From: email@example.com (Mark Rogers ) Organization: University of Illinois at Urbana Date: 17 Dec 93 01:52:50 PST References: 1 Followups: 1
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Marty Masters <mgm@royko.Chicago.COM> writes: (Details deleted throughout) >At ORD on last monday, a Continental flight from Texas came within a >few feet of landing on runway 27 Left without using it's landing gear. >According to a Chicago Tribune and the NTSB: >A LONG FINAL APPROACH IN HEAVY TRAFFIC: >The jet's final approach was 18-20 miles, longer than usual. >Thje TCAS was sounding alarms, indicating other traffic in the area. >The crew delayed putting the landing gear down to avoid slowing the >airplane too much. >1,500 feet: The plane brakes thru the clouds >1,000 feet: The TCAS sounds an alert, but no other plane is visible. > 500 feet: A ground proximity alarm went off. This alarm can go off >for any one of five reasons; The crew must determine the cause. The >crew, distracted by the alarms, fail to follow the landing checklist. Normal airline procedure is to respond to the GPWS, THEN determine what caused it. The five reasons, and the radio altitudes they occur at are: Altitude Reason <2450 Excessive Barometric Descent Rate <1800 Excessive Terrain Closure <500 Gear Handle not Down <200 Landing Flaps not Selected (The fifth reason would be after a go around, and less than 700 feet, when a descent of 10% of altitude occurs) >Fifty feet: The ground proximity alarm stopped. The GPWS will only sound warnings between 50 and 2450 ft (RA) >the three green landing gear lights were not lit, as the ATC >instructed them to abort the landing and circle around. As the >Captain applied full throttle to get the plane back into the air, the >rear third of the fuselage scraped the runway. >The article also adds: The flaps were extended to 25 degrees to cut >the airplane's speed. >From what I have read, this was one of the flight crews big mistakes- The flaps were left at 25 to keep the speed UP. Flaps 25 is not a legal landing flaps setting in the 727- that's why they didn't get a horn. If they had extended the flaps to 30 (a legal setting), they would have heard an unsilencable horn as the flaps passed through something like 27.5 degrees. In any event, the crew was violating regs if they were trying to land with Flaps 25. >made to avoid further aerodynamic drag on the 727. Because the flaps >were never extended to 27.5 degrees, a warning system designed to >prevent landing when the wheels are up did not activate. According to >Continental procedures: "a descent is permitted to continue after a >ground proximity warning is issued, as long as it is daytime and >visibility is clear." I suspect that Continental procedure also says something about ensuring that the airplane is properly configured, as a good part of the GPWS warnings come from incorrect configuration. From what I've seen, at least United stresses to always follow a GPWS warning. My experience is pretty limited: I'm currently a CFI at U of Illinois, and I worked as an Intern for United this past summer in Miami. As part of the Internship, I went through United's 727 Groundschool in Denver, and have about 20 or so hours in United's 727 sims. My father is a 727 Captain for United in Chicago, and I've talked with him about this incident. I also have ridden in the jumpseats of numerous 727s. I think there is at least one United Pilot who reads this group (San Fran based?)- I would be interested to hear what you think about the incident, training, etc. >There is more in the article about how the TCAS causes confusion in >the crowded O'Hare airspace ... I think TCAS is getting a bad rap in this case. From riding on jumpseats, I have seen that getting TCAS Traffic Advisories in Terminal areas is not at all uncommon. If this really was a "seasoned crew", they should not at all have been overly distracted by the TCAS calls. In any event, they were setting themselves up for the situation by landing with an illegal flaps setting, and disregarding the GPWS. -Mark These are all just my opinions- I don't even have an employer to have opinions for! (see the same discussion on rec.aviation.misc) :) >...Marty firstname.lastname@example.org >Chicago Il... The city where the rivers leak and the bridges fall up.