Minor altitude overshoot. Discussion of TCASII procedures.

Attributes
ACN	257204
Time
Date	199311
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : fll
State Reference	FL
Altitude	msl bound lower : 10000 msl bound upper : 10080
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zma
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : instrument pilot : atp
Experience	flight time last 90 days : 201 flight time total : 12302 flight time type : 812
ASRS Report	257204
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : overshoot
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

In sum: reporter was climbing to 11000 ft. At the last min, ZMA told them to maintain 10000 ft. Reporter was able to comply but only after exceeding the assigned altitude by 80 ft. He admits they may actually have been cleared to 10000 ft in the first place. The rest of this lengthy report concerns operating procedures that actually encourage maximum rates of climb and descent until very close to the assigned altitude. He explains how this affects the TCASII and, most importantly, how 2 aircraft, 1 climbing, the other descending, could be led into a close near midair collision or a collision. The scenario is that the climbing aircraft TCASII solves the conflict by climbing through the assigned altitude. The descending aircraft is instructed to descend through the assigned altitude. If one of the pilots sees the other aircraft, he is permitted to level off but that would not prevent the other pilot from continuing climb into the conflict. He recommends that procedures be changed to mandate a reduced rate of climb/descent for the last 1000 ft.

Original NASA ASRS Text

Title: MINOR ALT OVERSHOOT. DISCUSSION OF TCASII PROCS.

Narrative: IN SUM: RPTR WAS CLBING TO 11000 FT. AT THE LAST MIN, ZMA TOLD THEM TO MAINTAIN 10000 FT. RPTR WAS ABLE TO COMPLY BUT ONLY AFTER EXCEEDING THE ASSIGNED ALT BY 80 FT. HE ADMITS THEY MAY ACTUALLY HAVE BEEN CLRED TO 10000 FT IN THE FIRST PLACE. THE REST OF THIS LENGTHY RPT CONCERNS OPERATING PROCS THAT ACTUALLY ENCOURAGE MAX RATES OF CLB AND DSCNT UNTIL VERY CLOSE TO THE ASSIGNED ALT. HE EXPLAINS HOW THIS AFFECTS THE TCASII AND, MOST IMPORTANTLY, HOW 2 ACFT, 1 CLBING, THE OTHER DSNDING, COULD BE LED INTO A CLOSE NMAC OR A COLLISION. THE SCENARIO IS THAT THE CLBING ACFT TCASII SOLVES THE CONFLICT BY CLBING THROUGH THE ASSIGNED ALT. THE DSNDING ACFT IS INSTRUCTED TO DSND THROUGH THE ASSIGNED ALT. IF ONE OF THE PLTS SEES THE OTHER ACFT, HE IS PERMITTED TO LEVEL OFF BUT THAT WOULD NOT PREVENT THE OTHER PLT FROM CONTINUING CLB INTO THE CONFLICT. HE RECOMMENDS THAT PROCS BE CHANGED TO MANDATE A REDUCED RATE OF CLB/DSCNT FOR THE LAST 1000 FT.

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.