The Nimrod which crashed had been in service since 1969
A former RAF Nimrod trial officer has questioned the suitability of the aircraft for use in Afghanistan.
His comments came after the widow of one of the 14 men killed in last month's Nimrod crash said defence cutbacks had put lives at risk.
Retired Flt Lt Jimmy Jones said the Nimrod's age, Afghan conditions and its role there were factors that could have contributed to the accident.
The Ministry of Defence defended the RAF's record in maintaining the Nimrod.
Flt Lt Jones also cast doubt on the MoD's claims that the money spent on the aircraft's maintenance had doubled.
He told BBC Scotland that Shona Beattie, whose husband Flt Sgt Stephen Beattie died when the RAF Kinloss-based plane exploded, was "quite justified" in voicing her concerns over the aircraft's maintenance.
She said her partner had told her he could not remember the last time he flew a plane "with all the parts working".
The MoD said Nimrod MR2s were maintained to the highest standards.
In a statement, it said that over the past two years the amount spent on Nimrod maintenance went up by 50% to £3m per aircraft per year.
Flt Lt Jones, who worked at Kinloss, said the aircraft had come into service in 1969 and was upgraded from a Mark One to a Mark Two.
It's a very old aircraft being sent to do a very difficult job in very extreme circumstances
SNP defence spokesman
The aircraft had a range of 3,800 miles and was originally intended for hunting submarines.
He said the Nimrod's life had been extended because of the delayed Mark Four.
Flt Lt Jones said: "Now they are being used in a rather obscure role in Afghanistan and Iraq with in-flight refuelling - carried out just before the incident - where we seem to be increasing the operational range of the aircraft up to that of the Mark Four.
He said when he was a trials engineer for the Nimrod the "hot weather" trials were held in Malta.
"We are a long way from hunting submarines in Afghanistan and it's a damn site hotter there than in Malta," he added.
Flight Sergeant Beattie was highly regarded
Twelve Kinloss-based airmen, a Royal Marine and a soldier died after a suspected technical fault.
Angus Robertson, the local MSP for the base and Scottish National Party defence spokesman, said the MoD should answer the concerns over the aircraft to reassure families.
He said: "It's a very old aircraft being sent to do a very difficult job in very extreme circumstances and we have lost a lot of lives.
"We need to get to the bottom of all these challenges as soon as possible to put people's minds at rest because we continue to send RAF crews out in this aircraft in Afghanistan and Iraq."
Is it now time to upgrade our planes? I watched the interview with Sergeant Beattie's widow and she said that her husband was prepared to die in a war but not prepared to die for a technical fault.