Narrative:

Houston area was covered in thunderstorms. Arriving from northeast, we were held and vectored south of hobby until field began to clear somewhat. We were cleared direct to hobby (on approximately 220 degree radial, inbound). Proceeding inbound, approach control cleared us to 4000 ft, cleared for ILS runway 4 at hobby. We were switched to tower at 25 DME. (I thought that this was early, that's why I specifically noted DME.) I checked in with tower. Captain (PF) was on localizer 4. I stayed on hou VORTAC guidance, as was my practice until closer to field (when PNF and captain shooting an ILS). We were concerned with cells on final and focused on radar. Captain stated that he was going a bit left to avoid cell (left of course). When we passed DME for 4000 ft limit we began descent to 2000 ft. Unfortunately, I was focused on checklist, altitude, storms, and didn't back up my captain sufficiently. We had drifted way left of localizer. Wind from ese also made off course worse. Tower called us and told us to climb to 3000 ft and contact approach. We switched and climbed. On check-in we were told of 2049 ft MSL towers southwest of hobby, which we had come close to. We were vectored around for safe approach. Mistakes/lessons learned: 'classics' -- don't lose 'big picture' by overly focusing on one thing! Localizer altitudes only good if on course! Xchk and question other pilot's instruments (HSI) display. Personal: question early switch to tower. No need to stay on VORTAC so long. If ILS has DME and there is outer compass locator (like at hou runway 4), there is bearing and distance while on localizer. Supplemental information from acn 367116: the controller told us that our initial approach clearance was to maintain 4000 ft and contact the final approach controller, however, both the copilot and I distinctly remember the clearance for the ILS approach and the switch to tower because we both mentioned how far out it was to be switched to the tower. Because of the confusion over the clearance and the frequency change, approach could not contact us to notify us that we were drifting dangerously close to the antennas, and they did not know that we had gone to tower. Tower had no radar(?) so they had no clue that we were so far off course. The winds at 3000-4000 ft were out of the southeast at over 40 KTS. Since we were in an older airplane, with no wind readout, we had no idea at that time that our correction back to the ILS course was inadequate. When on the ground, following the second approach, we were told to call TRACON. We were able to reconstruct what had happened.

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Original NASA ASRS Text

Title: B737-200 ON VECTOR HDG TO INTERCEPT THE HOU RWY 4 LOC AND CLRED FOR APCH AND TOLD TO CONTACT THE FINAL CTLR. THE FLC MISINTERPED THE CLRNC AND CHANGED TO HOU TWR FREQ IN ERROR AND THEN DEVIATED FOR WX ON THE FINAL APCH WITHOUT A CLRNC. DURING THE DEV THE ACFT CAME CLOSE TO AN ANTENNA AND WAS INSTRUCTED TO CLB AND CONTACT DEP CTL FOR ANOTHER VECTOR TO THE ILS.

Narrative: HOUSTON AREA WAS COVERED IN TSTMS. ARRIVING FROM NE, WE WERE HELD AND VECTORED S OF HOBBY UNTIL FIELD BEGAN TO CLR SOMEWHAT. WE WERE CLRED DIRECT TO HOBBY (ON APPROX 220 DEG RADIAL, INBOUND). PROCEEDING INBOUND, APCH CTL CLRED US TO 4000 FT, CLRED FOR ILS RWY 4 AT HOBBY. WE WERE SWITCHED TO TWR AT 25 DME. (I THOUGHT THAT THIS WAS EARLY, THAT'S WHY I SPECIFICALLY NOTED DME.) I CHKED IN WITH TWR. CAPT (PF) WAS ON LOC 4. I STAYED ON HOU VORTAC GUIDANCE, AS WAS MY PRACTICE UNTIL CLOSER TO FIELD (WHEN PNF AND CAPT SHOOTING AN ILS). WE WERE CONCERNED WITH CELLS ON FINAL AND FOCUSED ON RADAR. CAPT STATED THAT HE WAS GOING A BIT L TO AVOID CELL (L OF COURSE). WHEN WE PASSED DME FOR 4000 FT LIMIT WE BEGAN DSCNT TO 2000 FT. UNFORTUNATELY, I WAS FOCUSED ON CHKLIST, ALT, STORMS, AND DIDN'T BACK UP MY CAPT SUFFICIENTLY. WE HAD DRIFTED WAY L OF LOC. WIND FROM ESE ALSO MADE OFF COURSE WORSE. TWR CALLED US AND TOLD US TO CLB TO 3000 FT AND CONTACT APCH. WE SWITCHED AND CLBED. ON CHK-IN WE WERE TOLD OF 2049 FT MSL TWRS SW OF HOBBY, WHICH WE HAD COME CLOSE TO. WE WERE VECTORED AROUND FOR SAFE APCH. MISTAKES/LESSONS LEARNED: 'CLASSICS' -- DON'T LOSE 'BIG PICTURE' BY OVERLY FOCUSING ON ONE THING! LOC ALTS ONLY GOOD IF ON COURSE! XCHK AND QUESTION OTHER PLT'S INSTS (HSI) DISPLAY. PERSONAL: QUESTION EARLY SWITCH TO TWR. NO NEED TO STAY ON VORTAC SO LONG. IF ILS HAS DME AND THERE IS OUTER COMPASS LOCATOR (LIKE AT HOU RWY 4), THERE IS BEARING AND DISTANCE WHILE ON LOC. SUPPLEMENTAL INFO FROM ACN 367116: THE CTLR TOLD US THAT OUR INITIAL APCH CLRNC WAS TO MAINTAIN 4000 FT AND CONTACT THE FINAL APCH CTLR, HOWEVER, BOTH THE COPLT AND I DISTINCTLY REMEMBER THE CLRNC FOR THE ILS APCH AND THE SWITCH TO TWR BECAUSE WE BOTH MENTIONED HOW FAR OUT IT WAS TO BE SWITCHED TO THE TWR. BECAUSE OF THE CONFUSION OVER THE CLRNC AND THE FREQ CHANGE, APCH COULD NOT CONTACT US TO NOTIFY US THAT WE WERE DRIFTING DANGEROUSLY CLOSE TO THE ANTENNAS, AND THEY DID NOT KNOW THAT WE HAD GONE TO TWR. TWR HAD NO RADAR(?) SO THEY HAD NO CLUE THAT WE WERE SO FAR OFF COURSE. THE WINDS AT 3000-4000 FT WERE OUT OF THE SE AT OVER 40 KTS. SINCE WE WERE IN AN OLDER AIRPLANE, WITH NO WIND READOUT, WE HAD NO IDEA AT THAT TIME THAT OUR CORRECTION BACK TO THE ILS COURSE WAS INADEQUATE. WHEN ON THE GND, FOLLOWING THE SECOND APCH, WE WERE TOLD TO CALL TRACON. WE WERE ABLE TO RECONSTRUCT WHAT HAD HAPPENED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.