The officer, who cannot be named, expressed the view in an email to colleagues following the massacre on 15 March 2019.
On Friday afternoon, a lawyer for some of the victims' families, Dr Amir Bastani, shared the details of the email with the inquest into the 51 people murdered at Al Noor Mosque and Linwood Islamic Centre.
On the day of the attack, there was only one Eagle base in Auckland.
That remains the same today, one of police's most senior tactical commanders told the Coroners Court.
The email said use of the helicopter could have saved lives as it could have easily followed the terrorist's vehicle from Al Noor to Linwood.
This would have stopped tactical officers driving to various locations and some of the confusion, it said.
The tactical expert, who cannot be identified, said Eagle did respond to the attack, but there was no way it could have got to Christchurch to help in the immediate response.
The flight time was about four hours, he said.
Earlier, the Armed Offenders Squad commander said it was unlikely police could have prevented the massacre at Linwood mosque, even if they were aware of a threat against it.
The inquest earlier heard that a parliamentary staffer told a police call-taker eight minutes before the Linwood massacre that the terrorist had singled out the mosque in his manifesto.
As the shooting at Al Noor Mosque started around the same time, the call was buried, and police dispatchers and frontline officers never knew of it.
Seven people were murdered at Linwood Islamic Centre.
The AOS commander told the inquest officers were unlikely to be able to intervene, even if they had that information.
"It would've been great if they were able to - it would have been fantastic," he said.
"However, given that seven-minute timeframe - I won't use the word fanciful, but it's idealistic to think that things can come together so quickly for frontline staff to respond and be effective in that short timeframe. Seven minutes is not a great deal of time."
Once shots were reported at Linwood, it took armed officers only minutes to arrive.
Police counsel Jade Lancaster asked the senior police officer, had dispatch been aware, could anything have been done to intercept the terrorist at Linwood between the parliamentary staffer's call and the shooting beginning.
The dispatcher, Dara Taylor, previously told the court she would have immediately sent resources to the mosque to evacuate it.
The tactical expert said it was his opinion that AOS members would have "trouble" meeting that timeframe.
The first response would have had to be by frontline officers, and even if they were near the scene, they would still need time to prepare.
This would include putting on bullet-resistant armour, actioning weapons and orientating themselves with the situation and surrounding environs.
Police officers do not just jump out of the car, prepared to respond to an incident, he said.
"To drive up and not be armed or have your personal protection would be fraught with danger."
It also depended on the circumstance for what frontline staff did on arrival, the expert said.
If AOS staff were just minutes away from the scene, frontline officers would be best to wait for those with more training on entering high risk scenes.
Any clearance and evacuation would also take some time.
The tragedy involved a "heavily armed, motivated offender" who killed 51 people and injured many others across two locations within 20 minutes, the officer said.
It was "internationally unprecedented" and although the police response was not flawless, it was effective and "very likely saved many lives".
The inquest will examine the following 10 issues over seven weeks:
•Events of 15 March 2019 from the commencement of the attack until the terrorist's formal interview by police
•Response times and entry processes of police and ambulance officers at each mosque
•Triage and medical response at each mosque
•The steps that were taken to apprehend the offender
•The role of, and processes undertaken by, Christchurch Hospital in responding to the attack
•Coordination between emergency services and first responders
•Whether the terrorist had any direct assistance from any other person on 15 March 2019
•If raised by immediate family, and to the extent it can be ascertained, the final movements and time of death for each of the deceased
•The cause of death for each of the victims and whether any deaths could have been avoided
•Whether Al Noor Mosque emergency exit door in the southeast corner of the main prayer room failed to function during the attack and, if so, why?
The inquest continues.
