Speed ​​over the limit?

João Carlos Pó, Director-General of Mozambican Airlines (LAM), admitted in Quelimane, that the incident that occurred on Friday (26) with the aircraft that carried about 96 passengers, may have been due to speeding on the part of of the pilot when landing, and according to Pó, when this is so, the braking force is applied. However, the source says that only the ongoing investigation can bring results. These statements seem to be consistent with a deeper braking skid. On this subject it is known that by default the manufacturer recommends landing F30 flaps with some but exclusions such as landing on short runways, landing assisted by ILS (Instrument Landing System) or contaminated in which for these cases F40 is the recommended The F40 position (fully lowered flaps) has a lower approach speed than F30. However, many companies have mandated the use of F30 in all landings, leaving the F40 as an available resource for the indicated cases.

In the case of Quelimane, it is known that the track does not have much margin of error (short) and was contaminated. It would be interesting to know to what extent the imposition of use of F30 and an incorrect judgment of the crew regarding the optional use of F40 in that case, did not contribute to a faster approach affecting the ability to brake in the course of the track. On the other hand, the FDR (Fight Data Recorder) contains elements that will explain if the approach was stabilized in speed and attitude as well as what was the final position of the selected flaps and then compare the performance of the crew with what the company determines in its SOP ( Standard Operating Procedures).

But only the investigation will determine which flap position is used and particularly if the approach was stabilized. In addition, a stabilized approach is the flight procedure and technique that aims to ensure that the approach and the final descent for landing are carried out in accordance with the intended flight path and without the need for excessive maneuvers, such as sudden turns or sudden changes in the reason of descent already in the vicinity of the airstrip. In these cases, in the event of "destabilization", a go around should be performed.  Something like this: More wing area means greater lift and therefore the approach and landing can be carried out with less speed. 

Flaps 40 is the most supported position, so it allows for a slower landing and braking in the useful runway space.  The manufacturer recommends a position before F40, that is, Flaps30 as the operating standard, which means the need for more speed in approach and landing, since the aerodynamic lift of the wing is less. More speed means more braking effort. It is interesting to know what LAM recommends in its SOP, but in those circumstances of contaminated runway, the F40 position seems the most appropriate because it is one of the exceptions for which that last flap position exists.