FA50 captain acknowledges ZAU descent crossing clearance against first officer wishes. A 5000 FPM de...

Attributes
ACN	576985
Time
Date	200303
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	intersection : bearz
State Reference	IL
Altitude	msl single value : 11000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	general aviation : corporate
Make Model Name	Falcon 50
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	arrival star : n/s
Person 1
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : cfi pilot : atp pilot : multi engine
Experience	flight time last 90 days : 90 flight time total : 3000 flight time type : 476
ASRS Report	576985
Person 2
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : autoplt tripped other flight crewa
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

ZAU requested us to make bearz at 11000 ft MSL after holding us at a higher altitude. I advised the captain that it would be difficult to accomplish, yet he responded to the controller 'bearz at 11000 ft.' ord center then came back and said to do the best you can to try and make bearz at 11000 ft. The descent required in excess of 5000 FPM RAT of descent to accomplish. I initiated the descent towards 11000 ft. As I passed through 12000 ft MSL, I adjusted the autoplt's vsi rate of descent to accomplish a leveloff in a safe fashion. Unfortunately, due to the high rate of descent, the autoplt had already entered into the capture logic for 11000 ft. Due to trying to 'adjust' the vsi controller when the autoplt had already entered into the 'capture' mode, it caused the autoplt to revert to raw pitch mode. I caught it immediately, but due to the continued high rate of descent and disconnecting of the autoplt, I overshot my altitude by 200 ft. The aircraft bottomed out at 10800 ft MSL before climbing back to 11000 ft MSL. The ord controller confirmed that we were, in fact, level at 11000 ft at bearz. We, in fact were, when he made the query. I'm not sure if his query was due to an altitude warning that he received when we momentarily bottomed out at 10800 ft MSL. Regardless of the reason for the query, an important lesson was learned. Accepting a rate of descent in excess of 4500 FPM is not prudent. In our case, 5000 FPM was required to make the altitude restr. In the future, I will be more forceful with the captain and more explicit with ATC with descent parameter restraints. Additionally, I will not accept dscnts that require in excess of 4000 FPM unless an emergency or critical situation exists. It goes back to the old adage of a 'failure to plan on your part, should not constitute a crisis on my part.' don['T let ATC (or the captain) paint you into a corner. Additionally, during high rates of descent, be aware that most autoplts will enter into the 'capture' mode much earlier than you're accustomed to. Be prepared for this.

Original NASA ASRS Text

Title: FA50 CAPT ACKNOWLEDGES ZAU DSCNT XING CLRNC AGAINST FO WISHES. A 5000 FPM DSCNT CAUSES A 200 FT OVERSHOOT.

Narrative: ZAU REQUESTED US TO MAKE BEARZ AT 11000 FT MSL AFTER HOLDING US AT A HIGHER ALT. I ADVISED THE CAPT THAT IT WOULD BE DIFFICULT TO ACCOMPLISH, YET HE RESPONDED TO THE CTLR 'BEARZ AT 11000 FT.' ORD CTR THEN CAME BACK AND SAID TO DO THE BEST YOU CAN TO TRY AND MAKE BEARZ AT 11000 FT. THE DSCNT REQUIRED IN EXCESS OF 5000 FPM RAT OF DSCNT TO ACCOMPLISH. I INITIATED THE DSCNT TOWARDS 11000 FT. AS I PASSED THROUGH 12000 FT MSL, I ADJUSTED THE AUTOPLT'S VSI RATE OF DSCNT TO ACCOMPLISH A LEVELOFF IN A SAFE FASHION. UNFORTUNATELY, DUE TO THE HIGH RATE OF DSCNT, THE AUTOPLT HAD ALREADY ENTERED INTO THE CAPTURE LOGIC FOR 11000 FT. DUE TO TRYING TO 'ADJUST' THE VSI CTLR WHEN THE AUTOPLT HAD ALREADY ENTERED INTO THE 'CAPTURE' MODE, IT CAUSED THE AUTOPLT TO REVERT TO RAW PITCH MODE. I CAUGHT IT IMMEDIATELY, BUT DUE TO THE CONTINUED HIGH RATE OF DSCNT AND DISCONNECTING OF THE AUTOPLT, I OVERSHOT MY ALT BY 200 FT. THE ACFT BOTTOMED OUT AT 10800 FT MSL BEFORE CLBING BACK TO 11000 FT MSL. THE ORD CTLR CONFIRMED THAT WE WERE, IN FACT, LEVEL AT 11000 FT AT BEARZ. WE, IN FACT WERE, WHEN HE MADE THE QUERY. I'M NOT SURE IF HIS QUERY WAS DUE TO AN ALT WARNING THAT HE RECEIVED WHEN WE MOMENTARILY BOTTOMED OUT AT 10800 FT MSL. REGARDLESS OF THE REASON FOR THE QUERY, AN IMPORTANT LESSON WAS LEARNED. ACCEPTING A RATE OF DSCNT IN EXCESS OF 4500 FPM IS NOT PRUDENT. IN OUR CASE, 5000 FPM WAS REQUIRED TO MAKE THE ALT RESTR. IN THE FUTURE, I WILL BE MORE FORCEFUL WITH THE CAPT AND MORE EXPLICIT WITH ATC WITH DSCNT PARAMETER RESTRAINTS. ADDITIONALLY, I WILL NOT ACCEPT DSCNTS THAT REQUIRE IN EXCESS OF 4000 FPM UNLESS AN EMER OR CRITICAL SIT EXISTS. IT GOES BACK TO THE OLD ADAGE OF A 'FAILURE TO PLAN ON YOUR PART, SHOULD NOT CONSTITUTE A CRISIS ON MY PART.' DON['T LET ATC (OR THE CAPT) PAINT YOU INTO A CORNER. ADDITIONALLY, DURING HIGH RATES OF DSCNT, BE AWARE THAT MOST AUTOPLTS WILL ENTER INTO THE 'CAPTURE' MODE MUCH EARLIER THAN YOU'RE ACCUSTOMED TO. BE PREPARED FOR THIS.

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.

FA50 captain acknowledges ZAU descent crossing clearance against first officer wishes. A 5000 FPM descent causes a 200 ft overshoot.