to 5000 FT.' I immediately started a climb back to 5000 FT and the First Officer replied...'Roger; Our Call Sign climb to 5000 FT and sir; you gave us 3800 FT.'...SOCAL...'No; your altitude was 5000 FT and 3800 FT was for 8 Foxtrot.' No further comments regarding the altitude disagreement were exchanged and; the next transmission from the Controller was 'Our Call Sign; do you see the airport'...our response...'Roger; we have the airport insight'...Controller...'You are cleared for a visual approach to the airport.' Except for a very late hand off to SAN Tower that we had a prompt SOCAL for; the balance of the approach and landing were routine. I did not receive any instructions from anyone after the incident to phone anyone for explanation regarding the matter. Our crew is reasonably certain that we heard ...Our Call Sign; cleared to 3800 FT. If in fact; our crew got the clearance wrong then...why after our readback; didn't the Controller challenge and or correct any readback mistakes that we made before we made the descent to 3800 FT? If in fact; the clearance was issued to 8 Foxtrot (as claimed by SOCAL) then why didn't we hear something to the effect of SOCAL; this is 8 Foxtrot some other aircraft had read back our clearance (it never happened). Finally; the SOCAL Controller appeared to be extremely busy. I truly believe that if this incident is formally investigate that the voice recording when reviewed; will be fact exonerate our crew of any operational errors regarding this matter.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.