CALLBACK CALLBACK
From NASA's Aviation Safety Reporting System
Number 281
February 2003
FMC - Getting Along with the Program
The benefits of cockpit automation in the operation of complex aircraft have been well established. However, incidents continue to occur in which flight crew management of one or more aspects of the automated system is implicated. NASA/ASRS receives several reports each day on anomalies associated with the Flight Management Computer (FMC). The majority of these involve flight crew programming errors or a lack of familiarity with FMC response to certain inputs. In an effort to increase awareness of these errors, all of the reports discussed in this issue of Callback are related to the most common FMC problems reported to ASRS. that while programming the FMC, a discontinuity appeared somewhere in the departure. When it was closed, some waypoints were dropped. This is how we got off course... I should have done a more complete check of the First Officer’s programming.
Frequently Missed Crossings
When a runway entered in the FMC is changed, the computer may drop out previous altitude restrictions. Changing any portion of a route in the FMC requires that the Legs Page(s) be checked to ensure that each waypoint and crossing restriction is correct. Two A320 crews and a B757 crew related their experiences to ASRS. s ...The crossing restriction for the arrival was inserted into the FMC. The First Officer was flying. I left the ATC frequency to get the ATIS while we were still at cruise altitude... I informed the First Officer of the runway in use. He inserted the new runway in the FMC. Soon thereafter he received the anticipated crossing restriction and started to descend not realizing that the crossing restriction had dropped out of the FMC. The FMC vertical descent path would now be about 2000 feet high. When I came back from getting the ATIS, gate assignment, etc., I saw that we were high, brought it to the First Officer’s attention, and told him to descend as quickly as possible. I believe we were about 600 feet high crossing the fix... s The First Officer had set the bottom altitude of the Alpha Arrival and Runway 25L as the landing runway. The descent profile is built into the Arrival. There was a change in runways to 24R. When the new runway was selected, the descent profile altitude dropped out. We did not catch this. The aircraft was on descent and had reached 12,700 feet MSL when Approach Control called to ask our altitude. This was approximately two miles short of BRAVO Intersection. The BRAVO restriction is at or above 14,000 feet MSL. We stopped at 12,000 feet MSL to meet the next restriction. s On the Alpha Arrival into XXX, we crossed INTXN-1 at 17,000 feet and then got a runway change and a frequency change. We put the new runway in the FMC and it dumped all the arrival waypoints causing us to miss the crossing restriction of 16,000 feet at INTXN-2. [We were] preoccupied with the FMC, the runway assignment and frequency changes, and the FMC dump simultaneously. We did not have good CRM, and we needed to have VOR back up...
First, Make Comparisons
This B737-800 crew detailed the consequences of failing to compare the flight plan route with the FMC Legs Page(s) data. Their experience was typical of many incidents reported to ASRS in which fixes either were not entered, or were “dropped” by the computer. s [We] departed XXX on the RNAV Departure. After flying over INTXN-1, we started to fly directly to INTXN-3. We failed to fly over INTXN-2, or the ABC VOR. It wasn’t until Center informed us, that we realized we were off course ...and it took us a couple of minutes to figure out what had happened. ATC vectored us back onto the departure and gave us a climb clearance. ATC also pointed out traffic, but we never saw it. We are not sure if our error caused, or would have caused, a conflict. The First Officer programmed the FMC. I checked the Route Page to see if it matched our clearance, and it did. It showed the correct departure and transition. I did not check the Legs Pages to see if all the fixes were there. I will next time! I do not know how the two fixes got dropped, but they did, and as a result we got off course... We made an error programming the FMC, then became complacent. We assumed that once we selected LNAV that the aircraft would fly the correct route. Unfortunately the old saying applies, “Garbage in garbage out.” The airplane did exactly what we told it to do. After further reflection on this incident, it is my belief
ASRS Recently Issued Alerts On…
MD80 galley door skin damage DA20-C1 fuel contamination incident Western airport runway incursion incident Aircraft cleared for visual approach in IMC CFM-56 weather-related fan blade damage
A Monthly Safety Bulletin from
The Office of the NASA Aviation Safety Reporting System, P.O. Box 189, Moffett Field, CA 94035-0189 http://asrs.arc.nasa.gov/
January 2003 Report Intake
Air Carrier / Air Taxi Pilots General Aviation Pilots Controllers Cabin/Mechanics/Military/Other TOTAL 2053 583 17 129 2782
飞行翻译公司 www.aviation.cn 本文链接地址：美国ASRS安全公告CALLBACK cb_281.pdf
From NASA's Aviation Safety Reporting System
Number 281
February 2003
FMC - Getting Along with the Program
The benefits of cockpit automation in the operation of complex aircraft have been well established. However, incidents continue to occur in which flight crew management of one or more aspects of the automated system is implicated. NASA/ASRS receives several reports each day on anomalies associated with the Flight Management Computer (FMC). The majority of these involve flight crew programming errors or a lack of familiarity with FMC response to certain inputs. In an effort to increase awareness of these errors, all of the reports discussed in this issue of Callback are related to the most common FMC problems reported to ASRS. that while programming the FMC, a discontinuity appeared somewhere in the departure. When it was closed, some waypoints were dropped. This is how we got off course... I should have done a more complete check of the First Officer’s programming.
