The phrase "are normally needed" is correct and usable in written English.
It can be used when discussing requirements or necessities in a general context.
Example: "In most cases, certain resources are normally needed to complete the project successfully."
Alternatives: "are typically required" or "are generally necessary".
The canyon hike is one of Africa's most popular for good reason: five days are normally needed to complete the 88km.
A parsimonious interpretation of these data is that, while on vacation, genes that are normally needed for dealing with stress, wound healing and injury are downregulated.
Two steps are normally needed to use the District's pay-by-phone parking system: Find a legal space and check in by phone.
They avoid using protecting groups, which are normally needed to shield one part of a molecule while another segment is being transformed — a strategy that cuts the number of steps.
Bifunctional chelators are normally needed to introduce radioisotopes to nanoparticles to achieve high radiolabeling stability.
The results, reported in last week's Physical Review Letters (PRL) by a Michigan group and in the current issue of Science by an Austrian group, demonstrate that x-ray wavelengths short enough for imaging living cells can be generated with a table-top machine, although large, multimillion-dollar facilities are normally needed.
Due to the high cost and limited life span of batteries, effective energy management is normally needed to optimize the battery usage.
He said 550 people a day were normally needed at Heathrow to get people through full immigration checks in the shortest time and 584 shifts had been confirmed as covered on Heathrow's busiest day ever.
"Our position is that the Constitution sets up a structure whereby the concurrence of all three branches is normally needed in order to authorize a decisive departure from the legal status quo," the two professors write, adding: "Under the order, the executive branch acts as lawmaker, law-enforcer and judge".
About 15 Afghan archaeologists, three French advisers and 24 labourers are working at the site - a far smaller team than is normally needed.
To enhance the Raman signal from adsorbed molecules, a rough metal surface with different morphologies is normally needed for highly sensitive SERS substrates [4].
