A few lucky enlisted airmen could get as much as $90,000 to re-enlist, according to the newly released selective re-enlistment bonus calculations.

Though not too many people are likely to qualify for such a whopping bonus, there are likely to be more who get as much as $72,000 to re-up.

And more people will be eligible this year than since late 2013. The number of airmen in qualifying career fields has more than tripled, from nearly 9,000 in late 2013 to roughly 28,000 this year.

Bonuses are calculated by multiplying one month of an airman's base pay by the number of years he is re-enlisting by the multiplier for his "zone," which is based on his career field and how long he has been on active duty. Airmen with between 17 months and six years of Total Active Federal Military Service are in Zone A; Zone B airmen have between six and 10 years of service; Zone C airmen have between 10 and 14 years of service. Zone E airmen — those with 18 to 20 years of service — are not eligible for bonuses.

For example:

A pararescue master sergeant who has 14 years of service, makes $4,125 a month, falls in Zone C with a 4.5 multiplier, and who re-enlists for four years, could receive a bonus of $74,250. But if the master sergeant re-enlists for six years, he could get the maximum $90,000.

A mental health services staff sergeant with five years of service, making $2,580.60 a month, would fall in Zone A with a 2 multiplier. If he re-enlists for four years, he would get $20,644.80.

A Zone A pararescue staff sergeant, also with five years and making $2,580.60 a month, would get a 7 multiplier. If he re-enlists for four years, he could get $72,256.80 — almost as much as the master sergeant in his same career field.

Bonuses for two of the newly added career fields — 2A375 advanced fighter aircraft integrated avionics and 2A574 refuel/bomber aircraft maintenance craftsmen — are targeted to a specific skill level. That skill level is "7," the fourth digit in their Air Force specialty code. Only airmen holding that specific skill level will be eligible for the bonus.

In all, 23 career fields, up from 10, are on the list released March 12 of those eligible for re-up bonuses. The 10 career fields that remained on the Air Force's selective re-enlistment bonus list after a massive 2013 cull will not see any changes to the size of their bonuses this year, according to figures released by the Air Force Personnel Center March 18.

And the three career fields that are being restored to the list after being cut in 2013 are seeing some increases, AFPC said.

The Air Force also added 10 other career fields to the list as of March 12, bringing the total number of jobs eligible for the bonuses to 23.

In its March 12 release, AFPC said the list of career fields is growing to better retain airmen in key mission areas such as maintenance, signals intelligence and mental health.

"All of these career fields are challenged to retain experienced mid-level airmen," AFPC personnel services director Col. Arch Bruns said in the release. "The FY15 SRB program will offer bonus incentives to airmen in critical and emerging career fields with high operations demands and low manning that still require attention, such as battlefield airmen, cyberspace specialties and specific maintenance career fields. These incentives will also help the Air Force retain key maintenance experience while we work F-35 maintenance manning options."

These career fields have been at or below required sustainment levels for some time, AFPC said. As a result, they were exempt from last year's voluntary force management programs, and most involuntary programs except for the Quality Force Review Board.

"SRBs are judiciously and effectively targeted to provide the most return-on-investment in both dollars and capability," Bruns said. "This allows the [Air Force] to retain airmen who are critical to current and emerging mission requirements."

Retired Col. Terry Stevens, a personnel expert, said increasing pay through the bonuses is a highly effective way for the Air Force to hold on to airmen with critical skills that it might otherwise lose to the private sector.

"When someone sees the type of money they can get [in the private sector], over what they've been getting, that's when the retention factor" becomes an issue, Stevens said. Re-enlistment bonuses are "a way to [enhance] base pay for those people the Air Force needs in chronic skills."

Stevens said the return of the 2A5X2D helicopter and tilt rotor aircraft maintenance for CV-22 Osprey, 2M0X3 missile and space facilities and 4C0X1 mental health services career fields to the list shows the Air Force recognizes it has a growing need for such airmen.

For example, he said the scandals involving cheating, drug use and poor morale among nuclear missile airmen and the Air Force's move to hold on to skilled airmen in that field likely contributed to the resumption of bonuses to them.

"When you get in enough trouble, they're going to start throwing money at it," Stevens said.

And concerns about increasing rates of post-traumatic stress and suicide among troops — especially after more than 13 years of war — probably encouraged the Air Force to once again offer bonuses to mental health airmen.

"The things people go through with [improvised explosive devices], suicide bombers, it's more traumatic than, say, what it was in Vietnam," Stevens said. "They are concerned" about mental health issues.

Stevens said he didn't think the return of those three career fields is a sign the Air Force went too far when it cut 46 jobs from the bonus list a year and a half ago.

He thinks the Air Force's decision to expand the list by 13 career fields may be a sign officials are trying to rebuild the force after a year of painful cuts.