Date: 201812
Local time of day: 1201-1800
Location: MSLP.Airport, FO
Flight conditions: VMC
Aircraft: B737 Next Generation Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Climb
ATC / advisory: Tower MSLP
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation - Altitude Crossing Restriction Not Met; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Human Factors

Narrative: During preflight; the incorrect SID was entered and was not recognized until after takeoff. Our clearance was Relta3.B. Relta3 was entered. In SAL; there are 4 Reltas - (Relta3.; Relta3.A; B; and C - 737 is not allowed to do Relta3C). First Officer received the clearance; and read it back; I monitored. We briefed in several stages- prior to the clearance; I briefed terrain and what he could expect for the SID because he was unfamiliar with SAL. He got the clearance; I heard him read back 'Relta3.B' and when we briefed just prior to the checklist; it was verbalized again. In the FMC; I verified on Departure page 2 that it said Relta3; BUT with no B. This gave me a momentary pause that if I had followed up on adequately or more thoroughly; I wouldn't need to file this [report]. The FMC departure page 2 indicated Relta3.Relta in 1L; and Relta in 1R; not Relta3B in 1L and Relta in 1R. When I looked on the legs page; the first couple points seemed to be what I was expecting so I didn't investigate further. After takeoff; the nav display was showing a tear drop course reversal to the right; when Relta3B indicates turning left to intercept CAT R351. Putting this together quickly while the First Officer was hand flying; I realized the incorrect SID had been entered into the FMC. I told the First Officer (flying pilot) to turn to the left; and manually set him up for the radial intercept. This happened quickly; and I missed the altitude requirement to meet prior to turning clearly indicated on the SID page in the Initial Climb section. In my hurry; I only saw 'turn left heading 315 to intercept CAT 351 to Relta' indicated in the routing section. Not long after the turn; Departure queried; and subsequently made it clear that we had turned too early; but he was saying other things with such a thick accent it was difficult to understand exactly what else we had done wrong. I am still uncertain if we encroached on airspace; or if we caused a traffic conflict; or just irritated the Controller by messing up. Terrain clearance was never an issue; and we didn't see any traffic on TCAS. Upon review; we definitely turned too early; and at night or IMC this could have been a grievous error. Luckily; it was VMC with high ceilings and good visibility.


Second narrative: We were given our clearance. I did say 3B; but did not say Relta on the readback. There was a slight language barrier; but the read back he replied was correct. I briefed the Relta 3 which was a right hand turn at 2;500 feet. We departed and at 2;500 feet; I began my right hand turn. At that time; the Captain said we should be coming left to a 315 heading for the Relta3B departure. I turned left to the 315 heading and realized I had [loaded] the Relta3. As the turn was established; Tower informed us we needed to be at/above 8;000 feet by 15 DME per the Relta3B departure. A little language barrier; but that was his verbal intent. I pulled up the Relta3B. We were able to comply with the altitude with no problem. We departed uneventfully; but were informed by the Tower to fly the proper departure. Once we were on autopilot and at cruising altitude; we discussed the occurrence to prevent it from happening again.


Synopsis: B737NG flight crew reported a track deviation occurred departing MSLP when the crew loaded the wrong departure.