A B737-800 crew reported that their aircraft was unable to comply with the mroc runway 07 poas 3 dep...

Narrative:

This comes under the heading of unable to comply with procedure. We were doing the poas 3 departure procedure from mroc on runway 07. We performed a maximum energy takeoff 26K power with a run up of the engines before brake release and still were unable to meet the requirement of 5500 ft MSL by the 04 DME turn point. We had reached only 4500 ft MSL at the 4 DME point and I decided to press toward the terrain for another half mile before turning. At that time the aircraft altitude still was only 5000 ft when the procedure calls for 5500 ft. The weather was VFR and we had no conflicts otherwise but we concluded that one of two things is wrong. Either the turn restriction is supposed to be an either-or; as in start the turn at 4 DME or 5500 ft MSL; or the required climb gradient required out of sjo has been wrongly computed. We calculate the climb gradient required to be 1190 ft per NM. As it is published; this turn requirement seems to be impossible to comply with.

Original NASA ASRS Text

Title: A B737-800 Crew reported that their aircraft was unable to comply with the MROC Runway 07 POAS 3 Departure requirement to be at 5500' by 4 DME before starting the right turn.

Narrative: This comes under the heading of unable to comply with procedure. We were doing the POAS 3 Departure procedure from MROC on Runway 07. We performed a maximum energy takeoff 26K power with a run up of the engines before brake release and still were unable to meet the requirement of 5500 FT MSL by the 04 DME turn point. We had reached only 4500 FT MSL at the 4 DME point and I decided to press toward the terrain for another half mile before turning. At that time the aircraft altitude still was only 5000 FT when the procedure calls for 5500 FT. The weather was VFR and we had no conflicts otherwise but we concluded that one of two things is wrong. Either the turn restriction is supposed to be an either-or; as in start the turn at 4 DME or 5500 FT MSL; or the required climb gradient required out of SJO has been wrongly computed. We calculate the climb gradient required to be 1190 FT per NM. As it is published; this turn requirement seems to be impossible to comply with.

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.

Attributes
ACN	895011
Time
Date	201006
Local Time Of Day	1201-1800
Place
Locale Reference	MROC.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Climb Initial Climb
Route In Use	SID POAS 3
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying First Officer
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

A B737-800 crew reported that their aircraft was unable to comply with the mroc runway 07 poas 3 departure requirement to be at 5500' by 4 DME before starting the right turn.