By Zoe Conway
BBC News, Washington
Seven of the last eight fatal commercial plane crashes in the US involved regional airlines.
Small regional airlines now operate half of all flights in America
The most recent accident, in which a Continental Connection plane crashed into a house near Buffalo, New York, left 50 people dead.
Investigators have not yet said what caused the crash, but central to their inquiry have been questions about the crew's experience, training and working conditions.
And safety experts are asking the very same questions about the regional airline industry as a whole.
Alex Lapointe loves flying, which is fortunate, because he cannot be doing it for the money.
Just 24 years old, First Officer Lapointe has been a regional airline pilot for the last three years.
Like many regional carriers - which typically operate planes carrying fewer than 100 passengers - the company he works for pays a starting salary of around $20,000 (£13,256).
Some of his young pilot friends are saddled with more than $100,000 in student loans and he says many of them have taken second jobs.
"A lot of people I know have trade jobs or construction work they do electrical work. Some still work at the airport they grew up with pumping gas or working the line - anything they can to make an extra few dollars," he says.
He thinks that the new recruits are tiring themselves out and it is having an impact on safety.
"They don't have enough time to enjoy their days off and they're constantly working - they're doing the grind 24/7. When it's the fourth leg on a heavy flying day and the first officer's flying and the captain's working the radios and there's a hundred things going on, you're going to want both people in the cockpit well rested," says First Officer Lapointe.
Fatigue has long been of concern to the National Transportation Safety Board (NTSB), the federal agency responsible for investigating plane crashes in America.
In a number of recent regional accident reports, they concluded that pilot fatigue was partly to blame:
- When a Corporate Airlines flight crashed in Kirksville, Missouri, in 2004, the NTSB said that fatigue contributed to the pilots' "degraded performance"
- It found that the captain of a Delta Connection plane which overran the runway in Cleveland, Ohio, in 2007, had slept for only one of the previous 32 hours
- When later that same year a Canadair jet overran the runway in Traverse City, Michigan, the NTSB ruled that fatigue was the likely cause of "poor decision-making"
Now the NTSB is investigating another regional accident where fatigue could have been a factor. Continental Connection Flight 3407 crashed near Buffalo, New York in February this year. All of the 49 passengers and crew on board died, as well as one person on the ground.
In the immediate aftermath of the crash, speculation focused on the idea that an ice build-up on the wings had affected the plane's performance.
Fifty died when a Continental Connection plane crashed near Buffalo
While ice has not been ruled out as a factor, the NTSB - which is holding a public hearing into the crash this week - has announced that the "circumstances of the crash have raised several issues that go well beyond the widely discussed matter of airframe icing".
They are looking at the experience and training of the crew, whether standard procedures were being followed and the issue of fatigue management.
Roger Cohen of the Regional Airline Association (the regional airlines' trade association) acknowledges that pilot fatigue is an issue but he insists it is an industry-wide problem that is not unique to the regional sector, and points to strict rules limiting pilot hours in the cockpit.
"They shouldn't be tired and that's the responsibility of anybody and the rules prevent you from being tired. Let me ask anybody else - should they come to their job tired? No they shouldn't, no-one should."
Regional airlines now operate half of all flights in America.
Their dramatic growth is in part due to the economy - as fewer passengers fly, smaller planes have become more economical.
But industry insiders have told the BBC that the regional airlines - in their rush to recruit extra staff - have hired pilots with drastically fewer flying hours.
Patrick Smith is a pilot for a major carrier and writes a weekly aviation column for Salon.com.
When he started out 20 years ago, he needed at least 1,500 flying hours to get a job at a regional airline.
Now, he says, it is common for pilots to be hired with 200-300 hours, which, he says, though legal is "astonishingly low".
And he explained that being a good pilot is about more than training.
"There's no good way to teach good judgement - only experience really can develop that," he says.
But federal officials are not just worried about low pay and inexperience.
Robert Sumwalt, a member of the board of the NTSB, is concerned that regional carriers do not have robust enough systems in place to monitor the performance of their pilots:
"When you look at the safety programmes that some of the regional carriers have, compared to what most of the major carriers have, there is a difference."
For more than a decade, safety experts have been advocating that all the airlines implement a program called Flight Operational Quality Assurance (FOQA).
Using FOQA, airline companies can check up on how everyone involved in a flight is doing and - if mistakes are occurring - develop a training system to correct them.
Following an NTSB guideline issued two years ago, almost all of the major airlines adopted the programme. But to Robert Sumwalt's dismay, only three of America's 50 regional carriers have it in place.
"Safety is not a luxury," he says. "I think that if it's good for the major carriers it needs to be good for the regional carriers and I think that the travelling public is entitled to that and furthermore they deserve it."
But Roger Cohen points out that it is a complex programme to implement and the Regional Airline Association is trying hard to put it in place:
"We've got carriers that are doing it - more are doing it every day. If we were to do this interview next week, we'd probably have more. If we do it in a month, we'd have even more... We are following all the rules."
Patrick Smith says following the rules is not enough.
Through his online column, he regularly hears from regional pilots suffering from low morale:
"I see red flags. I see very low-time pilots in hi-tech airplanes in miserable or at least unsavoury working conditions. And something needs to be done about that before there is a legacy of crashes."
At this week's NTSB Buffalo crash hearing, the issues of pilot experience, fatigue and working conditions are expected to come to the fore.
The question is: will discussion of these issues prompt change?
A TV version of this report was broadcast on
BBC World News America
on Friday 8 May.