Narrative:

VFR, night arrival into lga. A lda-alpha approach to runway 22 was briefed with the ILS to runway 22 as the backup approach. Lga approach control vectored us east of the field at 3000 ft MSL. Abeam the airport, approach asked if we had the field in sight. We responded positively and were given clearance to descend to 2500 ft and cleared the visual approach to runway 22. The controller added a nonstandard restr to not descend below 2500 ft until on final or when given clearance to descend below 2500 ft by the tower. The autoplt was disengaged and descent began for 2500 ft. Approach control issued a TA for another aircraft on final runway 22. The traffic was acquired and a frequency change was made to lga tower. Tower confirmed a clearance for the visual approach to runway 22. When adequate separation with the traffic on final was ensured, I began a left base at approximately 3.5 NM from the approach end of runway 22 and a call was made to the tower per previous request. The aircraft was configured with 2 and then 5 degree flaps. The captain commented we looked high and close to the runway and recommended extending the landing gear and expediting the descent. I angled the aircraft slightly away from the runway and said I understood our clearance to be 2500 ft, until cleared lower. The captain said since we were cleared for the visual approach by the tower, there was no longer an altitude restr. That made sense to me, despite my awareness to the previous altitude restr issued by approach control. On base at 1900 ft MSL, the control tower asked if we had been issued an altitude restr. I added power and stopped the descent rate of the aircraft. The captain answered, we had been issued a 2500 ft restr but felt the subsequent clearance for the visual approach by the tower had rescinded that restr. The tower responded that in the future, we must maintain the 2500 ft restr. The remainder of the approach and landing were uneventful. The following factors contributed to this altitude deviation: 1) experience in flying into high density airports supports the concept of flying visual approachs to increase flow into and out of the airport. This translates into flying a shortened pattern, traffic separation permitting. Once cleared the visual, I conducted the safest approach, based on my experience. 2) the approach clearance, although acknowledged by both pilots, was nonstandard and let ultimately to confusion as to the interpretation of the '2500 ft restr' and 'cleared the visual approach' by the tower. 3) as the PF, I could have compensated for the 2500 ft altitude restr by planning a longer final at a minimum of 8 NM from the airport to provide for a standard 300 ft per NM descent angle. 4) if restrs for noise abatement exist at an airfield where visual approachs are conducted, they should be depicted on a visual approach plate for the runway. None exist fore runway 22. This altitude deviation could have been prevented if the PF would have asked the captain to confirm the altitude restr with the tower when the question of the altitude restr was discussed in the cockpit on base leg, rather than accepting the captain's interpretation. Supplemental information from acn 292916: lga approach issued nonstandard clearance for a visual approach to runway 22 as we flew on downwind east of the field at 3000 ft MSL. 'Cleared for a visual approach to runway 22 -- do not descend below 2500 ft until on final or when cleared by tower.'

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Original NASA ASRS Text

Title: LGT DSNDS BELOW RESTR ALT.

