Da 900 ex first officer reports inadvertent extension of flaps during adm test while attempting to e...

Attributes
ACN	839648
Time
Date	200906
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.VOR
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Falcon 900
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Flap Control (Trailing & Leading Edge)
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 8000 Flight Crew Type 400
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Speed All Types

Narrative:

This event occurred while performing a test of the automatic descent mode (adm) on a falcon 900 ex aircraft. The adm mode will automatically descend the aircraft to 15;000 when cabin pressure is lost. The adm is very similar to an emergency descent except the speed brakes are not extended by the automation; but may be done manually by the pilot. While performing the adm test the aircraft's flaps were extended by mistake at approximately 100 KIAS above their limit airspeed. Upon landing visual inspection indicated significant damage to the flap system. The motivation for this report is to report the incident as a human factors design issue. In the falcons the flap and speed brake handles are located behind the throttles and even though they are of a different shape they are very similar in feel. I have heard of other crews deploying the flaps in error. It is my belief that the cockpit layout contributed to inadvertent deployment of the flaps.

Original NASA ASRS Text

Title: DA 900 EX First Officer reports inadvertent extension of flaps during ADM test while attempting to extend speed brakes. Flaps were over sped by 100 KTS causing significant damage; handle design and location appear to be an issue.

Narrative: This event occurred while performing a test of the automatic descent mode (ADM) on a Falcon 900 EX aircraft. The ADM mode will automatically descend the aircraft to 15;000 when cabin pressure is lost. The ADM is very similar to an emergency descent except the speed brakes are not extended by the automation; but may be done manually by the pilot. While performing the ADM test the aircraft's flaps were extended by mistake at approximately 100 KIAS above their limit airspeed. Upon landing visual inspection indicated significant damage to the flap system. The motivation for this report is to report the incident as a human factors design issue. In the Falcons the flap and speed brake handles are located behind the throttles and even though they are of a different shape they are very similar in feel. I have heard of other crews deploying the flaps in error. It is my belief that the cockpit layout contributed to inadvertent deployment of the flaps.

Data retrieved from NASA's ASRS site as of April 2012 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.

Da 900 ex first officer reports inadvertent extension of flaps during adm test while attempting to extend speed brakes. Flaps were over sped by 100 KTS causing significant damage; handle design and location appear to be an issue.