BBC News
watch One-Minute World News
Last Updated: Tuesday, 6 December 2005, 19:11 GMT
Iran air safety hit by sanctions
A British RAF C-130 Hercules aircraft
The C-130, known as the Hercules, is used all over the world

A generation of international isolation has undermined safety standards within Iran's civil and military aviation fleet, experts say, increasing the likelihood of major air disasters.

The C-130 transport plane which has crashed into a residential area of Tehran came down less than three years after the country's worst-ever air disaster.

In February 2003 a Russian-built Ilyushin Il-76 transporter plane crashed in south-east Iran, killing 302 passengers and crew.

Two decades of sanctions by the West against Tehran have left the country with a fleet of mainly ageing planes, often fitted with unofficial spare parts.

"The problem is likely to be one of maintenance," Chris Yates, an aviation safety expert with Jane's Transport, told the BBC News website.

Although the Lockheed Martin C-130 is in regular service around the world, most of Iran's ageing fleet was purchased in the days of the Shah, before the Islamic revolution led to cuts in ties to US companies.

"Given that Iran operates under sanctions of various types, we understand that it has difficulty obtaining spare parts direct from the manufacturer, as it is very difficult for Lockheed to do business in Iran," Mr Yates said.

With a lack of spares for newer aircraft, Mr Yates suggested, Iran may be having to source parts on an unreliable black market.

An Ilyushin Il-76, the type of plane reported to have crashed
The Il-76, which crashed in 2003, was designed in the late 1960s
Others have claimed that military engineers sometimes "cannibalise" parts from older aircraft in an effort to keep newer models in the air.

"If that is the case then they may well have put aircraft in the air with faults. That leads to this kind of accident," Mr Yates said.

Most air crashes are attributed to one or more of three main factors: poor maintenance, poor weather (the most common reason for a crash) or pilot error.

Mr Yates played down suggestions that poor visibility in Tehran due to smog may have contributed to the crash.

"Any decent pilot, when faced with a tower block looming in front of him, would do his utmost to swerve away from it," he said.

"It would seem from what I've have seen in this case that the pilot completely lost control of the ability to steer the aircraft."

Trade embargo

Since Iran's Islamic revolution of 1979, trade embargoes by Western nations have forced Iran to buy mainly Russian-built planes to supplement an existing fleet of Boeings and other American and European models.

Feb 04: Iranian plane crashes near Sharjah airport in UAE, killing 43 people
Feb 03: Military transport aircraft crashes in southern Iran, killing 302 people
Dec 02: Commuter plane carrying aerospace experts crashes in Iran, killing 46 people
Feb 02: Tu-154 operated by Iran Air crashes in mountains in west of Iran, killing 117 people
March 97: 80 die when a military plane crashes in north-east Iran
Feb 93: Tu-154 crashes into a military plane near Tehran, killing 132
A lack of spare parts was blamed for the Ilyushin disaster in 2003, which killed 284 members of Iran's elite Republican Guard and 18 crew, .

The Ilaircraft was a four-engined model originally designed in the late 1960s, which undertook its maiden flight in 1971.

After another Russian-made plane, a civilian Tupolev-154, crashed in south-western Iran in February 2002 with the loss of all 119 on board, Iranian authorities declared all its Russian-built aircraft grounded.

However, this edict appears to have been widely ignored.

Heavy-lift transport aircraft built by Lockheed Martin, known as the Hercules in the UK
Iran has some 15 C-130 E and H types dating from the mid 1970s
A modern US variant is the AC-130 - a heavily armed gunship version - used in Iraq and Afghanistan
First flew: 1956
Max. take off weight: 69,750kg
Engines: 4 Allison turboprops
Range: 2,356 miles

Source: FAS/GlobalSecurity

Many killed in Tehran plane crash
06 Dec 05 |  Middle East
In pictures: Tehran plane crash
06 Dec 05 |  In Pictures
No survivors in Iran plane crash
20 Feb 03 |  Middle East
Iran plane crash victims found
24 Dec 02 |  Middle East
Iran plane crash kills 117
12 Feb 02 |  Middle East
Country profile: Iran
28 Dec 02 |  Country profiles
Air disasters timeline
23 Oct 05 |  Europe

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Americas Africa Europe Middle East South Asia Asia Pacific