A B76734-300 FLC MISTAKES MINIMUMS FOR GS OUT AT HUNDA; ON THE ILS RWY 25L APCH AT LAX. FLC DOESN'T REALIZE THE GS OUT MINIMUMS ARE A DASHED LINE ON THE APCH PROFILE.

1997-05 · NASA ASRS report 369208

Date: 1997-05 · Aircraft: B767-300 and 300 ER · Phase: approach

Anomalies: other-no-specific-anomaly-occurred|other-unspecified

Synopsis

A B76734-300 FLC MISTAKES MINIMUMS FOR GS OUT AT HUNDA; ON THE ILS RWY 25L APCH AT LAX. FLC DOESN'T REALIZE THE GS OUT MINIMUMS ARE A DASHED LINE ON THE APCH PROFILE.

Narrative

ON THE CIVET ARR TO LAX RWY 25L; WE WERE CLRED; AFTER ARNES INTXN; FOR THE ILS RWY 25L APCH. AFTER COMPLYING WITH ALT RESTRS AT SUZZI AND FUELR INTXNS; WE INTERCEPTED THE ILS GS AT GAATE (16.6 ILS DME) AT 5000 FT MSL WHICH IS THE PUBLISHED GS INTERCEPT ALT AND FIX. THE PUBLISHED APCH SHOWS THE ON THE GLIDE PATH ALT OVER HUNDA INTXN OF 3499 FT MSL. APCH CTL ADVISED US; AFTER WE HAD PASSED GAATE; TO CROSS HUNDA AT OR ABOVE 3500 FT. OUR AUTOPLTS WERE ENGAGED IN THE APCH MODE (FMS'S PROGRAMMED FOR THE APCH); COMPUTED AND RAW DATA XCHK SHOWED US ON COURSE AND ON GS. THERE WAS NO REASON TO THINK THE HUNDA RESTR WOULD BE A PROB. BY THE TIME WE REALIZED WE WERE GOING TO BE LOWER THAN THE 3500 FT RESTR AT HUNDA; IT WAS TOO LATE TO DO ANYTHING ABOUT IT SAFELY. WE CROSSED HUNDA AT 3320 FT MSL; ON GS (PUBLISHED APCH SAID 3500 FT). WE CROSSED LIMMA (7.4 ILS DME) AT 1890 FT MSL JUST AS PUBLISHED. TO TRY TO MEET THE HUNDA RESTR WOULD HAVE MEANT DANGEROUSLY UNSTABILIZING THE APCH IN IMC CONDITIONS; AT NIGHT AND UNNECESSARILY INCREASING THE WORKLOAD TO RE-ESTABLISH THE ON GS CONDITION AND RE-ENGAGING THE AUTOPLTS IN THE APCH MODE; ALL THE WHILE CONFIGURING; RUNNING CHKLISTS; COMPLYING WITH APCH CTL SPD RESTRS; RECEIVING TA'S AND FREQ CHANGE INSTRUCTIONS. 3 QUESTIONS OCCUR TO ME: 1) CAN APCH CTL ISSUE AN ALT RESTR ON AN ILS GS AFTER THE ACFT HAS A) BEEN CLRED FOR THE APCH; AND B) PASSED THE GS INTERCEPT POINT? 2) IF THE PUBLISHED PROC DOES NOT DEPICT ACCURATELY WHAT WILL OCCUR; WHY IS ITS USE PERMITTED TO CONTINUE? 3) IF COMPLYING WITH A PUBLISHED APCH PROC; FLCS RISK VIOLATING AN ALT RESTR; WHY IS THE PROC EVEN CERTIFIED? FLCS CAN DO EVERYTHING CORRECTLY AND STILL MISS AN ALT RESTR. OTHER PLACES THIS IS CALLED ENTRAPMENT. SUCH A SIT IS ABSURD AND OUTRAGEOUS. POSSIBLE SOLUTIONS: 1) STOP ISSUING THE HUNDA RESTR. 2) CHANGE THE PUBLISHED PROC. 3) SUSPEND THE ILS RWY 25L UNTIL IT HAS BEEN FLT TESTED AND CORRECTED. 4) START FROM SCRATCH AND BUILD A NEW APCH WITH NEW GND EQUIP THAT CAN RADIATE SIGNALS WHICH ALLOW ACFT TO COMPLY WITH ALL NECESSARY RESTRS.

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.