|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : akr|
|Altitude||agl bound lower : 0|
agl bound upper : 0
|Controlling Facilities||tower : acy|
|Operator||general aviation : instructional|
|Make Model Name||Small Transport, Low Wing, 2 Recip Eng|
|Flight Phase||landing other|
|Function||instruction : instructor|
oversight : pic
|Qualification||pilot : commercial|
pilot : instrument
pilot : atp
pilot : cfi
|Experience||flight time last 90 days : 79|
flight time total : 7583
flight time type : 234
|Function||flight crew : captain|
instruction : trainee
|Qualification||pilot : commercial|
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||other flight crewa|
|Resolutory Action||none taken : detected after the fact|
|Air Traffic Incident||other|
We made multiple touch and go lndgs for the purpose of practicing engine-out procedures in the pattern. After several such lndgs, on downwind just after gear extension, I pulled the left engine to simulate an engine failure and student went through the engine failure emergency checklist from memory. Out loud he called, 'add power, mixtures forward, propellers forward, throttles forward, flaps up, gear leave down, identify, verify and feather.' I had my thumb behind the propeller control to prevent actual feather and called stop. Student then took his hand off the propeller control, back to the right throttle. I then set the left throttle at 11.5' to simulate a feathered engine. Student then called his oral final check, mixtures, propellers, flaps 3 green. I made the same check silently on short final. Earlier I was concerned with a slightly high descent rate and slow airspeed combination and gave some instructions that had student made some corrections. It was going to be a good landing. I thought I heard the mains touch but then heard the propellers hit. We slid toa stop on the runway centerline. I then reached down to turn off the fuel selectors and observed the gear handle down. There was no gear warning light and had been no oral warning. I opened the door, got out and assisted the students out. We then moved to the side of the runway. On review of the events I believe that the 5 amp circuit on our aircraft may have failed preventing the gear from extending. With the 5 amp circuit failed there would be no gear warnings and no green lights. With the bright sun that was present the gear lights can appear to be illuminated when in fact they are not. I have on several previous occasions had students make this mistake and in at least 1 such case the student continued to insist that the lights had been green even after I had extended the gear and the lights illuminated. On reflection of that I realized that the lights had been 'green' but not illuminated. To prevent future, like occurrences, our school has changed our final check to include the call 'landing gear check down' instead of '3 green' to reduce the expectation of green lights and hopefully forces a more reliable check of the gear indications. It might also reduce such incidents if the gear down lights were not green in color when not illuminated from within. Perhaps they could be made with 2 lenses, 1 yellow and 1 blue, which would show green only when lit from behind. Also it could help if the oral warning was not on the same circuit as the gear control circuit. This would reduce the changes that both the gear operation and its safety warnings would fail at the same time.
Original NASA ASRS Text
Title: TRAINING FLT INVOLVING SEVERAL LNDGS ON SIMULATED ENGINE OUT APCH AND LNDG, GEAR COLLAPSED.
Narrative: WE MADE MULTIPLE TOUCH AND GO LNDGS FOR THE PURPOSE OF PRACTICING ENG-OUT PROCS IN THE PATTERN. AFTER SEVERAL SUCH LNDGS, ON DOWNWIND JUST AFTER GEAR EXTENSION, I PULLED THE LEFT ENG TO SIMULATE AN ENG FAILURE AND STUDENT WENT THROUGH THE ENG FAILURE EMER CHKLIST FROM MEMORY. OUT LOUD HE CALLED, 'ADD PWR, MIXTURES FORWARD, PROPS FORWARD, THROTTLES FORWARD, FLAPS UP, GEAR LEAVE DOWN, IDENT, VERIFY AND FEATHER.' I HAD MY THUMB BEHIND THE PROP CTL TO PREVENT ACTUAL FEATHER AND CALLED STOP. STUDENT THEN TOOK HIS HAND OFF THE PROP CTL, BACK TO THE RIGHT THROTTLE. I THEN SET THE LEFT THROTTLE AT 11.5' TO SIMULATE A FEATHERED ENG. STUDENT THEN CALLED HIS ORAL FINAL CHK, MIXTURES, PROPS, FLAPS 3 GREEN. I MADE THE SAME CHK SILENTLY ON SHORT FINAL. EARLIER I WAS CONCERNED WITH A SLIGHTLY HIGH DSNT RATE AND SLOW AIRSPD COMBINATION AND GAVE SOME INSTRUCTIONS THAT HAD STUDENT MADE SOME CORRECTIONS. IT WAS GOING TO BE A GOOD LNDG. I THOUGHT I HEARD THE MAINS TOUCH BUT THEN HEARD THE PROPS HIT. WE SLID TOA STOP ON THE RWY CENTERLINE. I THEN REACHED DOWN TO TURN OFF THE FUEL SELECTORS AND OBSERVED THE GEAR HANDLE DOWN. THERE WAS NO GEAR WARNING LIGHT AND HAD BEEN NO ORAL WARNING. I OPENED THE DOOR, GOT OUT AND ASSISTED THE STUDENTS OUT. WE THEN MOVED TO THE SIDE OF THE RWY. ON REVIEW OF THE EVENTS I BELIEVE THAT THE 5 AMP CIRCUIT ON OUR ACFT MAY HAVE FAILED PREVENTING THE GEAR FROM EXTENDING. WITH THE 5 AMP CIRCUIT FAILED THERE WOULD BE NO GEAR WARNINGS AND NO GREEN LIGHTS. WITH THE BRIGHT SUN THAT WAS PRESENT THE GEAR LIGHTS CAN APPEAR TO BE ILLUMINATED WHEN IN FACT THEY ARE NOT. I HAVE ON SEVERAL PREVIOUS OCCASIONS HAD STUDENTS MAKE THIS MISTAKE AND IN AT LEAST 1 SUCH CASE THE STUDENT CONTINUED TO INSIST THAT THE LIGHTS HAD BEEN GREEN EVEN AFTER I HAD EXTENDED THE GEAR AND THE LIGHTS ILLUMINATED. ON REFLECTION OF THAT I REALIZED THAT THE LIGHTS HAD BEEN 'GREEN' BUT NOT ILLUMINATED. TO PREVENT FUTURE, LIKE OCCURRENCES, OUR SCHOOL HAS CHANGED OUR FINAL CHK TO INCLUDE THE CALL 'LNDG GEAR CHK DOWN' INSTEAD OF '3 GREEN' TO REDUCE THE EXPECTATION OF GREEN LIGHTS AND HOPEFULLY FORCES A MORE RELIABLE CHK OF THE GEAR INDICATIONS. IT MIGHT ALSO REDUCE SUCH INCIDENTS IF THE GEAR DOWN LIGHTS WERE NOT GREEN IN COLOR WHEN NOT ILLUMINATED FROM WITHIN. PERHAPS THEY COULD BE MADE WITH 2 LENSES, 1 YELLOW AND 1 BLUE, WHICH WOULD SHOW GREEN ONLY WHEN LIT FROM BEHIND. ALSO IT COULD HELP IF THE ORAL WARNING WAS NOT ON THE SAME CIRCUIT AS THE GEAR CTL CIRCUIT. THIS WOULD REDUCE THE CHANGES THAT BOTH THE GEAR OPERATION AND ITS SAFETY WARNINGS WOULD FAIL AT THE SAME TIME.
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.