Both 188 and 189 have the same delay code according to EF, DELAY ZY, which from previous posts on here is a late incoming aircraft. That would imply a knock on delay from another flight into LHR which I believe does not count as extraordinary in terms of EU261.
Results from https://www.ExpertFlyer.com
Code:
Flight Status Search:
Departing on 13/09/17
Flying BA flight 188Flight Status Depart Location Depart Date Reliability Arrive Location Arrive Date
EWR Scheduled: 13/09/17 21:30 LHR Scheduled: 14/09/17 9:20
BA 188 En Route Term: B Estimated: 14/09/17 1:09 75% / 43m Term: 5 Estimated: 14/09/17 12:49
Gate: Actual: 14/09/17 1:09 Gate: Actual:
Comments:
"DOBA188/13SEP
* OPERATIONAL FLIGHT INFO * BA 188 -1 WE 13SEP17
CITY INFO HOUR (LOCAL)
EWR ESTIMATED TIME OF DEPARTURE 0100
LEFT THE GATE 0109
TOOK OFF 0124
DELAY ZY
ESTIMATED TIME OF ARRIVAL 1249 LHR
*1A PLANNED FLIGHT INFO* BA 188 -1 WE 13SEP17 ASM
APT ARR DY DEP DY CLASS/MEAL EQP GRND EFT TTL
EWR 2130 WE FAJCDRIWETY/M 777 6:50
BHKMLVSNQOG/M
X/M
LHR 0920 TH 6:50
X/M
COMMENTS-
1.EWR LHR - MEMBER OF ONEWORLD
2.EWR LHR - DEPARTS TERMINAL B
3.EWR LHR - ARRIVES TERMINAL 5
4.EWR LHR - 9/ NON-SMOKING
5.EWR LHR - SECURED FLIGHT
6.EWR LHR - ET/ ELECTRONIC TKT CANDIDATE
7.EWR LHR - CABIN J- SLEEPER SERVICE
8.EWR LHR - CO2/PAX* 316.67 KG ECO, 633.35 KG PRE
(*):SOURCE:ICAO CARBON EMISSIONS CALCULATOR
CONFIGURATION-
777 F 14 J 48 W 40 M 124
>"