B737-800
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 230; Flight Crew Type 1600
Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Aircraft; Airspace Structure
I have flown out of BWI on the TERPZ 6 to either OTTTO or RAMAY the last three weeks. Each time I have flown a 737-800 or MAX8. The first two times in the 737-800 we had to adjust our climb out speed below the ECON Schedule (which was around 300) to make the 17;000ft.; or above restriction at FOXHL (FMC warnings were received 'unable next altitude'). In the 737 MAX8; it was less. So by starting early to adjust our profile we were able to meet the restriction. It appears like a trend that heavy 737-800 aircraft in summertime will have a hard time meeting the climb restriction; and if you do not catch it soon enough you may not make the FOXHL restriction.[Suggestion].In the Departure Section of the SID add a note. If departing the TERPZ 6 to OTTTO or RAMAY be aware that high gross weights and hot temperatures may not allow you to climb via the FMC ECON Speed and meet the 17;000ft.; or above restriction at FOXHL.
B737-800 First Officer reported that departing out of BWI; the aircraft is unable to make the 17000ft. restriction at FOXHL on TERPZ 6 departure.