We are often too quick to blame air disasters on aging of the aircraft. The true age of an aircraft is measured more by the number of take-offs and landings which is translated into life cycles rather than the number of years in operation. The Airframe primary structure suffers its greatest wear and tear during takeoff and landing. Two similar aircraft - one of which is used for regional or domestic flights will age faster than the other which is used exclusively for international flights because the latter makes fewer takeoffs and landings. The environment in which an aircraft is operated is also a factor. For instance, an aircraft that flies over sea water frequently will be subjected to corrosion fatigue from the effect of salt in the sea. Thus, operators of such aircraft are advised to have more frequent inspection of the airframe, and to take necessary corrective and/or preventive action when a scratch or corrosion is observed. Fatigue cracks start as small scratch or flaw which we sometimes have the tendency to ignore. Every time a plane lands it is thoroughly inspected for any suspect scratch. If any is observed, it is quickly taken care of to prevent it from further developing into a fatigue crack. In the late eighties or early nineties, a Hawaiian airlines plane flying between islands had its top unexpectedly blown open in mid flight. Fortunately, the experienced Pilot was able to get the plane down safely suffering only one fatality. Investigation later showed that this was due to corrosion fatigue from frequent flights over sea water. Clearly, this was a case of human error as some little cracks or corrosion signs should have been discovered when they were small if required walk around inspections had been carried out properly. During the assembly of aircraft, assembly line workers are not allowed to wear any jewelry on their fingers or around their neck or anywhere around their body to prevent, among other things, accidentally or otherwise scratching any of the structural parts used for the assembly.
The Dana Airlines Aircraft MD83 (a stretched version of the old DC 8) involved in the latest accident, first sold in 1990, about the same time the current Air Force One went into operation is not considered old by industry standard. Early reports on the Dana accident suggest an engine problem when the Pilot made a distress call to the tower about 11 miles to the destination runway, and finally crashed about two miles to the runway. Unless both engines fail at the same time, or one of the engines falls off, (which is highly unlikely, but not impossible), aircraft are designed, (as required by FAA), to be able to carry on with one surviving engine and land at nearest airport. During the civil war in Angola, a DeHavillan Hawker 800 Aircraft had one of its two engines blown up. The pilot, unaware he had been shot but noticed the engine had quit simply turned the disabled engine off and continued on to his destination, landing without a hitch. He later found out he had been shot after he got off and looked at the engine. In the summer of 1979, a DC 10, upon taking off at the Chicago O'Hair airport had its left engine detached from the wing, ricocheted across and hit the right engine knocking that one off too, resulting in one of the most disastrous accidents in US history. DC 10 is a three engine wide body aircraft with the third engine embedded in the vertical tail. If the LHS engine had merely quit, and didn't fall off or knock the other engine off, the pilot would have had a chance to return to the airport. Investigation later revealed that the left engine had been taken down for some minor repairs. The mechanic on reattaching it neglected to tighten the attachment screws properly. Among other changes, this incident forced McDonald Douglas Aircraft to reconsider the way it names its planes - from "DC" to "MD", a tactic to erase the negative image from the minds of travelers, as travelers became reluctant to fly anything associated with the initials "DC". I say all this to demonstrate that an aircraft doesn't fall off the sky because of one thing going wrong, it has to be a series of things. The Aircraft Airframe primary structural design has a lot of redundancy built into it such that if one system fails, there is another one ready to pick up the load. Perhaps one system that does not have a back up is the landing gear system, but pilots have been given adequate training in "Belly Landing" in the unfortunate event that the gears fail to deploy. Recently, one such landing was successfully carried out by a Pilot some where in Eastern Europe, I believe Romania. .
Rather than focus on the age of the aircraft, attention should be focused on the maintenance record of this particular aircraft and the responsibility or the lack there of, of the regulatory bodies that govern the airline industry in Nigeria. Statistics have shown that close to 98% of aircraft accidents occur due to human error. This includes pilot error, poor maintenance, or the lack of it. Looking through a list of Nigerian Airlines and average age of their fleet provided by a colleague from Nigeria, I was shocked to notice that some airlines have 1 aircraft fleet - Air Tarawa and Axiom. There is a type of service recommended by manufacturers called "Tear Down Inspection" (or D check as it is sometimes called) whereby the aircraft is opened up from the inside and all the structural components - frames, stringers, spars, ribs, etc- are closely inspected. This check occurs every 7 or 8 years depending on the manufacturer or the Aircraft type. If any structural damage is observed, that part is repaired or replaced. This procedure takes from 45 to 60 days, after which the aircraft is almost as good as new. Will Axiom or Air Taraba part with its only aircraft for 60 days without any income? My guess is the answer is "NO". That means they will continue to operate the only aircraft without the recommended maintenance. How did NCAA give these airlines operation permit? The MD83 first sold to Alaska Airlines in 1990 was probably D-checked at least twice before selling to Dana in 2005. It is just about due for another one. Do we know if Dana did this before the accident?. When Alaska Airlines sold this aircraft, it was for age reason. Alaska made a business decision to replace all its MD83 with the more fuel efficient and technically more advanced Boeing 737-800. This is a common practice in the industry. Another common practice is that after about 3 or 4 D-checks, an airline more not consider it economically viable to keep it because of the high cost of D check. A D check can cost in the millions depending on type of aircraft.
While we await the results of the investigation of this accident, I'll like to suggest NCAA consider doing the following to keep the airspace safe, most of which are currently in force here in the US:
1. Establish a minimum number of aircraft requirement for a new Airline and set a limit to the number of flights until the Airline establishes a good track record as to on time departure, up to date maintenance/service record, and others.
2. Require that each Airline keep a maintenance/service log on each Aircraft to be duly signed by a certified A & P (Airframe and Power Plant) mechanic from a reputable service/maintenance centre.
3. Require that each Airline have a minimum number of certified A & P mechanics on its staff
4. NCAA should make un announced visits to Airline headquarters and demand to see the maintenance log on each of the Aircraft. Ground any aircraft that lacks the proper service maintenance, and publish the results of your visit for the public to see.
5. Establish a satellite NCAA office at every Airport where NCAA staff can monitor and record on time departure/arrival for each airline, and publish the results on a monthly basis.
6. NCAA should be given power to levy a heavy fine on any Airline that cancels a scheduled flight for reasons other than safety related ones beyond its control and/or make the airline compensate stranded passengers over and above the cost of the tickets.
I had a rather bad experience this last Christmas period when I went to Nigeria for a visit. I had a reservation on a scheduled 12:00 noon Ibadan – Abuja flight on January 2nd , 2012 on Arik air that didn't take off until a little after 3:00PM. One would think that was bad, but it could have been worse. The flight from Abuja to Ibadan had been cancelled for lack of enough passengers, and though Arik had a full flight bound for Abuja, Arik was going to cancel my flight because it was going to use the same plane for my Abuja flight. With the Airport lobby overflowing with passengers, the Ibadan Arik officials convinced Abuja to send down an empty plane. This is why I am including the item 6 above. Arik in the end wasted fuel in an empty plane rather than bring the Abuja passengers no matter how few, and have that extra income. An Aircraft, when operated and serviced properly is a very safe form of transportation. With today's technology, the Aircraft industry has the tool to design against any failure mode known to man. The only failure mode we cannot design against is Act of God. I bet the results of the investigation of this accident will show that "It is NOT AGE. It is IRRESPONSIBILITY. It is GREED.
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