Frequently Missed Crossings
When a runway entered in the FMC is changed, the computer may drop out previous altitude restrictions. Changing any portion of a route in the FMC requires that the Legs Page(s) be checked to ensure that each waypoint and crossing restriction is correct. Two A320 crews and a B757 crew related their experiences to ASRS. s ...The crossing restriction for the arrival was inserted into the FMC. The First Officer was flying. I left the ATC frequency to get the ATIS while we were still at cruise altitude... I informed the First Officer of the runway in use. He inserted the new runway in the FMC. Soon thereafter he received the anticipated crossing restriction and started to descend not realizing that the crossing restriction had dropped out of the FMC. The FMC vertical descent path would now be about 2000 feet high. When I came back from getting the ATIS, gate assignment, etc., I saw that we were high, brought it to the First Officer’s attention, and told him to descend as quickly as possible. I believe we were about 600 feet high crossing the fix... s The First Officer had set the bottom altitude of the Alpha Arrival and Runway 25L as the landing runway. The descent profile is built into the Arrival. There was a change in runways to 24R. When the new runway was selected, the descent profile altitude dropped out. We did not catch this. The aircraft was on descent and had reached 12,700 feet MSL when Approach Control called to ask our altitude. This was approximately two miles short of BRAVO Intersection. The BRAVO restriction is at or above 14,000 feet MSL. We stopped at 12,000 feet MSL to meet the next restriction. s On the Alpha Arrival into XXX, we crossed INTXN-1 at 17,000 feet and then got a runway change and a frequency change. We put the new runway in the FMC and it dumped all the arrival waypoints causing us to miss the crossing restriction of 16,000 feet at INTXN-2. [We were] preoccupied with the FMC, the runway assignment and frequency changes, and the FMC dump simultaneously. We did not have good CRM, and we needed to have VOR back up...
First, Make Comparisons
This B737-800 crew detailed the consequences of failing to compare the flight plan route with the FMC Legs Page(s) data. Their experience was typical of many incidents reported to ASRS in which fixes either were not entered, or were “dropped” by the computer. s [We] departed XXX on the RNAV Departure. After flying over INTXN-1, we started to fly directly to INTXN-3. We failed to fly over INTXN-2, or the ABC VOR. It wasn’t until Center informed us, that we realized we were off course ...and it took us a couple of minutes to figure out what had happened. ATC vectored us back onto the departure and gave us a climb clearance. ATC also pointed out traffic, but we never saw it. We are not sure if our error caused, or would have caused, a conflict. The First Officer programmed the FMC. I checked the Route Page to see if it matched our clearance, and it did. It showed the correct departure and transition. I did not check the Legs Pages to see if all the fixes were there. I will next time! I do not know how the two fixes got dropped, but they did, and as a result we got off course... We made an error programming the FMC, then became complacent. We assumed that once we selected LNAV that the aircraft would fly the correct route. Unfortunately the old saying applies, “Garbage in garbage out.” The airplane did exactly what we told it to do. After further reflection on this incident, it is my belief
ASRS Recently Issued Alerts On…
MD80 galley door skin damage DA20-C1 fuel contamination incident Western airport runway incursion incident Aircraft cleared for visual approach in IMC CFM-56 weather-related fan blade damage
A Monthly Safety Bulletin from
The Office of the NASA Aviation Safety Reporting System, P.O. Box 189, Moffett Field, CA 94035-0189 http://asrs.arc.nasa.gov/
January 2003 Report Intake
Air Carrier / Air Taxi Pilots General Aviation Pilots Controllers Cabin/Mechanics/Military/Other TOTAL 2053 583 17 129 2782
飞行翻译公司 www.aviation.cn 本文链接地址：美国ASRS安全公告CALLBACK cb_281.pdf
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