EMB ERJ 190/195 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation - Speed All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Returned To Clearance; Flight Crew FLC Overrode Automation; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Manuals; Aircraft
Approximately an hour into flight I was given a climb from FL370 to FL380 which we were able to do based on the atmospheric conditions; aircraft performance tables; and FMS performance data. We were also given holding at ZZZ VOR. I slowed from .78 to .76 for the hold. As the aircraft entered the first turn; it was unable to maintain airspeed with the standard rate turn for a hold and the airspeed dropped to just above the low speed cue (yellow tape) and the green pitch limit indicators came up; and briefly went yellow. Because of this razor thin margin I went to heading mode which made the turn at half bank and our airspeed began to recover and we requested a lower altitude with ATC and we were given a descent to FL360 where we were able to resume the normal holding profile with no difficulties. Between the time of getting the lower altitude and flying at half bank we did leave the protected side of the hold for a short duration. The holding table in the speed/flip chart goes to FL350 but no wording as to say not to hold above that altitude and the speed and the buffet margin tables at that altitude for the bank angle and load factor showed us as within limits for our weight; we were in between 95;000-100;000 lbs and were using the 100;000 table. While we were technically still above the low speed cue the margin was too thin and not prudent to remain in that flight regimen and I felt it necessary for flight safety to intervene and use HDG which gave us half bank at that altitude until we could get a descent even though that caused us leave the hold pattern protected side for a short duration. Despite being within the buffet margin performance table-wise I would make the holding altitude limit of FL350; which is the top altitude in the holding table a hard limitation to not exceed.
EMB190 Captain reported the aircraft could not maintain Mach .76 during turns in a holding pattern at FL380. A descent to FL360 solved the problem.