Peter Barnes, 50, died when his helicopter hit a crane at The Tower at St George Wharf, Vauxhall, and plunged into Wandsworth Road on the morning of January 16, 2013.
Pedestrian Matthew Wood, 39, from Sutton, Surrey, was also killed as he walked to work. Twelve other people on the ground were also injured.
Mr Barnes, who was contending with poor visibility and freezing fog that morning, had been flying from Redhill Aerodrome in Surrey to Elstree in Hertfordshire but was diverted to Battersea heliport.
On the second week of the inquest, the Southwark Coroner’s Court heard from an air traffic controller known only as “Witness C” for legal reasons.
The witness told the court there was nothing unusual about the request to divert Mr Barnes to Battersea.
Prior to this request, he had noted the weather in the city was not good but the conditions at Heathrow were slightly better.
The witness offered Mr Barnes an IFR (Instrument Flight Rules) transit, which he considered “good practice”.
At 7.53am, the pilot declined, saying: “All’s fine”.
Air traffic controllers were required to complete co-ordination with the Battersea heliport prior to the aircraft coming within five miles.
The court heard the helicopter was near Vauxhall Bridge when the request was made - on the cusp of that notification zone.
Witness C said as he called Battersea, Mr Barnes indicated the visibility in his area was good. It took staff at Battersea longer than usual to answer the phone.
He said: “My options are limited in that where I hold (the aircraft) needs to be, in best as I can endeavour to do so, outside this five-mile point.”
The phone call to Battersea and the controller’s “slightly hurried” tone suggested the heliport should not be placed under pressure, the witness said.
Witness C said: “He responded in a very fast, almost incoherent manner - ‘who is he, where is he from, why does he want to come here for, we’re not the diversion airfield’ - there were quite a few quick-fire questions that suggested to me the controller was under some pressure.”
Previous witnesses have suggested the clearance granted to Mr Barnes to “hold” between Vauxhall and London Bridges was not clarified because the controller did not use the route’s specific name and the pilot did not read the instructions back.
Witness C said: “The evidence I had at the time was that the weather conditions were good. The pilot may or may not have been having difficulty.”
He agreed there was no read-back of the instructions, addng: “The judgment call was that there was a time and a place to insist on this protocol.
“I felt at the time the aircraft needed a ‘gentle touch’.
“It would be remiss of me even potentially distracting or ... challenging the pilot, who was already in difficult circumstances, on a read-back.”
Mr Barnes did not take the most direct route back to his holding area.
Witness C said: “It would be remiss of me, again, to admonish the pilot for any marginal transgression, given the circumstances.”