Narrative:

I was cleared and was executing ILS runway 24L approach at cleveland. ATIS information: wind 160 degrees/6 KTS, visibility 6 mi (light rain), ceiling 1300 ft overcast, temperature 6 degrees, dewpoint 6 degrees, altimeter 29.98. At approximately 3.5 DME, just below 1000 ft AGL, and still IMC, tower said, 'company flight number, cleared to sidestep to runway 24R.' there was no previous notification of a sidestep by either approach or tower. I responded, 'company flight number, does not have the airfield in sight.' tower then told us (I cannot recall the exact verbiage) that if we could not sidestep within a half mi, he would have to send us around since there was an aircraft still 'in position' on runway 24L. As tower was saying this, we broke out of the WX (approximately 750-800 ft AGL), and I picked up the airfield. I immediately relayed that I had the airfield in sight and was executing the sidestep maneuver. We stabilized on final right at the 500 ft AGL minimum, and continued the visual approach to an uneventful landing on runway 24R. I think the decisions I made were logical and safe, however, a number of questions came afterwards that made me wonder if I had done something that was not legal, or if the tower operator's actions were not legal. First, I did not think the tower could direct an aircraft on an instrument approach (especially in IMC) to perform a visual approach (sidestep) to another runway. Second, there is no sidestep procedure published for a sidestep from runway 24L to runway 24R (there is a procedure from runway 24R to runway 24L, we discovered later), so how do I know the runways are within the 1200 ft required for a legal sidestep? Finally, from 750-800 ft AGL, when I got the airfield in sight, I was barely able to arrive in a stabilized position for a visual approach on runway 24R by the time I reached 500 ft AGL. The fom (recent change) says we are permitted to maneuver to a sidestep runway below 1000 ft/3 mi as long as we're stabilized on final by 500 ft AGL. Given a 3 degrees visual GS and a maximum of 1200 ft horizontal separation to sidestep runways, shouldn't we have a minimum sidestep altitude so the crew doesn't have to guess? These questions raced through my mind in the few seconds I had to make the decision to accept the controller's directions, and that is the reason for this as soon as possible report.

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Original NASA ASRS Text

Title: B737 CREW ON ILS APCH TO CLE RWY 24L JUST BELOW 1000 FT IMC ARE UNEXPECTEDLY INSTRUCTED TO SIDESTEP TO RWY 24R.

Narrative: I WAS CLRED AND WAS EXECUTING ILS RWY 24L APCH AT CLEVELAND. ATIS INFO: WIND 160 DEGS/6 KTS, VISIBILITY 6 MI (LIGHT RAIN), CEILING 1300 FT OVCST, TEMP 6 DEGS, DEWPOINT 6 DEGS, ALTIMETER 29.98. AT APPROX 3.5 DME, JUST BELOW 1000 FT AGL, AND STILL IMC, TWR SAID, 'COMPANY FLT NUMBER, CLRED TO SIDESTEP TO RWY 24R.' THERE WAS NO PREVIOUS NOTIFICATION OF A SIDESTEP BY EITHER APCH OR TWR. I RESPONDED, 'COMPANY FLT NUMBER, DOES NOT HAVE THE AIRFIELD IN SIGHT.' TWR THEN TOLD US (I CANNOT RECALL THE EXACT VERBIAGE) THAT IF WE COULD NOT SIDESTEP WITHIN A HALF MI, HE WOULD HAVE TO SEND US AROUND SINCE THERE WAS AN ACFT STILL 'IN POS' ON RWY 24L. AS TWR WAS SAYING THIS, WE BROKE OUT OF THE WX (APPROX 750-800 FT AGL), AND I PICKED UP THE AIRFIELD. I IMMEDIATELY RELAYED THAT I HAD THE AIRFIELD IN SIGHT AND WAS EXECUTING THE SIDESTEP MANEUVER. WE STABILIZED ON FINAL RIGHT AT THE 500 FT AGL MINIMUM, AND CONTINUED THE VISUAL APCH TO AN UNEVENTFUL LNDG ON RWY 24R. I THINK THE DECISIONS I MADE WERE LOGICAL AND SAFE, HOWEVER, A NUMBER OF QUESTIONS CAME AFTERWARDS THAT MADE ME WONDER IF I HAD DONE SOMETHING THAT WAS NOT LEGAL, OR IF THE TWR OPERATOR'S ACTIONS WERE NOT LEGAL. FIRST, I DID NOT THINK THE TWR COULD DIRECT AN ACFT ON AN INST APCH (ESPECIALLY IN IMC) TO PERFORM A VISUAL APCH (SIDESTEP) TO ANOTHER RWY. SECOND, THERE IS NO SIDESTEP PROC PUBLISHED FOR A SIDESTEP FROM RWY 24L TO RWY 24R (THERE IS A PROC FROM RWY 24R TO RWY 24L, WE DISCOVERED LATER), SO HOW DO I KNOW THE RWYS ARE WITHIN THE 1200 FT REQUIRED FOR A LEGAL SIDESTEP? FINALLY, FROM 750-800 FT AGL, WHEN I GOT THE AIRFIELD IN SIGHT, I WAS BARELY ABLE TO ARRIVE IN A STABILIZED POS FOR A VISUAL APCH ON RWY 24R BY THE TIME I REACHED 500 FT AGL. THE FOM (RECENT CHANGE) SAYS WE ARE PERMITTED TO MANEUVER TO A SIDESTEP RWY BELOW 1000 FT/3 MI AS LONG AS WE'RE STABILIZED ON FINAL BY 500 FT AGL. GIVEN A 3 DEGS VISUAL GS AND A MAX OF 1200 FT HORIZ SEPARATION TO SIDESTEP RWYS, SHOULDN'T WE HAVE A MINIMUM SIDESTEP ALT SO THE CREW DOESN'T HAVE TO GUESS? THESE QUESTIONS RACED THROUGH MY MIND IN THE FEW SECONDS I HAD TO MAKE THE DECISION TO ACCEPT THE CTLR'S DIRECTIONS, AND THAT IS THE REASON FOR THIS ASAP RPT.

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.