Pressed by ATC to accelerate due to traffic behind and to descend via step clearances the flight cre...

Narrative:

Descending on the lzard six arrival into tampa we were told to increase speed to 300 knots or better. There was a B737 behind us. After crossing jayja at FL270 approach asked us to descend to FL180; then 16;000 feet; then 15;000 feet. We complied. Before leveling at 15;000 feet we were asked to cross olene at 13;000 feet and 250 knots. Olene is depicted as an 'expect' at 13;000 feet and 250 knots landing south. We acknowledged the request and took immediate action but soon realized that this was outside of safe operating limits. After programming a vertical direct to olene at 13;000 feet we got the scratch pad message over maximum/vertical meaning the descent angle we had asked for was more than 6 degrees. We did our best to comply with the restriction in a safe manner but were unable to notify approach before reaching the fix. The B737 behind us; given the same instruction; also unable to comply; was telling approach the same thing that we wanted to tell them; 'unable.' after crossing the fix we explained that we had done our best and approach acknowledged that we had been 'close enough.' clearly the approach controller made a mistake. Slowing the B737 down would have been safer than asking us to speed up.

Original NASA ASRS Text

Title: Pressed by ATC to accelerate due to traffic behind and to descend via step clearances the flight crew of an EMB-175 was unable to make ATC's assigned crossing restriction of 13;000 and 250 KTS at OLENE on the LZARD STAR to TPA.

Narrative: Descending on the LZARD SIX Arrival into Tampa we were told to increase speed to 300 knots or better. There was a B737 behind us. After Crossing JAYJA at FL270 approach asked us to descend to FL180; then 16;000 feet; then 15;000 feet. We complied. Before Leveling at 15;000 feet we were asked to cross OLENE at 13;000 feet and 250 knots. OLENE is depicted as an 'Expect' at 13;000 feet and 250 knots landing south. We acknowledged the request and took immediate action but soon realized that this was outside of safe operating limits. After programming a vertical direct to OLENE at 13;000 feet we got the scratch pad message OVER MAX/VERT meaning the descent angle we had asked for was more than 6 degrees. We did our best to comply with the restriction in a safe manner but were unable to notify approach before reaching the fix. The B737 behind us; given the same instruction; also unable to comply; was telling approach the same thing that we wanted to tell them; 'unable.' After crossing the fix we explained that we had done our best and approach acknowledged that we had been 'close enough.' Clearly the Approach Controller made a mistake. Slowing the B737 down would have been safer than asking us to speed up.

Data retrieved from NASA's ASRS site 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	1182173
Time
Date	201406
Local Time Of Day	0601-1200
Place
Locale Reference	TPA.Airport
State Reference	FL
Environment
Flight Conditions	Marginal
Aircraft 1
Make Model Name	EMB ERJ 170/175 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR LZARD SIX
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance

Pressed by ATC to accelerate due to traffic behind and to descend via step clearances the flight crew of an emb-175 was unable to make ATC's assigned crossing restriction of 13;000 and 250 KTS at olene on the lzard STAR to tpa.