Date: 201902
Local time of day: 1201-1800
Location: SNA.Airport, CA
Flight conditions: IMC
Weather elements / visibility: Rain
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B LAX
ATC / advisory: TRACON SCT
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Confusion; Communication Breakdown; Situational Awareness; Troubleshooting
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Deviation - Speed All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airspace Structure; Human Factors
Primary problem: Human Factors

Narrative: Cleared for the OHSEA 1 RNAV arrival for RWY 20R; with visual approaches in use. Crew elected to load the RNAV Z 20R approach for vertical and lateral reference; but later executed an ILS to 20R due to deteriorating weather conditions at the field.First Issue:During preflight planning; crew determined using the LAX 127 degree radial and ELB 227 degree radial in FIX pages 1 and 2 to reference the LAX Class B airspace structure (LAX 10-1B in SNA reference pages). Crew noted that the way point constraints on the RNAV RNP Z RWY 20R (SNA 12-21) for MNNIE and KLIPP were 210 knots or less; which matches the depiction on the approach plate (Ball note 1:210 knots maximum at MNNIE and KLIPP). However; using the fix pages above; the crew determined that both these points are under the LAX Class B airspace; and therefore under FAR 91.117; the maximum speed for these points is 200 knots.As recommended in Departure Arrival note 2; crew placed a hard speed constraint of 200 knots at LAXBB; and changed the speed constraints at MNNIE and KLIPP to 200B (less than 200 knots) to comply with FAR 91.117. However; it is extremely disconcerting that the approach plates and the database is coded to allow for a direct violation of FAR 91.117; and that direct manual intervention is required preclude a violation of FAR's.Second Issue:During the descent phase of the flight; flight was on profile and speed with LNAV and VNAV Path. Passing SIPPP intersection; ATC directed 'After TANDY; proceed direct to KAYNN and descend via the remainder of the OHSEA 1 arrival.' Crew complied with modifying the legs page; and after TANDY; the FMS vertical path showed a sudden and considerable deviation above path. The pilot flying immediately engaged full speed brakes with idle thrust; which resulted in a 2600 FPM descent rate. Passing 11;000 ft MSL; PF (Pilot Flying) began to shallow the descent rate to get below 250 knots at 10;000 feet; and directed the PM (Pilot Monitoring) to advise ATC that we would not be able to comply with the KAYNN restriction due to the shortcut. The Controller directed the flight to 'Maintain the current rate of descent to cross KAYNN at 7;000 feet'; with the obvious implication that ATC didn't care about the speed but the altitude. The crew interjected that we were unable to exceed the maximum speed limits below 10;000 and below the LAX Class B airspace. The Controller soon switched the flight to another sector; with the discrepancies never being addressed. While the above issue regarding the published arrival was disconcerting; this Captain finds the apparent disregard of this Controller for FAR 91.117 absolutely alarming. This Controller clearly has no idea that the laws of physics are not negotiable; and that what he was asking this crew to do; in the time and space allotted; was simply not possible while remaining in compliance with basic FAR restrictions; and when the crew voiced their concerns; the Controller was unwilling to even acknowledge their concerns.The next time this Captain encounters these kind of ATC directions; he will be more directive and state in explicit terms: Unable to comply.


Second narrative: I acted as FO (First Officer) and PM (Pilot Monitoring) flying routing to SNA. While executing a clearance to descend via RDHOT.OHSEA1; SoCal Approach instructed us to proceed direct from TANDY to KAYNN; a routing that passed through Class B airspace. During the descent to be at or below 7;000 MSL at KAYNN; the PF (Pilot Flying) began to slow to 250 KIAS to comply with the airspeed restriction below 10;000 MSL. While slowing; SoCal Approach instructed us to maintain our current rate of descent of approximately 2;500 FPM. Facing the 250 KIAS speed restriction followed by a 200 KIAS maximum speed restriction once we descended below the 7;000 MSL floor of Class B airspace enroute to complying with a 5;000 MSL required altitude at LAXBB; maintaining 2;500 FPM wasn't possible. When we notified SoCal Approach; the Controller responded saying that he required that rate of descent. We responded saying that we would descend as quickly as we could while complying with the speed restrictions.Further complicating the situation is the fact that the RNAV Z Rwy 20R approach has #1 ball notes associated with the fixes MNNIE and KLIPP that state 'MAX 210 KIAS'. The B737 FMC (Flight Management Computer) has these speeds associated with that approach as well; which could easily cause crews to fly faster than the 200 KIAS speed restriction below Class B airspace.


Synopsis: B737 flight crew reported being given an instruction that would violate a FAR regarding speeds below a LAX Class Bravo airspace.