Narrative: VFR, NIGHT ARR INTO LGA. A LDA-ALPHA APCH TO RWY 22 WAS BRIEFED WITH THE ILS TO RWY 22 AS THE BACKUP APCH. LGA APCH CTL VECTORED US E OF THE FIELD AT 3000 FT MSL. ABEAM THE ARPT, APCH ASKED IF WE HAD THE FIELD IN SIGHT. WE RESPONDED POSITIVELY AND WERE GIVEN CLRNC TO DSND TO 2500 FT AND CLRED THE VISUAL APCH TO RWY 22. THE CTLR ADDED A NONSTANDARD RESTR TO NOT DSND BELOW 2500 FT UNTIL ON FINAL OR WHEN GIVEN CLRNC TO DSND BELOW 2500 FT BY THE TWR. THE AUTOPLT WAS DISENGAGED AND DSCNT BEGAN FOR 2500 FT. APCH CTL ISSUED A TA FOR ANOTHER ACFT ON FINAL RWY 22. THE TFC WAS ACQUIRED AND A FREQ CHANGE WAS MADE TO LGA TWR. TWR CONFIRMED A CLRNC FOR THE VISUAL APCH TO RWY 22. WHEN ADEQUATE SEPARATION WITH THE TFC ON FINAL WAS ENSURED, I BEGAN A L BASE AT APPROX 3.5 NM FROM THE APCH END OF RWY 22 AND A CALL WAS MADE TO THE TWR PER PREVIOUS REQUEST. THE ACFT WAS CONFIGURED WITH 2 AND THEN 5 DEG FLAPS. THE CAPT COMMENTED WE LOOKED HIGH AND CLOSE TO THE RWY AND RECOMMENDED EXTENDING THE LNDG GEAR AND EXPEDITING THE DSCNT. I ANGLED THE ACFT SLIGHTLY AWAY FROM THE RWY AND SAID I UNDERSTOOD OUR CLRNC TO BE 2500 FT, UNTIL CLRED LOWER. THE CAPT SAID SINCE WE WERE CLRED FOR THE VISUAL APCH BY THE TWR, THERE WAS NO LONGER AN ALT RESTR. THAT MADE SENSE TO ME, DESPITE MY AWARENESS TO THE PREVIOUS ALT RESTR ISSUED BY APCH CTL. ON BASE AT 1900 FT MSL, THE CTL TWR ASKED IF WE HAD BEEN ISSUED AN ALT RESTR. I ADDED PWR AND STOPPED THE DSCNT RATE OF THE ACFT. THE CAPT ANSWERED, WE HAD BEEN ISSUED A 2500 FT RESTR BUT FELT THE SUBSEQUENT CLRNC FOR THE VISUAL APCH BY THE TWR HAD RESCINDED THAT RESTR. THE TWR RESPONDED THAT IN THE FUTURE, WE MUST MAINTAIN THE 2500 FT RESTR. THE REMAINDER OF THE APCH AND LNDG WERE UNEVENTFUL. THE FOLLOWING FACTORS CONTRIBUTED TO THIS ALTDEV: 1) EXPERIENCE IN FLYING INTO HIGH DENSITY ARPTS SUPPORTS THE CONCEPT OF FLYING VISUAL APCHS TO INCREASE FLOW INTO AND OUT OF THE ARPT. THIS TRANSLATES INTO FLYING A SHORTENED PATTERN, TFC SEPARATION PERMITTING. ONCE CLRED THE VISUAL, I CONDUCTED THE SAFEST APCH, BASED ON MY EXPERIENCE. 2) THE APCH CLRNC, ALTHOUGH ACKNOWLEDGED BY BOTH PLTS, WAS NONSTANDARD AND LET ULTIMATELY TO CONFUSION AS TO THE INTERP OF THE '2500 FT RESTR' AND 'CLRED THE VISUAL APCH' BY THE TWR. 3) AS THE PF, I COULD HAVE COMPENSATED FOR THE 2500 FT ALT RESTR BY PLANNING A LONGER FINAL AT A MINIMUM OF 8 NM FROM THE ARPT TO PROVIDE FOR A STANDARD 300 FT PER NM DSCNT ANGLE. 4) IF RESTRS FOR NOISE ABATEMENT EXIST AT AN AIRFIELD WHERE VISUAL APCHS ARE CONDUCTED, THEY SHOULD BE DEPICTED ON A VISUAL APCH PLATE FOR THE RWY. NONE EXIST FORE RWY 22. THIS ALTDEV COULD HAVE BEEN PREVENTED IF THE PF WOULD HAVE ASKED THE CAPT TO CONFIRM THE ALT RESTR WITH THE TWR WHEN THE QUESTION OF THE ALT RESTR WAS DISCUSSED IN THE COCKPIT ON BASE LEG, RATHER THAN ACCEPTING THE CAPT'S INTERP. SUPPLEMENTAL INFO FROM ACN 292916: LGA APCH ISSUED NONSTANDARD CLRNC FOR A VISUAL APCH TO RWY 22 AS WE FLEW ON DOWNWIND E OF THE FIELD AT 3000 FT MSL. 'CLRED FOR A VISUAL APCH TO RWY 22 -- DO NOT DSND BELOW 2500 FT UNTIL ON FINAL OR WHEN CLRED BY TWR.'

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.