Air Turnback

Air Turnback

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Description

An air turnback is a situation where an aircraft returns to land at the departure aerodrome without having initially planned to do so.

The most common reason for air turnback is an emergency or abnormal situation during or shortly after take-off, the most common being engine failure. If the problem happens during acceleration, the crew might attempt to reject the take off depending on the speed and the nature of emergency. Sometimes a safer option is to get airborne and then make an approach and land. A probable complication in this case is that the aircraft's current weight may be greater than the certified maximum landing weight (MLW). If the crew opts for a turnback in this case, there are three options:

  • Make an overweight landing. The pilot in command has the right to deviate from prescribed procedures as required in an emergency situation in the interest of safety, i.e. they may choose to land even though the aircraft is heavier than the MLW if they consider this to be the safest course of action. The landing will be more challenging and require longer runway, thus increasing the chance of a runway excursion. Also, a special post-landing inspection will have to be carried out.
  • Burning the excess fuel, e.g. by entering a holding pattern. This is a safe option in many cases but if it is considered that by the time the weight is reduced below the MLW the aircraft will no longer be airworthy, or there is another urgent matter (e.g. a medical emergency) another course of action will be taken.
  • Dump fuel. This option is not available for most aircraft types and even if it is, the respective system may not have been installed on the particular aircraft. Additional restrictions may also apply, e.g. a minimum level to perform the operation or the need to reach a dedicated fuel dumping area.

Air turnback may happen during all phases of the flight, e.g. climb, cruise or even when the aircraft has reached the vicinity of the destination aerodrome (but is unable to land due to weather conditions). Any significant problem with the aircraft during the climb phase is likely to result in a turnback because of the closeness of the departure aerodrome. During the cruise, if an engine fails (or annother emergency situation arises, e.g. loss of cabin pressure), the flight crew will evaluate the situation and decide on the further course of action. Depending on the circumstances (severity of the situation, available fuel, company policy, weather, etc.), the choice may be to continue to the planned destination, to divert to the planned alternate, to land at the nearest suitable aerodrome or to return to the point of departure.

Accidents and Incidents

  • DC93, en-route, north west of Miami USA, 1996 (On 11 May 1996, a DC9-30 crew were unable to keep control of their aircraft after a hold fire started in live chemical oxygen generators which had been loaded contrary to applicable regulations. The Investigation concluded that, whilst the root cause was poor practices at the maintenance contractor which handed over oxygen generators for loading in an unsafe condition, the context for this was a failure of the air carrier to effectively oversee the shipper and of the FAA to oversee the air carrier. Failure of the FAA to require fire suppression in Class 'D' cargo holds was also cited.)
  • A320, vicinity Delhi India, 2017 (On 21 June 2017, an Airbus A320 number 2 engine began vibrating during the takeoff roll at Delhi after a bird strike. After continuing the takeoff, the Captain subsequently shut down the serviceable engine and set the malfunctioning one to TO/GA and it was several minutes before the error was recognised. After an attempted number 1 engine restart failed because an incorrect procedure was followed, a second attempt succeeded. By this time inattention to airspeed loss had led to ALPHA floor protection activation. Eventual recovery was followed by a return to land with the malfunctioning engine at flight idle.)
  • B744, vicinity Dubai UAE, 2010 (On 3 September 2010, a UPS Boeing 747-400 freighter flight crew became aware of a main deck cargo fire 22 minutes after take off from Dubai. An emergency was declared and an air turn back commenced but a rapid build up of smoke on the flight deck made it increasingly difficult to see on the flight deck and to control the aircraft. An unsuccessful attempt to land at Dubai was followed by complete loss of flight control authority due to fire damage and terrain impact followed. The fire was attributed to auto-ignition of undeclared Dangerous Goods originally loaded in Hong Kong.)
  • B738, vicinity Paris Orly France, 2018 (On 7 February 2018, a Boeing 737-800 experienced an airspeed mismatch during takeoff on a post maintenance positioning flight but having identified the faulty system by reference to the standby instrumentation, the intended flight was completed without further event. After the recorded defect was then signed off as “no fault found” after a failure to follow the applicable fault-finding procedure, the same happened on the next (revenue) flight but with an air turnback made. The Investigation found that the faulty sensor had been fitted at build three earlier with a contaminated component which had slowly caused sensor malfunction to develop.)
  • L410, Isle of Man, 2017 (On 23 February 2017, a Czech-operated Let-410 departed from Isle of Man into deteriorating weather conditions and when unable to land at its destination returned and landed with a crosswind component approximately twice the certified limit. The local Regulatory Agency instructed ATC to order the aircraft to immediately stop rather than attempt to taxi and the carrier’s permit to operate between the Isle of Man and the UK was subsequently withdrawn. The Investigation concluded that the context for the event was a long history of inadequate operational safety standards associated with its remote provision of flights for a Ticket Seller.)
  • DH8B, en-route, west northwest of Port Moresby Papua New Guinea, 2017 (On 4 August 2017, a de Havilland DHC8-200 was climbing through 20,000 feet after departing Port Moresby when a sudden loud bang occurred and the aircraft shuddered. Apart from a caution indicating an open main landing gear door, no other impediments to normal flight were detected. After a return to the point of departure, one of the main gear tyres was found to have exploded causing substantial damage to the associated engine structure and releasing debris. The Investigation concluded that tyre failure was attributable to FOD damage during an earlier landing on an inadequately maintained but approved compacted gravel runway.)

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