An A320 flight crew; caught up in autoflight manipulation and company mandated airport procedural requirements; descended below the glide slope towards terrain triggering low altitude alerts from both Approach Control and the Tower.

2011-07 · NASA ASRS report 961669

Date: 2011-07 · Aircraft: A320 · Phase: approach

Anomalies: deviation-altitude-excursion-from-assigned-altitude|deviation-discrepancy-procedural-published-material-policy|inflight-event-encounter-cftt-cfit|inflight-event-encounter-unstabilized-approach

Synopsis

An A320 flight crew; caught up in autoflight manipulation and company mandated airport procedural requirements; descended below the glide slope towards terrain triggering low altitude alerts from both Approach Control and the Tower.

Narrative

As pilot flying I briefed and prepared for the LDA-A at LGA. ILS 22 was also briefed and loaded in the secondary route. New York Approach said to expect a visual approach to Runway 22. On base leg with field at in sight at 2;000 FT we were cleared for a visual approach to 22. At this time I called for the secondary approach to be activated. Outer Marker COHOP on LDA-A is 1;600 FT; Outer Marker GREKO on ILS 22 is 1;900 FT. In the transition to the visual (backed up by the ILS 22) I thought I needed to cross GREKO at 1;600 FT; placing the aircraft high on profile. I selected -1;800 FT/minutes Vertical Speed to intercept glide slope from above. As the Captain cross-checked he realized the aircraft was low on profile. At that time (approximately 1;600 FT) I disconnected the auto pilot; arrested the descent; and maintained level flight until re-intercepting the glide slope (at approximately 1;400 FT); and landed normally. Approach Control and LGA Tower informed us they received a low altitude alert. Spend more time flying the aircraft and less time managing the automation. Had I tracked the LDA-A course and flown a Visual Approach it would have eliminated a high work load in a time compressed situation.

Second reporter narrative

I (pilot not flying) went to the MCDU and activated the secondary route. I then received a message that there was an ILS/RWY mismatch. This was due to the fact that; per the airport briefing page; we were to hard tune the LDA frequency in the RAD/NAV page for the LDA-A approach. I selected the RAD/NAV page in the MCDU and deleted the LDA IDENT/FREQ and then the ILS information automatically displayed.I [then] noticed that we were at approximately 1;600 MSL and descending. I alerted the First Officer that he was low and then noticed that the speed was approaching flap overspeed. I advised 'watch your speed; you're fast'. At this point the First Officer disconnected the autopilot; leveled and slowed the aircraft; and we intercepted the glide slope from below.I didn't remember if approach had handed us over to the Tower so I queried approach if he wanted us to to go the Tower? His reply; after a short moment; was to ask if we were still with him. He said he had a low altitude alert and to contact the Tower. After I switched to Tower frequency; the Controller said that he'd been trying to contact us and that he had had a low altitude alert and that we had been too low.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.

Loading the flight search…

Frequently asked questions

How do I search flights by aircraft type on FlightFinder?

Pick an aircraft model — Boeing 737, Airbus A320, A380, Boeing 787 Dreamliner and more — enter your origin airport, and FlightFinder shows every route that plane flies from there with live fares.

Which aircraft types can I filter by?

We support Boeing 737/747/757/767/777/787, the full Airbus A220/A319/A320/A321/A330/A340/A350/A380 family, Embraer E170/E175/E190/E195, Bombardier CRJ and Dash 8, and the ATR 42/72 turboprops.

Is FlightFinder free to use?

Search and schedules are free. Pro ($4.99/month, $39/year, or $99 one-time lifetime) unlocks the enriched flight card — on-time stats, CO₂ per passenger, amenities, live gate & weather — plus My Trips with push alerts.

Where does the route data come from?

Live schedules come from Amadeus, AeroDataBox and Travelpayouts. Observed routes (which aircraft actually flew a given city pair) are crowdsourced from adsb.lol ADS-B data under the Open Database License.